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Design Question for an Underground Home

08/27/2011 10:48 PM

This is kind of a "back of the envelope calculation" type of question. I'm not trying to get homework solved, or avoid hiring a civil engineer (that requirement comes later), but rather to get some ideas as to the cost of what I'd like to do.

I pretty much have a full-blown earthmoving and construction company's equipment at my disposal, including a 50-ton reach-stacker, a concrete mixer with a 100 yard-per-day capacity, dump trucks, backhoes, bulldozers, several semi-tractor-trailer rigs, a really well equipped workshop (120 x 80) and a 15-man crew who are pretty creative and really hard-working.

What I want to do is build a few underground houses. The basic design is to use High-boy shipping containers as the "building blocks". Stacked 2-high on a properly footed concrete pad, 6 40' containers on each side with a 24' space between the two rows of containers. Front and back of the house will have a row of stacked containers running perpendicular to the two rows of containers. The end result is a 2-story house that's 72' by 56'... and I want to bury it. The location is about 20 miles north of Lexington, Kentucky.

Support for the roof would be the perimeter wall and 2 supporting walls at 24 foot intervals running front to back the length of the house. I'm aware that shipping containers aren't going to support the weight of the roof, but the perimeter wall will be reinforced concrete with reinforcement steel welded to the exterior of the container walls, and an integral outer form made from steel taken from the shipping containers, again with the rebar welded to make this an integral wall filled with concrete. Same technique with the inner support walls.

In order to accommodate the 24' span across the "great room" in the middle, I want to precast some double-T support panels and place them across the top of the supporting walls and then pour a monolithic pad on top of that to join it all together and finally cover it with about 3 feet of earth.

I've done some simple calculations and I figure that if I make the double-T panels 4 feet wide with supports on 2-foot centers (these are 72 feet long) that I can have 18 inch support beams underneath and I'll be using about a thousand pounds of steel in each panel.

Figuring the height of the two containers to be 20 feet, how thick do I have to make my perimeter wall? Given that it's a steel-encased retaining and support wall, I was thinking that this didn't have to follow the old rules of thumb which would say that I need a 1-foot thick wall around the perimeter. The two interior support walls would likewise be formed with steel on both sides, reinforcement welded to the steel sides. Should they be the same width as the perimeter walls?

With those double-T panels and an additional pad poured on top of that, I'm looking at about a 10-inch concrete pad on top with 4" x 18" support beams below that on 2-foot centers. Lots of rebar and mesh. A lot of weight. On top of that, sits about 3 feet of earth, although that could be modified to 2 feet. The roof has to support light tractors and cows wandering across from time to time... It would be wonderful if we could increase the great-room's size to 30 feet wide, but at some point it becomes cost prohibitive.

The issues for me are the costs of the concrete, steel and containers. We can make concrete for about $60 a yard and we can get the containers for about $2000 each. Steel looks like it's about a $thousand per ton at the moment. Labor is not considered (think Habitat for Humanity) because it's a community thing. The houses are huge because they are for families with 8-10 children. These are farm dwellings, exempt from the building code in Kentucky.

We want to use shipping containers because we can pre-install all the wiring and plumbing, insulation, drywall, etc., in a central workshop, along with all the rebar welded to the exterior. When they're ready, we haul them to the site and weld them together. By having the form for the exterior perimeter wall already welded into place, we can use much closer tolerances in terms of the excavation. We can pre-cast the support panels at the shop and let them cure under controlled conditions prior to installing them. The idea is to be able to have everything ready, and then throw a modern-day version of an Amish barn-raising.

The major goals of the project are to have housing that is very low-cost in terms of both construction and later in terms of heating and cooling; safe, secure, sustainable and which blends in with the rural environment. We're building for the generations to come. One of the alternative floor plans has 11 bedrooms, 8 full baths, 4 water closets and in the words of the guy who drew it "would be perfect for a family reunion in about 20 years.... I figure we'll have about 40 grandchildren by then..."

Any thoughts? Am I off in the size of the support beams? How much of an additional pad do I need to pour on top of them? How thick should the support walls be? What kind of foundation (heavy clay/shale soil) would I need underneath the support walls?

This is in the design phase at the moment, so I can plan to cast columns and support beams if needed, but that changes the requirements for the foundation and it goes from there. Nothing is "set in stone" at the moment except the need to keep costs down. Free labor and all the available equipment is really helping in that respect, but I must be able to make some reasonable estimates.

I'm looking for basic ideas and figures. If we go forward with this an engineer is going to have the joy of doing all the math and getting the pencil sharpened for exact answers... and then stamping his seal all over the plans. He can even have the Droit du seigneur for the house if he wants it.... Right now, I'm just looking for cost estimates and that relates directly to the amount of concrete and steel I have to put into this. I do have experience building underground homes, just never anything this big.

Thanks
Brian

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#1

Re: Design question for an underground home

08/28/2011 12:49 AM

Religious survival cult?

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#3
In reply to #1

Re: Design question for an underground home

08/28/2011 2:06 AM

We're setting up a large direct marketing farm operation and want to plan from the beginning to have the lowest operating costs possible. Looking at the direction of energy prices, the real inflation rate, the real unemployment rate and a host of other factors the decision was simple: go underground. It's all about controlling costs and eliminating weather worries. Farming can be risky: some years are good, some are so-so and some years are bad. The best way to control risk is to control costs.

I have an underground home in South Alabama, and even in 100+ degree heat, it's a comfortable 72-73 degrees with no air conditioning running (the summer kitchen where we do our canning is outside). While my neighbors have heating and cooling bills that routinely range from $400 to $600 per month, our electric bills average about $110 per month. The house has no exterior maintenance cost and when I switch over to high-intensity LED lighting I expect my electric bill to go even lower. My goal is a zero net-energy usage home, but it will take a large PV array and a micro-hydro unit to get there.

The net present value approach of of comparing large monthly cash flows (utility bills, maintenance bills, etc.) out of the family budget to the increased up-front cost of going underground tends to make a rather strong argument against building a conventional home. When one has a large family it makes even more sense. Underground homes also tend to have lower tax assessments. It's really all about cash flows and making farming pay.

While your "religious survival cult" comment is understandable in light of current US society's take on people with large families, it's way off the mark in this case.

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#35
In reply to #3

Re: Design question for an underground home

08/29/2011 11:40 AM

An underground may be cost effective for a family's home or even for storage area, however I would not recommend it to be used as a barn or to house animals. Ventilation and air quality issues would be a main concern. Ammonia, hydrogen sulfate gas, humidity, etc would require enornmous amounts of air exhcange for even a small number of head. And then there is the issue of waste removal and feeding.

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#49
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Re: Design question for an underground home

08/30/2011 12:02 PM

Not to denigrate the OP's question, but this just made me laugh.

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#50
In reply to #49

Re: Design question for an underground home

08/30/2011 12:19 PM

I like the Mormon angle too

there should be plenty of room for sister wives

probably adequate numbers of heathens to exploit for fun & profit in that part of the world

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#2

Re: Design question for an underground home

08/28/2011 1:17 AM

You wrote, "Any thoughts?"

Yes, hire a licensed architect!

You are wiling to build an expensive structure that could potentially fail and possibly catastrophically and take life. You want to take life critical advice from people you don't know on the internet?

However, you won't hire a professional. Does that make sense?

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#4
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Re: Design question for an underground home

08/28/2011 2:20 AM

The question is do I go with a monolithic dome, build with shipping containers, or go another route? I was looking for a bit of help in the area of load bearing properties of concrete and steel. I didn't ask for specifics, I asked for general guidance so I could come up with cost figures.

Your assumption that I won't hire a professional is incorrect. There comes a point in planning when one has to make some basic cost assumptions and project those costs into the economic analysis for the project. Without reasonable cost assumptions, it's very difficult to justify beginning the project... and hiring the engineering talent to do the detailed calculations and planning is a project expense.

I will be required to have a licensed engineer do planning and design work before the excavations take place... but I'm not at that point yet. I'm simply trying to make some decisions about which direction this project will take.

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#7
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Re: Design question for an underground home

08/28/2011 8:07 AM

I think you need to pull in the pros at the very beginning of the planning stage.

Think of it. When you start any engineering project you need to lay down the requirements.

That takes two forms; what to build, and how to build. You need to do that in that specific order.

You are wasting your time and making extra work by trying to determine how to build before you have nailed down what you are going to build.

What you build will determine exactly how you will build. The requirements are devolved in that order and having professionals at the very beginning is the shortcut to getting to the project completion in the most timely and least costly way.

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#5

Re: Design Question for an Underground Home

08/28/2011 7:27 AM

I'm a structural engineer and it would piss me off no end to be hired just to run the numbers for a concept in which I had had no input.

Save money in the long run, pick your team now, they will be close enough to the program to avoid the dead ends where you will inevitably wander if you continue like to navigate without expert guidance.

Hiring your team now can save spondulics in the long run.

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#6

Re: Design Question for an Underground Home

08/28/2011 8:01 AM

I think 'nobody special' has his head screwed on correctly! If I was planning on building something like this, I would also want a ball park figure first to see if it was viable before I started spending large amounts of money on an Architect who may turn round and say 'It won't work but you still have to pay me bucket loads of money to be told so!" I think he is following a sensible route. Nothing wrong with back of the envelope calculations such as these! Why go in blind. When I designed my Summer extension, I worked it all out including all the material costs and the time frame. When I got the Architect in to do the final drafts, he was on the same page as me, knew what was in my mind and together, made a great team. He changed a few things, I changed a few things, but we both had the same goal. The price I agreed with the builders was within my budget and we all came away happy! I now recommend this Architect to all my friends and I do most of the Builders Electrical Installations! Happy Days.

Unfortunatly, I can't help you on this because I don't know the answer, but good luck to you and I hope it all works out well.

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#8

Re: Design Question for an Underground Home

08/28/2011 12:03 PM

Well, I think the OP is on the right track, but his concept will most definitely need some modifications, structurally speaking of course. BTW, I love the concept of Earth Shelter homes and have always wanted to build one for my own home since my high schools days long ago in the early 70's......well, maybe some day IF I can convince my wife! LOL I also love the concept of marrying used steel shipping containers with concrete construction to obtain an Earth Shelter! INNOVATIVE THINKING! Now if only I had a Kentucky PE License as I'd would want to be on board this puppy from the get go.......it's not every day you get to design something quite unique as this house!!!

My first concern would be the earth fill load, soil saturation, any vegetation, insulation boards, waterproofing, and transitory live loads from farm tractors and cows on the roof structure. I don't think your precast double-T concrete beams, as described, will be sufficient to carry those Live and Dead loads. You may be able to do so with deeper prestressed or post-tensioned concrete double tees, even at a 30 foot clear span. I'm a little concerned about DIY precast beams as you don't have the inherent strength of a prestressed/post-tensioned manufactured concrete tee, nor do you have the proper QA, concrete curing facilities and other quality controls. IMO, the 10-inch thick concrete topping slab atop the tees is overkill and should be skinnied down to possibly a 3.5-inch to 4-inch thick (to accommodate rebar and obtain necessary concrete cover) lightweight concrete slab (w/Pearlite maybe?) with steel welded wire fabric mesh or rebar reinforcement. I'd provide rebar hoop ties projecting out of the tops of the double tees in order to tie-in the topping slab to the tees. And don't forget a premium asphalt-based waterproofing foundation coating and a superior waterstop at the construction joints.....I suggest using Synko-flex primer and synthetic water stop for such applications. Make sure your roof structure has some pitch to it in order to provide adequate drainage.

Shacking up the shipping containers will work, but will involve a lot of field welding to tie them alone together, even with shipping lugs, as we're talking about a tremendous amount of roof load as well as lateral earth loading from the exterior walls. Make sure you sandblast the exterior container walls to remove all rust and paint to obtain a good steel-to-concrete adhesion surface. Also, in addition to the wall rebar cages shop welded to the container exterior walls I'd suggest using Nelson shear studs of the container roofs and exterior wall surfaces.

I regard to the exterior concrete walls: if the walls are designed as a composite with the container steel walls and rebar 12-inch to 14-inch wall thickness may work with a 20 foot height, but the rebar sizes and amounts are going to be greater than what you'd find in normal house and commercial construction. The walls most likely be designed as a "propped cantilever" wall with fixity at the base and simple bearing at the top, or a fixed base and top type wall with rebar vertical and horizontal cages located at both wall faces (doubly reinforced wall). Again, proper waterproofing and water stops throughout are required as well as proper foundation drainage, including floor slab underdrain system.

The exterior wall footings will probably be greater (thicknesses and widths) then you envision due to the superimposed heavy roof backfill and concrete construction loads + any live loads, and the height of the wall backfill of 20-feet + the 3 feet of roof earth backfill. Most likely the exterior wall footings will need to be designed much like a cantilevered retaining wall footing with the lateral sliding forces resisted in-part by the first floor slab on grade. Make sure you have adequate footing drains with a positive un-submerged outlet. Do not build this home on flatlands, but rather build it on a hilltop or provide a partial backfill mound. Wall backfill can be well graded Run-of-Bank gravel if you have access to that type of material. In regard to the foundation subgrade and subbase materials: due to the clay and shale/clay soils you may have to undercut those in-situ materials quite a bit and provide a good thick foundation gravel, such as a "Crusher Run Gravel" (like NYSDOT Item #4), proof-rolled and compacted to no less than 98%-100% Modified Proctor Density. I'd get a KY licensed/registered Geotechnical Engineer on board first thing along with the Structural Engineer, as they need to coordinate their work together accordingly. You're going to have to have soil borings taken of the soil and have them lab tested so that the concrete foundation can be properly designed. I have great concerns about both short-term and long-term consolidation of the underlaying soil mass, especially in light of the heavy structural loads that would be imparted upon it.

That's it for now as this has gotten way too long already....

===Signed,

Captmoosie, PhD / NYS PE

Civil/Structural/Environmental Engineer

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#9
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Re: Design Question for an Underground Home

08/28/2011 1:55 PM

You wrote, "I also love the concept of marrying used steel shipping containers with concrete construction to obtain an Earth Shelter!"

We can't do that down here in Florida, so my plan would be to bury a surplus submarine. Ultimate hurricane shelter as long as guests do not try to fire a torpedo.

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#10
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Re: Design Question for an Underground Home

08/28/2011 2:14 PM

That would get a bit sticky!

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#12
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Re: Design Question for an Underground Home

08/28/2011 6:05 PM

Actually, earth-sheltered homes are possible Florida, you'd simply have to build on grade and cover it when completed... unless you're objection is based on the soil stability... but that is simply an engineering problem. My plans are to dig, build and cover because the terrain of central Kentucky lends itself to that procedure. You could go with earth-sheltered in Florida and I know this because others have done so:

http://www.deseretnews.com/article/700049169/For-some-home-is-where-the-earth-is.html?pg=2

http://sandhillburrow.blogspot.com/

The resistance to hurricanes, tornado, wildfire and earthquakes (depending on the foundation) are all significantly superior to conventional dwellings... and as one of the articles points out: "prices are on par with traditional homes, though mortgages often are paid off faster because of reduced heating and cooling bills."

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#13
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Re: Design Question for an Underground Home

08/28/2011 6:55 PM

Yes, but for the vast portion of Florida, even elevated berms will wick water up into them.

That, and we get some rain here. A few years ago we got nearly 30" of rain over a two day period.

That may a bit excessive for our location, but you do not want to be below any water line when that happens!

Our house was high and dry thanks to the builders' forethought to build atop a good berm.

The other enemy here is mold!

While I am a fan of earth berm homes, they would be a risky adventure here. However, they are popular way up north where winters are severe.

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#14
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Re: Design Question for an Underground Home

08/28/2011 9:00 PM

You forgot to include hand grenades, and.... Biological, Chemical and Thermonuclear weapons (NBC) to your list...

But the most important missing item: repelling a Zombie Attack! What a "pill box"!

Just kidding!

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#11
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Re: Design Question for an Underground Home

08/28/2011 5:04 PM

CaptMoosie, I had the feeling that I'd get a response like this from you. Thank you very much. A couple of points of clarification:

Two of the guys on my crew have a combined 15 years experience working for Gate ( http://www.gateprecast.com ) and they are automatically in charge of any precast work. We aren't thinking of trying to do prestressed/post-tensioned work, but the QA and quality control should not be a problem. Given the lower load-bearing capacity of a simple reinforced concrete T, my thought was to oversize it. When Engineering provides the final specs, my guys can build it. For cost analysis, would a 25% increase in beam size be adequate?

I have found that for waterproofing, a bituminous coating covered by either sprayed on urethane foam or urethane board insulation (sealed at joints with sprayed foam) forms an excellent water barrier and provides some of the needed insulation for the structure. A J-DRain system on top of that should mitigate mitigate any water infiltration issues. Yes, plenty of foundation and underslab drainage is going to be necessary and I already had the feeling that a significant gravel pad would have to be laid and compressed into the soil. Styrofoam insulation underneath the foundation and slab floor will also serve to further waterproof the structure. Costs of that have already been included into the calculations.

The building sites we're currently looking at are all on a ridge; the general plan is to cut a saddle across the top of the ridge, build and later cover the top, leaving a swale on either side with drainage away from the structure. This also gives us a means of ingress and egress on both the north and south side of the building as well as maximizing natural lighting. That's one of the reasons for the central gallery running down the center of the home- to maximize the ingress of natural lighting. I believe that if your wife toured a completed home of this basic design layout she'd be 90% of the way toward wanting to live in a home like this. Show her the utility bills and arguments would probably cease.

Anyway, with respect to the soil issues, I'm only hoping that we'll still be in soil 20 feet down. A lot of this area is into rock formations around 15 to 20 feet down, and in some cases one only needs to penetrate 4-5 feet to hit rock. The dominant formations in this area are Garrard Siltstone and Kope and Clays Ferry Formations, which offers both challenges and solutions to the soil stability issues. This is interspersed (depending on elevation) with the Lexington Limestone formations. Typical road cuts look like this:

http://4.bp.blogspot.com/-el_aAHFpJ_c/Td5B-50m2ZI/AAAAAAAAHbA/Z5rKQMQe6hY/s1600/20110515P+Maggie+Valley+to+Findlay+013.jpg

With respect to field welding, we have multiple Miller 300 Amp MIG/TIG generator units as well as several plasma cutters. With light-weight portable booths the field welding is not problem... but 90% of the welding will be done in the shop. One of the things we kicked around was imbedding I beams in the foundation with the tops exposed in the surface of the slab and welding the containers to that. Don't know if that's overkill, but it would certainly add to the strength of the foundation. An added benefit is it makes screeding the slab a lot easier. The downside is that more care would have to be taken when acid-staining the concrete floor during finishing.

Anyway, my take-away from your post is that the load-bearing walls need to be 12-14 inches thick with attendant foundational support underneath. The precast panels need to be sized larger (deeper support beams) but the overhead slab doesn't have to be as thick. Steel sizes increased by a factor of .5 to .6 and even then I'm coming in at a material cost to build these things at about $22-$24 a square foot. That's within the cost parameters.

That piece of information allows me to finish up the draft project proposal with a bit more comfort and present it for evaluation. The homes are simply one aspect of this project, but critical for the families involved. The costs associated with building the homes are critical for the investors, but we have to build homes anyway so the only question is what will it cost and what those costs will give us. Perhaps a good engineer can give us a more elegant solution to some of the construction issues... but in the end it doesn't matter. If we can build this kind of housing for $22-$24 a square foot, inclusive, then it's going forward and nobody is going to complain. Everything after that is just details.

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#32
In reply to #11

Re: Design Question for an Underground Home

08/29/2011 10:14 AM

For waterproffing you might consider Xypex, either as n admix or applied to the interior of the concrete (it can be sprayed on). It chemically bonds and penetrates the concrete pores. It has been test to a pressure head of 405' of water without leaking. it is non toxic and has no VOC's. It is used on underground storage tanks and structures and will hold up well to chemicals. And no, I don't work for them.

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#33
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Re: Design Question for an Underground Home

08/29/2011 10:56 AM

I gave you a GA for the Xypex suggestion.

I've specified it many times in the past for hydraulic concrete structures and all types of underground structures and it has yet to fail my expectations even once in 2 decades.

GREAT PRODUCT!!!!

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#44
In reply to #33

Re: Design Question for an Underground Home

08/29/2011 8:20 PM

Thanks Capt Moosie! But I take my hat off to you for your great GA. And I just use Xypex for the first time for a basement project.

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#15

Re: Design Question for an Underground Home

08/28/2011 9:37 PM

Looks like you're right on track and know what you're doing. I presume you're a General Contractor?

I think bumping up the T-beam stem width to -inches may be necessary, just to be able to fit the main bars in as well as the stirrup bars...for concrete cover and minimum acceptable spacing between the main bars. Also, for cost crunching purposes I'd probably bump up the initial overall beam depth to 22 or 24 inches. That's a heck of a lot of load they're going to carry at 30-foot span. I'd probably aim for no less than a 5,000 psi concrete compressive strength (f'c) at 28-days age. You're going to need that extra bit of strength.

In regard to the overall concrete picture requirements, especially for providing water tightness (for nearly the entire structure), I'd go with a very rich concrete mix, possibly using up to 650# of Portland Cement per CY, but also use up to 17% Fly Ash (Type F) by weight as a substitution for an equal weight of cement. Also, keep the Water-to-Cement Ratio (W/C) down around 0.40 and a maximum slump of 3 inches...air entrainment use in the mixture per ACI is a must, even in Kentucky.

You can juice up the mixture with a mid-range plasticizer for workability issues, but don't add additional water during the production run or later during it's placement. All of this will give you a very dense and high-early strength concrete that will be very resistant to passing water. It may absorb the water, but it will have a hard time passing through the concrete elements. The key to all of this will be not to strip the forms for 10 to 14 days after concrete placement (to prevent the surface from drying too soon and prevent accelerated shrinkage crack rates) and having proper concrete curing....wet curing would be the best, with flooding the hardened (after setup) concrete the most preferable way to provide wet curing.....this will minimize shrinkage and micro cracks. Additionally, using poly fibers in the mixture will help with the micro-cracking problems. Also, by providing nearly double the required minimum Shrinkage & Temp steel ratio (per ACI 318) will help a lot towards minimizing shrinkage cracking. I've used this approach many times very successfully in water and wastewater treatment plants and other hydraulic structures.

Good luck with your project!

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#16

Re: Design Question for an Underground Home

08/28/2011 10:50 PM

Apple's fortune was founded by guys playing "what if" on their spreadsheets. It is interesting to try to incorporate something big, cheap and strong like a container into a building. Done artistically, it can create a nice space.

At this point, what is needed is a brainstorming session on different ways to arrange things to minimize the material needed. A CAD program with FEA could be a handy assistant, or anyone who is adept at running one to get comparisons between different beams, etc.

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#17

Re: Design Question for an Underground Home

08/28/2011 11:06 PM

Seeing as it is a community thing, try getting in touch with the Extreme Home Makeover guys. They might take an interest and give more help than you ever deamed of.

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#18

Re: Design Question for an Underground Home

08/28/2011 11:47 PM

Fascinating. You guys are out on the bleeding edge of human survival. If sometime in the later part of this century our planet experiences a methane burp and we are fighting wars over who gets to colonize Antartica your names will be elevated to the status of devine prophets. .......Ed Weldon

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#37
In reply to #18

Re: Design Question for an Underground Home

08/29/2011 12:30 PM

I see I got under at least one person's skin with my snarky OT comment. Just the imp in me.

In reality I have a lot of interest in and respect for Brian's objectives and his real world approach to the underground home. I'm an engineer myself and know from my own career experience how constrained the thinking of an engineer can be. I've also seen enormous success stories grow out of problems approached from a "what can we build" direction.

Large constructions that are full of new challenges and innovative ideas can present a Gordian knot of engineering problems that require solution. The winnowing out of these problems in the abstract can require enormously costly engineering effort to reach the point where the important problems are illuminated. NASA's manned space program is a good example.

There is much appeal in today's world of computer analysis and design for the idea of designing everything first. But I think any experienced engineer will tell you that his usefulness in early concept stages of a project derives primarily from his own past experience well tempered with the numerical refinement that comes with his profession. To that end I believe the professional engineer participating in Brian's project at this point should view this as an advisory "cost of sales" effort rather than "billable hours". Engineers have a different view point from the builders and this is important at the project feasibility stage. And the best engineers will have enough confidence in their own capabilities to allow themselves to bring the necessary creativity to this party.

Captmoosie has raised his hand to the extent he is able to participate; the burden of geography and state licensing among others being an obvious restriction. Perhaps there is some engineer closer to you who is ready to invest his time in working with you on what I believe to be a major future building trend for upscale detached home building.

Regardless of your beliefs on the subject of climate change recent experiences with weather extremes are telling us volumes about the risks and costs of present day home construction methods. The demand for new approaches can only grow in the near term. I feel this is a ground floor opportunity for smart building contractors and civil engineers.

Ed Weldon

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#19

Re: Design Question for an Underground Home

08/29/2011 1:16 AM

I wonder if you have considered a cost effective concrete, floor, wall & roof solution

like "CorCon" (corrugated concrete) a fast, simple, re-usable formwork system -

http://www.corcon.com/

That would help you keep cost down & build an earth covered structure.

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#20
In reply to #19

Re: Design Question for an Underground Home

08/29/2011 4:04 AM

Well, CorCon sounds good on paper, but after wading through the website and looking at their data, if I'm right it looks like their strongest product only has about a quarter of the strength I need. It's interesting and I really wonder what the arching would do to the kind of panels I'm planning on casting... but those kinds of ideas are where things really go off into the weeds... I want to build buildings, not develop new building technology. Cost savings are great, but design intention/parameters and field use have to match. My earth load alone will be about 3000 pounds per square meter (13.35 kN/m2) when it rains, and then there's the weight of the concrete and steel in the roof to consider and we still haven't adjusted for live loading or added a safety factor. We wouldn't want cows falling through the roof, now would we? Instant family legend status is to be avoided at all costs.

It would be nice if CorCon linked to even one website that actually gave a reasonable description of their products, services, prices and options available, but such is not to be. Does the company offer support to special engineering considerations? Who knows? If they were willing to take my basic load support requirements, compute the solution using their techniques and manufacture the appropriate forms and plates for me the only question left would be the cost... but I'd want to see some evidence that their solution would actually work... and then somebody would have to work their technical parameters into the project... and whoever got that headache would send me a hefty bill for the indignity of being forced to learn something new.

This is starting to look like a 6 or 7 beer discussion... winding up more confused at the end than when it started... headache to follow.

It appears that CorCon's design parameters aren't compatible with my project load support requirements... and the bottom line is that I'd rather have an over-engineered solution that's somewhat wasteful of material... than live under a very real (concrete and steel) sword of Damocles... no matter how elegant. Anyway, I like the idea of precasting my own supports in a controlled environment because if nothing else, it offers a lot of ease in terms of materials handling and quality control.

Love the CorCon idea, but don't see the application for this project. However, I do really appreciate you pointing this out to me- it does have application for some other projects I have in mind. Thank you for taking the time to do so.

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#21

Re: Design Question for an Underground Home

08/29/2011 4:15 AM

I suggest forget the containers,build reinforced concrete walls,they wont rust or sweat,you're talking of backing the containers with concrete anyway so save the cash and be shore it will last 200years,once it is built you can batten and board the rooms fitting electric & pipes behind.

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#23
In reply to #21

Re: Design Question for an Underground Home

08/29/2011 5:21 AM

My thoughts exactly. except, maybe forget the concrete walls, and reduce the mass (as Capt Moosie suggests) of the roof. Possibly bridge the containers with steel, insulate with foam, waterproof, etc., then green it up. I believe fully loaded containers can be stacked at full load (50,000 lbs) to at least ten, possibly 12, high, with a safety factor of 1.5. Welded, they would have exceptional rigidity and load capacity far beyond the stacked rating. That is without opening the doors, of course.

The interior space could be quite dismal, I believe., but we all need lots of closets, pantries, utility rooms and bathrooms, don't we. Windows, doors, etc., will require some aggressive engineering creativity. It is very interesting, and I wish you good luck. Good builders explore technology in the field in ways that non-builders don't, and sometimes those ideas are novel and progressive, moving the bar along.

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#22

Re: Design Question for an Underground Home

08/29/2011 5:19 AM

Good thread, once we got past the if you have to ask the question, you're not qualified to understand the answer phase of the program...

Here's a bit of unrelated shipping container porn

http://thechive.com/2011/07/26/unbelievable-home-built-out-of-two-shipping-containers-39-photos/

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#24

Re: Design Question for an Underground Home

08/29/2011 5:50 AM

I believe you would be better off using precast concrete culvert sections.

Have some fun today,

PAPADOC

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#25

Re: Design Question for an Underground Home

08/29/2011 6:01 AM

I live in a Geodesic dome and at one time had thoughts of trying to go underground. I believe they would be well suited for this application.

In a 3 frequency dome there are only 3 different lengths of members to deal with. With a little color coding, even the kids can help put one together. You will not need a crane to assemble the structure.

Since the geodesic dome design exerts all the stress to the connecting hubs, if your structural engineer needs more strength then the only variables are the width of the struts and size of the connecting plates. That alone would make your spreadsheet guestimating scalable and a little easier.

There is less material needed to enclose the space than is needed to enclose a similar sf of a box.

The waterproofing will not contain right angle bends (except at the connection to the footing).

I am not sure what size your shipping containers are or how much work it would take to clean them up or strengthen them, but it would seem the cost per sf of floor space would be less with the dome option.

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#26

Re: Design Question for an Underground Home

08/29/2011 7:31 AM

What you are planning on and technique will be non livable, Underground homes if built correctly are wonderful homes with many advantages. I know I built one to view go to www.domehome.ca lots of photos and discussion on what can go wrong. No need to have issues as I did due to contractor screwing up in many areas. My contractor was Terra Dome they are in Missouri and they have the forming system but you have to watch them for some reason they are prone to laxity to detail and outright foolishness. Underground homes never have any insulation on the inside unless you are best friends with mold and mildew. Closed cell insulation on the outside of the cell is 100% mandatory both in insulation and in moisture control. Good luck.

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#27
In reply to #26

Re: Design Question for an Underground Home

08/29/2011 8:37 AM

With my underground house, I learned the hard way not to skimp on exterior insulation, so this project calls for 4 inches of sprayed on polyurethane foam on the walls and roof and insulation boards under the foundation and slab. I have sprayed on polyurethane foam on the inside of my home with no problems with mold, but outside is better. As long as the thermal transmission is controlled and warm moist air on the inside isn't coming in contact with a cool wall, the resultant condensation of water doesn't occur and everything is fine. However, you're correct in saying that insulation needs to go on the outside.

It's funny, but there is one structure that we won't insulate at all and we're hoping for some good mold. The farm will have a seasonal dairy and all the milk (what we don't drink) will go into artisan cheese production. We need a "cave" to age the cheese in, so we want our storage to be the ground temperature. Very little air circulation other than a small thermosyphoning vent, so the temperature will equalize and there won't be any sweating walls.

The main reason for using the shipping containers is cost, because it saves the cost of framing the interior. At $2000 for a 40 foot container, I'm essentially framing each floor for $6.25 a square foot, along with the ease of welding whatever I want wherever I want it. Their structural rigidity is great and using the steel removed from container sides (to make larger rooms) I can make permanent forms for the exterior walls with the reinforcing steel welded to both sides. Four inches of sprayed on foam on the outside... and the walls and ceiling become a giant heat-sink that maintains the temperature on the inside.

In addition, each container can be worked on in a shop environment (like modular homes) to centralize materials and tools for increased efficiency. All the plumbing, electrical and most interior finish work (drywall, for example) can be in place before the units are assembled on site. This is a more efficient use of labor and resources. Completed units can be stored outside awaiting transportation to the site. When all are completed and the foundation/slab is ready, the whole thing can be assembled in a day and we can be ready to start pouring the exterior walls the next day. Again, more efficient use of labor and resources = less cost. I'm not paying for the labor, but there is definitely an opportunity cost for every man-hour on this project.

I'm the contractor for this project, but worrying about "screwing up" isn't the real problem. That implies that I knew I was supposed to do something and didn't do it, or made a mistake in something I did do. The real problem is not knowing the right questions to ask or issues to consider, because if one doesn't know the questions to ask then there eventually comes that moment when you turn around and meet Mr. Murphy. His visits can be expensive.

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#29
In reply to #27

Re: Design Question for an Underground Home

08/29/2011 9:21 AM

I have heard of worse projects and you are on the right track on many issues. May I suggest a back door option.

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#30
In reply to #27

Re: Design Question for an Underground Home

08/29/2011 9:25 AM

You might get away with installing drywall, but I would wait until the installation is completed to mud the walls unless you want to be fixing cracks at all the seams.

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#31
In reply to #27

Re: Design Question for an Underground Home

08/29/2011 9:36 AM

"I'm the contractor for this project, but worrying about "screwing up" isn't the real problem. That implies that I knew I was supposed to do something and didn't do it, or made a mistake in something I did do. The real problem is not knowing the right questions to ask or issues to consider, because if one doesn't know the questions to ask then there eventually comes that moment when you turn around and meet Mr. Murphy. His visits can be expensive."

Kudos for taking responsibility for the project design. If you look at the comments, it appears to have a high difficulty factor, with a lot of potential for "screwing up"

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#43
In reply to #27

Re: Design Question for an Underground Home

08/29/2011 7:29 PM

Have you thought of using reefer containers? They are already insulated, and just need a solid floor to go over the pre-existing 'ridged' floor. It would certainly save on fit out costs.

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#28

Re: Design Question for an Underground Home

08/29/2011 9:12 AM

Call Gadhafi he might give the specs.

Vince

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#34

Re: Design Question for an Underground Home

08/29/2011 11:37 AM

Brian - If you're set on this construction technique I will not sway you, however, if you want something that is simple, stronger (w/o interior support), more energy efficient and quicker, go to my friend, David South's site, http://www.monolithic.com/ , to investigate a concept he has used underground before. Just a thought.

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#36

Re: Design Question for an Underground Home

08/29/2011 12:06 PM

My suggestion is to forego the shipping containers and take a look at the pre-cast construction techniques commonly used for parking structures. Tip-up concrete walls and pre-cast roof spans should easily provide a 56'x72' open space that will withstand the backfill and live loads, and would not use any more concrete than the plans you described. You would then be free to frame in the rooms any way you want without being constrained by steel walls 7-8 ft apart. I would suggest avoiding the live loads by placing your vegetable garden over the house.

I must be missing something because I cannot see how you get the dimensions you provided. Exterior dimensions of hi-cube containers are 40'x8'x9.5'. Standard containers are 8.5' high. (2) rows of 8 ft wide containers with 24 ft in between= 40 ft. 6-40 ft containers in each row, doublestacked so each row is 2 containers high and 3 containers long is 120 ft long. Adding the containers across the front and back gives a clear space between the containers of 24'x120'

Trying it a different way, a 40 ft container across the front and back, and the side rows beyond them give 56 ft wide overall (40'+ (2x8')). Overal length with (2) 40 ft containers down each side would give an 80 ft overall length (depth). This arrangement gives a 40'x66' clear space between the cantainers. Adding another container to each side row increases the space to 40'x120'.

A diagram would be very helpful.

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#38

Re: Design Question for an Underground Home

08/29/2011 12:48 PM

Brian (and Captmoosie) -- I have one other thought on this project and it relates to what seems to be the major stumbling block you guys are working on. (I'm a layperson here; a mechanical engineer cannot add much useful technical content to this discussion)

What exactly are you trying to accomplish with the "roof" of this structure? I'd suggest a written list of the objectives of the roof structure and a critical evaluation of the importance of each. Maybe assign a dollar value. Yes, I understand the emotional value of preserving some 4000 square feet of farmland and the sales publicity that can come from finding the right engineering design for the job. But realize a whole lot of painful development work and failures may precede that lofty goal.

In other words, is it truly critical that you climb to the peak of the mountain when you are still working on the hike to the basecamp? .......... Ed Weldon

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#45
In reply to #38

Ok... the defense of the thesis

08/30/2011 1:49 AM

Thank You, Ed.

I feel like I'm making the oral defense of my dissertation without having provided the committee with the text... but I figure I should be able to at least defend the project design goals at this point so I'll take a stab at it.

We start with the desire to build underground, which is the result of many factors, but essentially it comes down to this: if I have to build a house and I want said house to provide a safe haven for multiple generations under conditions of which I can only speculate, what's best for me and my future generations? Forget about what's best for the contractor's profit or what everybody else does, what's best for me and my family in the long run?

The cost advantages over the life of the structure and the peace of mind associated with living in a safe and secure underground home make a very persuasive argument in this case, especially if the design is aesthetically pleasing. There are many costs to be saved and the NPV of the cash-flows against the increased up-front costs got weighed.

The ability to have a reliable and livable shelter in disaster situations (electrical service failure due to storms, etc., especially in winter) and protection from violent weather events such as a tornado was another factor. We don't know what the future will bring, but nobody can deny that the infrastructure of the US is crumbling and the needed reinvestment isn't being made. Energy costs are going up and barring a new technology (such as what Dan Nocera at MIT has developed) actually being put into widespread use, all rational analysis says that energy costs will continue to go up.

The end result of the comparative analysis of above-ground housing with below-ground housing resulted in a decision to build underground structures. That required a workable design... and cost considerations were definitely part of this. The only two reasonable and cost-effective designs are "conventional" and the monolithic dome. The shipping container idea is actually just conventional design using modular construction based on steel box "building blocks" that happen to be post-consumer recycling bargains.

However, the structure still has to support the load of the dirt on top of the roof; and this is where the aesthetic considerations, the engineering requirements and the cost constraints must intersect. Each is a variable curve and I am trying to maximize aesthetics while minimizing costs. At some point the engineering requirements will form a ceiling, but that point depends on the design. The purpose of the roof is to hold up the dirt that goes on top of the house. That dirt is the protective and living "cushion" that protects the house from whatever comes along.

This all comes down to the load bearing span requirements and the available support from below. Since the loads are known (weight of the roof and 2-3 feet of soil for the dead load; rainwater saturation, livestock and mowing machines for the live load), the question becomes "what is the best-cost solution that offers the needed support with a reasonable safety margin?"

I'm focused on a multi-span slab supported by precast T beams because it appears to be a well-proven engineering solution that will work for my situation if properly designed and built. With that design consideration, the only question left is what the specifications will be for thickness, depth and reinforcement steel within the T-beams; the reinforcement requirements for the pad on top of the beams, the requirements for the walls that will support this structure and finally the foundation requirements that meet the needs of the structure on top of it. The answer is to get a decent engineer to do the calculations based on a number of specific factors such as soil conditions and such.

With the design specifications in hand it's a question of whether I can manufacture my own pre-cast beam components with sufficient strength (now the quality control becomes important) and at a reasonable cost. Can I put the whole thing together at a reasonable cost compared to other solutions?

I submit that I believe my solution is a better fit at a lower cost with a higher aesthetic appeal than what I could do with a monolithic dome.

I also had to consider the labor requirements even though I don't have to pay for it out of pocket: Each container (40 ft x 8 x 9.5 ft) has about 320 square feet of floor space. I can have each of them ready to mount in place with 30 man-hours of labor because the dependencies in the critical path aren't that onerous. A 5-man crew can knock out a container per day and with experience we could probably cut that to a 4-man crew. 20 containers per home is 4 weeks for one crew. Another crew of 5 prepares the site, installs utility lines, pours the foundation and slab, etc., while the modular units are being prepared. The third 5-man crew is alternately working on the precast concrete and providing support (hauling aggregate, forming material, etc., and the timeline allows for a full 28 day cure time in the forms for the precast if I build at least 14 forms.

That means about 5 weeks of prep time necessary prior to stacking the modules, pouring the walls and laying the roof in place, so we'll call it an 8 week schedule from groundbreaking to liveable home. If I can develop just 10 of the older teenagers attached to this project into reliable workers, we can seriously overlap construction of the houses.

Back to dollar values. I'm looking at building 7000 sq. ft homes for less than $25 per square foot in material cost and an associated labor input of about 5000 man hours. If I placed a labor cost of $25 per hour on this project I'm still building for only $43 per square foot. This is about half of the local building cost for "average tract homes" ($88/sq. ft.) in the Lexington area. If this is considered an "above average tract home" then I'm coming in at 42% of the local building cost ($103/sq. ft.). God forbid you call this 8-bedroom 8-bathroom 7000 square foot monster a "luxury" home because the average construction cost for McMansion's in the Lexington Area is $161 per square foot... I prefer to think of what we're going to build as "castle construction" along the lines that every man's home is his castle.

Call them what you will. The end result is the production of homes with a conservative market valuation (if valued at the construction cost for an "average tract home") at somewhere around $581,000... for an outlay cost of about $175,000 plus community support.

But... somewhere in here there is a need to go back to the question of why we're doing all this in the first place. The answer is that the people involved in this project didn't just do a comparative analysis of home design... it was more of a comparative analysis of lifestyles combined with some basic trend analysis and expectations for the future. The end result was a decision to create a project for a multi-family farm somewhat resembling a Hutterite community (without the communist or pacifist elements) that focuses on direct marketing the farm products to a local population center.

Multiple families means we can have a meaningful division of labor for greater efficiency and a deeper pool of labor to draw on in times of crisis. It also permits a level of specialization that allows the farm to be far more self-sufficient than any single family farm could manage. Think of it as a throwback to the small farming communities of a hundred years ago. Think "mutual interdependence" within the community instead of "rugged independence" that is the hallowed "American Way" (TM). By keeping costs at rock bottom during the critical start-up years we are in a much better position compet with established competitors on a price basis and also be more profitable in later years after we've gained a sustainable market share.

The farm plan will provably generate an annual pre-tax income of $125k after 3 years for each of the families in the project with 2% to 3% annual growth above real inflation. Building multiple large homes and associated work spaces, I can not only get volume discounts on a lot of materials, I can also spread the cost of forms and special equipment over the entire project. Did I mention the dairy barn and cheese factory, or the buildings needed to house the sawmill and lumber drying kilns, carpentry/cabinetry shop and the maintenance/machine/welding shop? No. Neither did I mention the composting operation, commercial abattoir or the restaurant that are part of the project plan. Those are separate elements within the project that aren't really related to the underground homes.

It would be safe to say that virtually every element in this project design has been thought through with respect to creating a synergistic community system and the homes are simply one aspect of the entire plan. However, the thrust of this thread was that I was trying to focus on a single engineering problem and get some ideas and input so I could figure costs.

Concrete and steel are well known substances. With properly engineered specifications this project can be accomplished with semi-skilled labor. That places a greater burden on me in the beginning, but I have some really good people, all of whom have construction experience in various areas. They also all have large families, so there is a large pool of young labor to draw on in time of need... and the kids will all get the opportunity to learn valuable skills.

We'll be able to produce our own kitchen cabinets, counters, molding and finishing material. In fact, by cutting, sawing and drying a small percentage of the standing timber on the farm and finishing that lumber into installed trimwork, each home can have a custom hardwood trim package (wainscoting, crown molding, door and floorboard buildups, etc.) that would cost $75k or more if one had to hire a contractor to install it. Do you think the teenage boys who learn how to do this kind of work will be able to get custom trimwork jobs with that kind of portfolio? Will Mama will be happy living in a huge, gorgeous home that gets paid off in only a few years? Well? Ya think?

What could go wrong? Lots of things. What I don't want to go wrong with the homes is water infiltration, structural failure of the roof or foundation, or any other problems that are generally preventable by following the recommendations of a proper engineering study. I also don't want this project to spend more money than it really needs to because we don't have preferential treatment at the FED discount window.

On a more practical note, someone suggested I consider having a "back door." As far as back doors, if the house won't open to both north and south, then the back of the house (hillside) will have at least one escape hatch, a ladder up to the surface level in a 36 inch culvert pipe. For security, the pipe terminates in a modified septic tank sized concrete box with a slab covering. The slab can be lifted by a hand-pumped hydraulic ram operating a scissor lift. Any child large enough to climb the ladder could operate the lift. If social conditions warranted it, the slab could be camouflaged or otherwise hidden.

Someone suggested that I tunnel into the hillsides. I suppose that if a decently thick enough layer of soft shale was found below a sufficiently thick enough layer of siltstone, we could tunnel through the ridges to our hearts desire in a fair amount of safety. That is, until the Kentucky Department of Mines and Minerals got wind of it. Somewhere between 50 and 100 feet into a hillside a "hole in the ground" suddenly becomes a mine. That is a Pandora's box of regulation and headaches we'll leave to no-name government agencies and Halliburton.

A friend of mine who is a tunneling engineer suggested that if a convenient strata suggested itself, I could communicate the various homes together with a 4-foot spherical tunnel (3-section culvert pipe for shoring) and use purpose built recumbent bicycles to navigate such passages. This was not the first of such suggestions and I concluded that hidden somewhere deep down in all engineers there lives a little boy... enamored of secret passages and hidden rooms known only to their select circle of friends.

Unfortunately, as a project manager I'm forced to live in the real world. Bury a culvert pipe up to a higher or lower elevation in order to gain a thermo-siphon effect on the airflow and achieve air circulation without the use of fans? Sounds good, but what's the cost/benefit ratio compared to brand X tech? Build secret tunnels because it's cool? Not even if someone handed me a winning lotto ticket.

As an individual, I might have different answers. As the project manager it's all about project design, project goals and cost/benefit analysis. If you aren't planning on climbing the mountain, why hike to the base camp?

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#47
In reply to #45

Re: Ok... the defense of the thesis

08/30/2011 5:17 AM

that hidden somewhere deep down in all engineers there lives a little boy... enamored of secret passages and hidden rooms known only to their select circle of friends.

...or girl. My first reaction to that suggestion was "YES!!!", but the realism needs to win out. Although....if the social breakdown we worry about becomes more likely, the practical benefits increase....

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#51
In reply to #47

Re: Ok... the defense of the thesis

08/30/2011 11:13 PM

Hi Rose. In hindsight, I should have made that comment gender-neutral. Mea Culpa.

In partial atonement I'll share some other considerations related to this (admittedly somewhat off-topic) issue of fortress architecture and tunnels. This is basically an abstract of the SWOT and PESTLE analysis from our project plan... with commentary.

______

Fortress Architecture could be of benefit if social breakdown were to occur... but unfortunately in and of itself such designs create significant risks while waiting for "the end of the world as we know it." This danger is the result of receiving the attention of Law Enforcement based solely on the "Fortress Architecture" and the resulting demonization by the local media that such attention would probably generate. Sounds crazy, doesn't it?

You can see a minor example of what I'm talking about in this thread: the first response to my OP got was "religious survival cult?" In other words, anyone wanting to build underground must be crazy, anti-social, lunatic fringe material. Today I got an anonymous poster making a significantly more sophisticated attack along the same lines.

Anonymous thinks the project is laughable either because I want to build underground or because I want to use shipping containers as building blocks for the construction, or perhaps both. An attempt is then made to marginalize the issue and ridicule me by linking it to radical Mormon polygamists. This was made easier because I linked to a story on underground homes in Florida published by the Deseret News. Yes, from a media management point of view I blew it: Never give the opposition any ammunition if it can be avoided.

That's just an example of what happens when you do something sufficiently removed from the mainstream point of view. This is the reality of the term "politically correct" because everyone intrinsically understands the very real penalties associated with being publicly branded a bigot, racist, fundamentalist, homophobe, or even... a survivalist.

What does that have to do with building an underground house, or with fortress architecture? It's all about perceptions and fear driving the Law Enforcement and Media business model. Allow me to explain:

The real problem is that at some level law enforcement officers are offended/irritated when someone builds a home that they can't easily break into with a SWAT team. It's a fear response. I ran into this attitude years ago when I had a side-business installing window security bars and Multi-lock style door systems. These doors cannot be pried open, kicked in or opened with a door jamb spreader because the mechanism sends bolts into the frame on all four sides of the door. They are equipped with locks that cannot be opened with "bump keys" or be easily picked.

Police patrols would often stop by to "check me out" when I was doing installations and after they observed what I was doing... I had several officers say I should turn over my client list and the addresses of all the installations to the police. Why? Because I was doing expensive security installations that prevented Law Enforcement (or anyone else) from gaining fast entry. Nothing short of a vehicle-mounted battering ram would open up one of those windows or doors in less than 10-15 minutes. If an installation address was in the "wrong" area, it would be assumed that it was a crack-house because "normal" residents in those areas couldn't afford this kind of security.

"What about the people in those neighborhoods (or adult children purchasing for their aged parents) who buy this because they're fearful of home invasion?" (that was the #1 cited reason for purchase). "Well, that's not normal- people who can afford top-tier security normally move to a better neighborhood..." was the response. I found their form of illogic immune to rational argument... and no, I didn't keep address records because the IRS didn't require it... and they didn't get jack from me.

Law Enforcement thinking typically works like this: "If someone is doing something out of the ordinary there is probably a sinister motive behind it because normal people obey societal norms and behave like everyone else." In my present case, Law Enforcement asks the question: "Are people using underground spaces to grow marijuana or set up meth labs?" See for yourself:

Tennessee: you must see this one- it's amazing, Las Vegas, North Carolina, Washington, Kentucky here and here and I could go on and on...

Law Enforcement research says that the trend in drug production is to go underground in order to avoid detection. Therefore, anyone building underground is immediately suspect and should be investigated when time and resources permit. If an initial investigation shows any "suspicious" associations or records in the system, a site visit is in order. If further investigation reveals the presence of fortress architecture, secret escape tunnels or other such goodies... that alone can be justification for a raid. Their attitude is that "Law-abiding people don't build this kind of stuff" and they can't imagine there are any good reasons to build underground homes or that someone might get peace of mind from a super-secure home.

If the fears and suspicions of Law Enforcement ground troops weren't enough, at the organizational level the ability to seize property afforded by the civil forfeiture laws have combined with worsening budget shortfalls to generate a situation in which the Law Enforcement Organizations have a palpable conflict of interest... and thus the likelihood of "evidence" being planted or manufactured goes up significantly. Unfortunately, this isn't hyperbole.

Any action by Law Enforcement is usually accepted as gospel by the news media and reported as such. Demonization follows and the trial in the court of public opinion is held with the media presiding.

This was an issue that came up first in the SWOT analysis and later in the PESTLE analysis contained in the project plan. Currently low in terms of probability, such a situation would be very high in terms of damage. Trend analysis says that the probability of such a situation will only go up over time. Low in probability but very high in damage is the rational behind purchasing fire and flood insurance...

Added to this is the problem that nobody will believe the construction cost figures on the left side of the equation and nobody will believe the farm income figures on the right side of the equation. The conclusion is that we must be dealing in drugs or doing something illegal. Once that conclusion is reached, no amount of education or proof will overcome the prejudice. The mindset is that if everyone else is building for about $100 per square foot, it isn't possible for you to build for $25 per square foot. If all the other local farmers require 3.5 acres to raise a cow, it isn't possible for you to raise a cow on less than one acre. Therefore, there must be a hidden (and illegal) source of income that pays for all of this stuff.

Unfortunately, there is no easy defense against this because what we're talking about is a Law Enforcement mentality... which is very much "us vs. them." Any "fear-based" justification for Fortress Architecture type construction only makes matters worse: Cite fears of monetary collapse and civil unrest and you are immediately classified as some kind of wacko-survivalist, with a home probably stuffed to the gills with weapons and ammunition. Kind and peaceful folks with strong religious beliefs who want a really secure home? You must be a Waco-style child-abusing cult. Combine the two? That's bad... really, really bad. Voice any concerns that the country is becoming a police state and that's strike three- you're out. May as well get ready because the raids are now in the planning phase.

I wish I was making this up, but the abuse of civil forfeiture by Law Enforcement is well documented, as is the growing trend of SWAT-style no-knock raids based on flimsy evidence produced by people motivated to invent such evidence in order to gain favor with Law Enforcement regarding their own criminal activities and pending cases.

Our conclusion was that the only reasonable defense was to first ensure that if asked, public communications must focus on the environmental aspects of sustainability. In other words we must "preach the gospel" of lower energy usage in a time of rising energy costs, safety from natural and man-made disasters and the (relatively) low cost of construction. Second, we must either eliminate or conceal any visible signs of "Fortress Architecture" and make the homes appear to be as non-threatening as possible. Third, we can eliminate a lot of local speculation and comment by building everything with our own people. Finally, we cluster the homes as a gated community to control access and give the appearance that we're far wealthier than we really are.

The most surprising thing that came out of this analysis (within the project group) was the resistance to the conclusions, all of which were completely data-driven. The issue was emotional and difficult to articulate, but the bottom line was that even when faced with the evidence... nobody wanted to admit that the mere act of building a safe and secure underground home might be the first step in a probable train of events leading to police investigation... and possibly culminating in an armed raid and search of the premises with the attendant media circus and public character assassination.

Illogical as it sounds, in the end we recognized that there was an unlikely but very real danger and we needed to ameliorate it in whatever way we could. To forgo building an underground home because of fears of probable governmental scrutiny and possible Law Enforcement action was to admit that we truly do live in a fascist police state... which nobody wanted to do.

Sometimes I envy you engineers.... you only have to deal with the physical aspects of a project. Project managers are required to deal with the physical and the business, social, legal and political aspects as well.

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#85
In reply to #51

Re: Ok... the defense of the thesis

09/20/2011 5:24 PM

As you suggest, if you build a replica of Hitler's Berlin bunker, the fascist police may regard you as a rival. However, aside from the political reasons, let me suggest a counter concept, if only for cost comparisons. Dig a hole or holes on your ridge, situated do that they can be drained by gravity. Use a minimum of retaining structure to support the walls of the hole, no insulation or waterproofing. Forego the cows on the roof. Put into the hole a simple structure with a roof, something like a pole barn or prefabricated steel utility building. The roof can be above grade, extended to cover the edges of the hole, but if water runs down the walls, let it drain into the gravel floor and out the pipe which runs downhill. Have at least a few transparent or translucent panels to let in sunlight. You now have a microclimate something like the coast of California, cool, moist, not likely to freeze or get too hot. You can grow ivy on the walls, plant trees and flowers and vegetables, all good for the soul. Then, on the well drained gravel floor, build a "California house"; a tent, a simple almost uninsulated wooden house, adobe, whatever. The roof of the house need support only itself, no snow or wind loads. Even in winter, one can look out a window or walk out the door and enjoy sunlight and greenery. The difference in temperature between the air in the hole and the desired indoor air is small, so heating or cooling costs are small. You may need shades on the skylights in summer, but passive solar heating is possible in winter if the transparent panels are properly oriented. Have several entrances/exits, in case of fire. If the paranoid police can peer through your roof and assure themselves the flowers are not hemp, that's one more thing not to worry about. True, you may not survive World War 3, but I'll bet the overall cost would be a lot less than the bombproof bunker, and it won't go dark when the power fails. By the way, I was recently in a port, St. Petersburg, Russia, if memory serves, which had several buildings, including a large-span passenger receiving and customs hall, which were built by stacking steel shipping containers about three high. Toilets, etc. were in the containers, but mainly they were load supporting walls for the large hall.

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#53
In reply to #45

Re: Ok... the defense of the thesis

08/31/2011 1:47 AM

Brian - You need make no oral or other defense of your strategy or the rationale behind it. It is the nature of human beings to concern themselves with the future of their offspring. We are living in a era when all the social and cultural unknowns are supplemented by unknowns and even learned predictions of catastrophic changes in our environment. It is hard to argue with the wisdom of your strategy in light of all the unknowns we face.

But, into the details. I play the role of the engineer who focuses on the major technical obstacles. THE ROOF. Why the fixation on a roof that must be able to support agricultural activities? This looks like a big strain on the budget.

You do not state a need for concealment (for security reasons) which could otherwise be a reason to have the roof look exactly like the surrounding farmland and therefore be able to sustain loads typical of agricultural activities. If that is a real issue then it could support the direction you are going in. But absent that need a different roof could make more sense. Does the building need to be absolutely "underground". If that is part of a business plan, then OK. Is that the case? Perhaps some above ground signature is OK.

Humans have been building mounds for many millennia. They are still there right there in your neighborhood, remnants of the Mississippian culture of native Americans. The mound would be obviously unsuitable for tractors. The raised area between some reinforced concrete retaining walls with drains at ground level would be obviously unsuitable for tractors. Fill it with lightweight porous volcanic rock to hold weight down, facilitate drainage and provide insulation. Backfill outside the walls at an angle steep enough to discourage vehicles. Of course my suggestion here is just a swag. But it suggests many other alternatives.

This is an example of what I mean when I suggest getting to the root of the problem and clarify your objectives.

Ed Weldon

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#39

Re: Design Question for an Underground Home

08/29/2011 2:07 PM

Dear Brian: We have built a number of underground homes. There are a few things you have to know and be very careful of. The first one in insulation. If you care you can read a chapter in my insulation book. It is at static.monolithic.com/pdfs/rfairytale.pdf. Or go to my website www.monolithic.com and type in the little search bar "R" Fairy Tale. It is extremely important that you understand the section of this chapter on underground housing. If you do not the lesson if very expensive.. Most of the underground houses built in the 70's have been abandoned because of mold. You must understand the dynamics of the huge need for the insulation. Many times I have people say not so. They say the ground is 55 degrees and the house is to be 75 degrees and the occupants give of heat so they make up the difference so all will be well. And that would be true except for the mold. You must have the underground home better insulated than the above ground home especially if you are in warm and humid country. You can almost get away with less in the mountains of Montana. Please read and understand. It is heart breaking when people tell me of their woes.

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#40
In reply to #39

Re: Design Question for an Underground Home

08/29/2011 2:15 PM

Great first post!

I would imagine that the major issue with insulation is not the temperature gradient, but the ability for the colder ground to sink heat away versus open cold air.

It is much like when you submerse yourself in water that is 80° you will get cold after a period of time compared to standing in 80° ambient air, which will feel warm.

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#41
In reply to #39

Re: Design Question for an Underground Home

08/29/2011 3:31 PM

Read Post #27. My South Alabama underground home definitely deals with warm, moist air in the summer. I don't have your experience as a foam contractor, but I've got some experience in living with my own solutions.

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#42
In reply to #41

Re: Design Question for an Underground Home

08/29/2011 5:38 PM

as a concrete expert what do you think about using pre cast culvert sections as underground housing?

Here's an old school underground solution [it's more than a house]

http://www.undergroundgardens.com/

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#46
In reply to #42

Re: Design Question for an Underground Home

08/30/2011 2:32 AM

First, I'm not a concrete expert by any means, but precast culvert is expensive and limited in its capacity. Ever try living in a home with rooms no wider than 8 feet? It gets claustrophobic. Second, with respect to your link, he dug those tunnels before any serious regulatory overhead came into play. Try it today and watch how fast you get a "cease and desist" order nailed to your door. The age of Hobbits is over. The age of bureaucracy has come.

I don't mean to be rude, but only a suicidal fool walks into the pasture and pokes the Jersey bull with a sharp stick. Especially if he can't run, can't hide and doesn't have a large (loaded) rifle.

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#48
In reply to #46

Re: Design Question for an Underground Home

08/30/2011 9:18 AM

Too expensive

great answer

I didn't know the span was limited to 8 feet

the link to Forstiere Underground Gardens I think provides conceptual support for your thesis. The methodology doesn't apply

From what you have written, you are planning a community. A more comprehensive approach will provide many benefits beyond the increased efficiency of the plant [infrastructure]

I am in no way offended by anything you have written

Thanks for sharing

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#55
In reply to #46

Re: Design Question for an Underground Home

08/31/2011 5:57 AM

I've seen pre-cast concrete culvert sections up to 12 feet. I don't know the maximum size of the pre-cast units, but, I'm sure it's over 12 ft. The concrete in these sections is quality controlled and, of course, can withstand vehicular traffic and earth load. There would be no concern about driving a tractor or even an 18-wheeler over the structure. With air entrainment added, it may not need to be insulated.

Check with your local Department of Transportation to find some local suppliers. They could probably direct you to where some are being installed. And, openings can be provided when cast or they can be cut in the field. I believe it would really be worth your time to check out the cost comparison of pre-cast concrete culvert sections. It would certainly simplify the construction. A lot of times, simpler is cheaper.

Have some fun today

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#56
In reply to #55

Re: Design Question for an Underground Home

08/31/2011 6:14 AM

I'm not following this fixation on culverts. The usable space in even a 12 foot culvert is minimal, and cavelike, not at all what the OP looking for.

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#60
In reply to #56

Re: Design Question for an Underground Home

08/31/2011 2:04 PM

I had asked OP about using culverts back in #42

If the end use required heavy equipment above there could be some advantages to using such sections

the marketing to the community will make or break the long range success of the project.

look like a cult, get treated like a cult, especially in a post "Patriot Act" world

Overtly setting yourself apart from the community will tend to make it more difficult to do something different especially in the construction trades

The cost of construction & lower climate control expenditures are good

security & safety are probably a mixed bag, the site factoring in heavily

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#86
In reply to #39

Re: Design Question for an Underground Home

09/20/2011 6:08 PM

This man is 100% correct on the insulation factor.. There is a right way and a wrong way and the mold will destroy your health and home..Of course you could gas it with chlorine dioxide on a routine basis. Even our contractor who claimed to have poured 500 homes in 15 years gave damn poor performance. All that work had to be redone on my home..www.domehome.ca

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#52

Re: Design Question for an Underground Home

08/30/2011 11:55 PM
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#54

Re: Design Question for an Underground Home

08/31/2011 4:30 AM

I still think something flaky is going on - too much worry about security and family size.

Who has to worry about the cops breaking in all the time?

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#57
In reply to #54

Re: Design Question for an Underground Home

08/31/2011 6:41 AM

You wrote, "Who has to worry about the cops breaking in all the time?"

You are right. There are something like 8,000 crimes (robberies, home invasions, burglaries) on US homes every day (according to the FBI).

The number of police warrant break ins is far, far less than that. Almost all of those are based on solid evidence of a crime.

I am far more concerned about a criminal breaking in than the police making a mistake.

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#58
In reply to #57

Re: Design Question for an Underground Home

08/31/2011 11:21 AM

Totally agreed about the possibilities - however living underground stops thieves?

It may restrict their access but stop them - don't think so.

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#59
In reply to #58

Re: Design Question for an Underground Home

08/31/2011 11:50 AM

It is a two edge sword.

On one hand it may improve security by reducing entry points. There have been homes and businesses burglarized by sawing through the roof and walls.

The flip side is that you may be trapped in your home if caught in a home invasion, fire, or flood. With an above ground home you at the least have options to escape through the windows.

The same goes for rescue. We have stickers that can be placed on windows called Tot Finders that indicate to fire and paramedic rescue personnel where children might be found.

Even elderly people are sometimes unable to respond to well-being checks and require entry by police or emergency personnel. I hear these stories in our own town. Family that live out of state can not reach their elder parents or grandparents for days or weeks. The police are asked to check on these people.

One growing trend is to provide entry methods for police and rescue forces by either leaving keys in special locked boxes or at neighbors so that first responders can save lives.

Florida has a lot of retired people that require special services for their life. You want to keep the bad people out, but not trap yourself in your own fortress where you perish in an emergency.

We have the same problem with window bars. They can keep people out or keep you in, trapped with a raging fire.

Cuts both ways.

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#61
In reply to #59

Re: Design Question for an Underground Home

09/01/2011 3:50 PM

***OFF TOPIC UK English Rant Warning***

Having said that, I genuinely would like a genuine answer to this question: why does US English feel the need to take the noun "burglar" and add "ize" (sniff...should be an "s") to make a verb, when there's already a perfectly good verb "to burgle" to describe what a burglar does????

It's just one of those things that drives me batty...like saying orient (which actually mean "to the east") when one means orientate (to line oneself up with the destination/marker etc)

/rant off

Thank you for your patience

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#62
In reply to #61

Re: Design Question for an Underground Home

09/01/2011 3:54 PM

If I told you the answer was under the hood, err, I mean bonnet, of your car, would you believe me?

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#65
In reply to #62

Re: Design Question for an Underground Home

09/01/2011 6:56 PM

And I was looking in the boot trunk....

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#67
In reply to #65

Re: Design Question for an Underground Home

09/01/2011 10:08 PM

That works if it is a 911.

The looks when people see me pop the "boot" on the front of the car and drop in groceries - priceless!

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#63
In reply to #61

Re: Design Question for an Underground Home

09/01/2011 4:05 PM

Orientate is an affectation. It is a made up word to express the act of performing orientation. To locate yourself is to orient yourself. To help others become familiar with their surroundings, you make a presentation of facts, an orientation.

I know no one who presentates. They either present, or make a presentation.

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#64
In reply to #61

Re: Design Question for an Underground Home

09/01/2011 4:13 PM
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#68
In reply to #64

Re: Design Question for an Underground Home

09/01/2011 10:31 PM

How about adding to each graph the origin and usage of "burglar", especially if it predates the two verb forms?

Ed. C.

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#69
In reply to #68

Re: Design Question for an Underground Home

09/02/2011 10:39 AM

Why worry - statistically it's nonsense taken in an American only demographic for American self proof.

We know perfectly well American is a ludicrous brand of Irish/German.

E.g. Germanic 'zee' - there is no French word for entrepreneur - they can't pronounce basil, oregano, tomato, think the tower and the food are the same word ... or spell aluminium ...

Nor can anyone English, educated in England, in English, be as literate in English, as an American - Statistics are Proof. Or should that be Ztatizticz?

May as well give up

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#70
In reply to #69

Re: Design Question for an Underground Home

09/02/2011 10:46 AM

Literate American?

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#71
In reply to #68

Re: Design Question for an Underground Home

09/02/2011 11:04 AM

I could not find any stats on usage. This is the best I could find:

Origin:

1225-75; Middle English < Anglo-French burgler (compare Anglo-Latin burg ( u ) lātor ), perhaps < Old French *borgl ( er ) to plunder, pillage (< Gallo-Romance *būriculāre, equivalent to *būric ( āre ) ( Old Low Franconian *būrj ( an ) to dart at, pounce upon + Vulgar Latin *-icāre v. suffix; compare Old French burgier to strike, hit) + -ulāre v. suffix) + Anglo-French -er -er2 ; see -ar2

World English Dictionary

burglar (ˈbɜːɡlə)

-

n

a person who commits burglary; housebreaker
[C15: from Anglo-French

burgler , from Medieval Latin burglātor , probably from burgāre to thieve, from Latin burgus castle, fortress, of Germanic origin]

burglar

1540s, shortened from M.E. burgulator, from Anglo-L. burglator (late 13c.), from O.Fr. burgeor "burglar," from M.L. burgator "burglar," from burgare "to break open, commit burglary," from L. burgus "fortress, castle," a Gmc. loan-word akin to

borough. The intrusive -l- is perhaps from influence of L. latro "thief," originally "hired servant." The native word was burgh-breche.

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#66
In reply to #61

Re: Design Question for an Underground Home

09/01/2011 10:00 PM

Because we Yanks sometimes bunglarize our word constructions?

--Ed. C.

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#72
In reply to #61

Re: Design Question for an Underground Home

09/02/2011 4:05 PM

As long as we are 'aring' our linguistic pet peeves - I know all Britts don't do it, but some have a nasty habit of pronouncing 'R's where they never were, and don't belong. Since when is bannana spelt with an R?

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#73
In reply to #72

Re: Design Question for an Underground Home

09/02/2011 6:42 PM

I think those are New Yorkers you are talking about. :)

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#74
In reply to #73

Re: Design Question for an Underground Home

09/02/2011 11:19 PM

When one hails from Texas, there is no significant difference between a New Yorker and a Gritt- they are all from back east...

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#75
In reply to #74

Re: Design Question for an Underground Home

09/03/2011 8:49 AM

Please don't lump downstaters from NYC, Westchester County and Long Island with upstate New Yorkers....we talk entirely different languages!!! LOL

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#76
In reply to #75

Re: Design Question for an Underground Home

09/03/2011 6:42 PM

OK. Let's see- NYC is just east of Texarkana...Where would upstate New York be- somewhere between Dallas and Canada?

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#77
In reply to #75

Re: Design Question for an Underground Home

09/04/2011 12:15 AM

What can be a reasonable time frame? Would like to come before you all live in underground containers and have lost the capacity to speak in a communicative way.

This is not personal. I just wanted to fit my opinion somewhere here between.

What are the provisions in the project to remain healthy in spirit and body? Mens sana in corpore sano? The pioneers slept almost outside and created a strong race. How is dealt with sun light underground? One light in the darkness: starting from the worst (concept) it can only become better.

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#78
In reply to #77

oh my aren't we sensitive

09/04/2011 12:49 AM

seems like OP left the building

one of the less than glowing critiques probably hit truth a nerve...

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#79
In reply to #78

More questions.

09/04/2011 3:19 PM

Sensitive? No.

I wasn't that interested in following the linguistics discussion,

As far as the critiques, the only one that made sense was Ed Weldon, who kept asking me to quantify issues related to the roof. That had me go back and re-evaluate a number of issues (most important was whether I'd fallen in love with an idea past the point of efficiency).

The end result was that I'm comfortable that the overall parameters provide a very cost-efficient and liveable structure, and the ability to do a lot of the construction in a shop environment adds to the labor and material efficiencies.

Having said that, a couple of questions arose concerning the wall construction. What I plan to do is use corrugated sheeting (removed from the containers- the roof, for example) as form material for the perimeter wall. The cross-section below gives the overhead view of what I'm talking about. I'd begin by bracing the outer form sheet against the container wall and drilling through both pieces, using eight-foot long, one-inch by 1/8th inch strapping material that had already had appropriate holes punched in them as a drilling guide.

With the holes drilled through the two sheets, I'd then pull the outer sheet away from the container the appropriate distance (thickness of the wall) and run pre-cut lengths of rebar through the holes and weld them (inside and out) to the 1" x 1/8" strapping. Since the walls and roof of a container are made of 2mm thick steel, the strapping material provides support and external bracing, minimizing the amount of shoring required when the form is filled with concrete (with a few gussets to ensure stability, the form is now part of the container).

Thus, the end result is something like a nelson shear stud that also holds the outer form attached to the container. That means the WWR must be placed and tied in at the appropriate distance from form walls prior to the outer form wall being attached. After the outer form is attached, it can be mostly covered with the appropriate amount of foam insulation, leaving a clear space at the top and ends which can be filled after the containers are in place and welded together.

That leaves only the vertical rebar which needs to be tied to the rebar in the foundation. My plan at the moment is to place the container in the correct position, but on blocks about 3 feet off the ground. Insert the vertical rebar down through the form from the top and when it's tied in to the foundation rebar, remove the blocks and lower the container into place.

Question #1: In Europe, it is common to weld rebar splices together, yet in the US it isn't. What would be the effect of welding the vertical rebar together, since it's purpose is primarily compressive in nature in this application? Wouldn't that benefit the compression strength by ensuring a better connection?

Question # 2: In the graphic above, I have the corrugation of the outer sheet opposed to the sheet that forms the wall of the container. I could just as easily have the corrugation match. Which would be better from a compressive strength standpoint- matching or opposed? Which would be better for resisting lateral pressure?

Question #3: CapMoosie suggested that the perimeter wall should be thought of in terms of being a retaining support wall. What is the effect of the corrugated steel encasement on the soil pressure resistance? Surely it must add to the integrity of the structure, but to what extent? How much additional compressive strength would this add as opposed to a "normal" concrete support wall?

Finally, sure to be near and dear to the hearts of all, I bring up the subject of finding a "good" engineer. Since, by definition, a licensed professional engineer is just as qualified as any other licensed professional engineer; and since by definition engineers engage in a mathematical-technical voodoo requiring years of study to master and said voodoo is for the most part incomprehensible to laypersons... at some point only another engineer in the same discipline would be able to evaluate the true competence of any given engineer. However, this is not allowed by the canons of professional ethics... because the licensing board says that anyone in possession of the license within that discipline is qualified.

Given that underground homes aren't common and the vast majority of underground structures like I want to build are military or government (I doubt I have the necessary security clearance to talk to the engineers with KBR or Halliburton), how does one find an engineer with some experience building underground structures? Do engineers consult? If I found a structural engineer with experience in underground structures, could I have a local engineer work with that person, knowing that the local guy is only being paid to put his stamp on the plans?

Really, this is a simple project. The structure has a load-bearing perimeter wall and two interior load-bearing walls. I want to support the roof and a 2-3 foot load of dirt on top of that. How hard can the calculations for foundation, walls and roof really be?

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#80
In reply to #79

Re: More questions.

09/04/2011 3:41 PM

Gosh, they build a lot of earth berm homes up north. Seems that you should be able to find someone that knows someone that designs them.

The preverbal "Yellow Pages" on the internet would be a good place to start. Call and ask questions and get referrals from these people if they don't have all the answers.

In the end you will have to deal with local codes and ordinances, so you will need someone licensed in your area who is willing to take on the job.

As a last resort you can take on that task yourself (for residential work), but will have to submit all your plans to a planning board and be prepared to back up all of your work with the right math and address all the codes. Essentially, you will need to become an expert. It is analogous to acting as your own attorney and it is a lot of work.

Personally, I would do the first pass of that work, then throw it into the lap of a licensed pro and let them finish the paperwork, which includes filling and getting all the building permits. These guys know all the people on the inside and how to make things happen. It is their job.

This is how I have done small projects in the past and I have a somewhat larger one in the works followed by a complete home some day in the future.

This way the licensed architect takes the risks and that is what I pay them for.

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#82
In reply to #80

Re: More questions.

09/04/2011 6:32 PM

Garth: We have to remove the roof sheeting on all the first floor containers to facilitate welding the container together from the inside and to access the floor supports above. That will get covered with drywall in due time. For the containers that are side by side, the two adjoining walls will be removed to create a space that is 16 feet wide, so many of the containers will have both a roof and one side removed. I'm not going to let that go to waste and it seems ideal material to use for the concrete forms.

The intended use of the overhead space is to grow grass, shrubs, grapevines, whatever. The purpose of the earth on the roof is to provide a protective and thermal blanket. Yes, we could build a conventional roof and superinsulate, but part of the design criteria were that the homes withstand tornado's, wildfire, etc., be environmentally friendly and not have maintenance costs. In addition, the concrete in the roof would be part of the thermal mass. A small woodburning stove could easily heat this house if extra heat was necessary.

Anyway, what the group's ladies have been lobbying for in the past week is smaller house designs... which resulted in me saying "OK, put it on paper and circulate some drawings. Run it up the flagpole and see if anybody salutes it." The current favorite comes in at about 5000 square feet with only a 20 foot span across the room at the center of the house.

It uses a layout of containers like this... which might appear to be 20 foot containers, but are actually 40 foot containers cut in half:

Using that layout, the first floor would look like this:

That long center gallery allows the windows across the front to let the light into the home and make the underground space seem larger and less claustrophobic. All that metal that's getting removed needs to go somewhere...

Anonymous Hero: Actually, the building code isn't an issue:

"The Kentucky Building Code 2007 is a uniform statewide mandatory building code and applies to all buildings to be constructed, altered or remodeled with the exception of farm dwellings or farm buildings and manufactured houses."

For a farm dwelling, you pay the fee and they give you the building permit. That's it. There is, however, more to the house than just the building permit. Your comment on getting the pros to handle the permitting process is well-taken. Been there, done that. The problem is that what I want to do is sufficiently out in left field that it creates problems for bureaucrats who usually say "NO" at any point of confusion. However, where the bureaucracy tends to be inflexible, there are loopholes.

For example: in order to connect to the power grid a new home has to have passed the inspections for compliance with the electrical code... but because this method of building meets the "manufactured housing" criteria... and the electrical system in manufactured housing is certified by the manufacturer... all the inspector does is inspect the hookup and meter base for compliance. Even that can be avoided, although it's technically not legal: If the electrical hookup was to a portable light industrial building used for a workshop (just guessing... but it would probably look a lot like a shipping container...) they wouldn't ever come back to check on it. If they did they'd just notice that the building had been moved into the side of the hill....

If we built off the grid (not part of the plan) and develop our own water supply (later), as near as I can tell, the only permit requiring an inspection would be for the septic system.

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#84
In reply to #82

Re: More questions.

09/05/2011 10:19 AM

looks like the Captain has most of the issues well in hand, including how to pick a SE, you are nearly looking for a partner

as tempting as it is to slide through the loopholes, be careful

mostly what bureaucrats object to is having to work hard, forcing them to do their jobs is not very popular. You need to figure out how to lead them by the hand & praise them publicly for the fine job they did. This is not much different than dealing with a typical manager, if you want to keep them happy figure out how to keep them at their desk you can't take them too far too fast too much new info will break their little brains, 2 minutes of truly new is about the maximum

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#87
In reply to #82

Re: More questions.

01/15/2012 8:43 PM

This has been a VERY interesting read, thankyou 'nobody special'. When you work out the finer details (including the roof span), let me know, and I will keen buy a set of plans off you. Or better yet, you can come down under and build me one. This design sounds brilliant. Even if its scares the mainstream, I highly commend you on the direction you are heading with the whole interdependent 'gated' farming community idea. It seems like a far better option having humans habitat the earth in this manner (rather than a high density consumer driven model we tend to lean toward at the present time), and still having mother nature available right above you to continue sustaining resources such as crops, and animal and plant life (oxygen) etc etc. Bravo, and best of luck to you with your future endevour!

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#81
In reply to #79

Re: More questions.

09/04/2011 4:49 PM

the wall reminds me of sheet pilings, which would save the large amount of work required to peel the skin off of the containers

what projects are built underground?

back the bridges, culverts, storage tanks

what is the intended use of the area overhead?

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#83
In reply to #79

Re: More questions.

09/05/2011 12:16 AM

Hello nobody,

I received your email late tonight, and came running right away....sort of. LOL

Let's look at your questions and hopefully come up with some good answers and recommendations.

Q#1: You certainly can weld rebar together along the lap splice as they do in Europe. However, I've never been a large fan of introducing any sort of high temperature to steel rebar, whether it is by electrical arc welding or torching, as it can possibly degrade the ductile properties of the steel and lessen the Yield Strength. Also, it can possibly impart brittleness into the steel molecular structure if not done properly. Welded rebar splices if they are located in a critical stress zone of the concrete element, usually requiring x-ray analysis to be performed along the joined rebar. Anyhow, ACI 318 still requires you to provide an adequately design lap splice.

An alternate solution to regular lap splices, especially the main bars, is to use mechanical fastening of the rebar. It is an expensive choice, but the weight and cost savings of using less rebar may balance out or could be close.....all a matter of economics of scale basically. IMO from a SE standpoint, utilize a mechanical fastener device that doesn't decrease the area and nominal diameter of either rebar like some devices that use threaded connections cutting into the meat of the rebar (unlike upsized rebar end threading).....they can possibly lead to failures if the root diameter and decreased cross-sectional area are not taken into account during the design/analysis process of a composite section.

Q#2 & #3: I was unaware that the container steel shells were only 2 mm thick. That won't add much to the structural resistance of the exterior walls. It may make a great form, but for all intensive purposes (to be conservative at this juncture) I'd consider them as "sacrificial" due to future corrosion issues, at both the interior (interior moisture/humidity) or exterior (groundwater and soil moisture per see) surfaces. Your future engineer may feel differently, but there are always multiple ways to skin a cat...

Another problem with including the corrugated steel in the calculations for determining the exterior concrete resistance is that there would now be 3 different materials in the wall instead of the normal 2 materials: 2 steels of differing properties (yield stress, ductility differences, and bonding issues, and the concrete itself. It's a messy calculation, but any SE worth his/her salt can do it with a lot of extra work. I personally do not think 2mm of corrugated steel on both faces is not going to help that much in resistance design vs. having a higher compressive strength concrete (say f'c = 5,000 psi minimum) that benefits you more, as well as utilizing ASTM A615 Grade 60 bars of proper size as the main bars in the wall (vertical bars...the horiz. bars will be needed for Shrinkage & Temp Steel).

After looking at your wall section I do have a suggestion to make in regard to main rebar placement. I would install the main vertical bars at each face and not a single row of main vertical steel near the interior wall face. This type of rebar installation is known as a "Doubly-Reinforced" concrete wall. Also, the use of decreased but proper concrete cover pursuant to ACI 318-08 will help immensely: in this case, since you're using permanently installed corrugated steel you can get away using 3/4-inch minimum concrete cover. The further you push the main bars out from the Neutral Axis (centerline) of the wall the greater your wall Design Resisting Moment (Mr) will be and therefore greater your ability to resist the lateral earth pressure and any hydraulic pressure that may become present throughout the structure's lifetime.

One advantage of utilizing the stacked containers is that you don't need to have the wall span the entire 20 foot height top-to-bottom. Instead, you can rely on the slab on grade, the 2nd floor, and the roof structure to help distribute the lateral loads imparted by the exterior walls; think of the wall as a continuous 2-span beam oriented vertically with the supports at the floors and roof lines. If necessary from a design standpoint and global rigidity of the structure, you can incorporate simple steel truss framing in the end walls of each container to case (transfer) the lateral loads down to the concrete foundation that'll be a part of the slab on grade, only beefed-up.

As far as the corrugations are arranged, I believe what you have shown would work the best. From a conservative viewpoint (at this time w/o cranking through numbers), I'd use the nominal wall thickness as the inner-most distance between corrugations, not the out-to-out distance. Those small "bump outs" provided by the corrugations won't gain you much in terms of Resisting Moment of the concrete wall......a lot depends on the actual geometry of the corrugations (width x depth, and any side sloping), but really, there isn't all that much concrete added to the overall scheme of things (much like corrugated metal roof deck or floor deck).

Your last Q (#4): You most likely can find a qualified PE who is a Structural Engineer in either the Yellow Pages or the online "Yellow Pages" who is located near to you or within a comfy distance. To find one that best fits your needs, ask other Contractors in your area, or a Contractor's Association that you belong to, who can recommend a few SE's that have a solid concrete design background. Also, meet each engineer and interview them. Have them make presentations or relevant concrete design projects that they've done that were successful. Make them work for you, not the other way around. It's your project and your money afterall. Follow-up with those project Owners and their Contractors about their individual experiences with such and such engineer. Beware of engineering firms that love to give an initial lowball cost of professional services quotation, only later on to nail the client w/a ton of extras, unless it was absolutely necesary due to a client-initiated or regulatory-initiated significant change of scope of services. And remember this, not all PE's are created equally. Being a Civil Engineer doesn't absolutely mean that they're a good or great SE, nor do they possess the necessary design/analysis experience and skills to perform structural engineering. ESPECIALLY CONCRETE DESIGN. I personally know a lot of CE's who are PE's, but could never consider them even a fair SE. Some CE's are practicing SE design and analysis outside their whelm of experience....and some of those people are what I would classify as outright dangerous. This may land me in hot water with the State of NY, but "I call it as I sees it". IMO, I personally think you would be well served by hiring a PE/SE who has designed a lot of successful deep commercial, industrial and government concrete foundations as well as hydraulic structures (water & wastewater treatment plants, incl. pump stations etc).

I could go on and on about this, but this is getting long and it's getting late...besides, tomorrow if labor Day and a pig roast to attend (after I lay down some more ceramic tile in the kitchen in the AM that is)!

Please have a super Labor Day, and don't hesitate to ask any more questions. I welcome helping you out. Good night.

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