Thickness of Reinforced Concrete

Maybe measure the o.d. and the i.d., subtract, and divide by 2? Or is there any opening at all where you could make up a U-shaped "caliper"?

The entire basement of the home is completely finished. All my information is gleaned from inside the mechanical room. As well as looking into any voids behind the finished walls. The outside walls are veneered with brick. I do not know the thickness of the insulation, if it has any,or the size of the air gap. I am pretty sure they would not appreciate me plunging in a depth gauge into the interior walls. That leaves that out.

All though, I have several nice out side calipers of various shapes given to me by a retired machinist from England. None will apply as there is no access.

Thank you for the feed back.

This is just me trying to learn more.

My guess would be, between 8" and 14".

Men often built structures that served well as a "man cave" or "poker room". The only justification was, if the Cold War turned hot, they would have a safe place for the family to hide in case of nuclear holocaust.

Many, many good times were had in these structures.

That puts me sort of close. As far as the "Man cave" You appear to be spot on. There was a distinct segregation of the upper and lower levels. The more stairs I descended the less of the annoying kitsch I saw.

The center area had a massive wood burning fireplace. From the masonary style, the builder had to have brought a masson in from Quebec. That style is very distictive and I love it. This went along with the appropiate items, such as sports memorabilia. I do feel sorry for the man as he still supports the "Toronto Maple Leafs". Then came the billyards table and the shufflebord one. Do not start on the Bar area.

I covet, not the house. Just the basement.

The thickness of the concrete doesn't come in the first place, but the steel that is inside. To find out the thickness of the concrete: how do you get in the basement? There you should be able to find some indications. I spanned that distance with 3,500 psi and 9 inches, on top 3 inches for chappe and tile. Did the same but 12 inches for a 4 story building. Epicore below and rebar #5 squared to 1/2 foot.

Greetings Icarus

Why Don t you Take a "stout" Hammer Drill fitted with a long but small O.D. conrete bit

(3/16 in) and bore a hole in the concrete?

The odds are in your favor that you will "miss" the rebar, and if you don t,than you can relocate the hole when you "feel" the steel

I thank you and all others for responses. As I stated all I wanted was an educated guess, as I was just curious.

As for a test hole, not a chance. Sorry, I did not mention the buried electrical conduits in the slab.

Hmm--then this project was DOA even before the get-go. (Think about it.)

There was no project to DOA. As I stated before I was just curious and wished a best guess.

If it hollow core slabs with a topping then it is probably 10". If was poured as a 'wet deck' then it is probably 8".

I've built dozens of each and the only one that was thicker was a house I built for a German who wanted everything nearly doubled. His floor was a 13" thick wet deck with enough steel in it to clear span 25' in the living room.

I deal a lot with core slab buildings. This is not one off them. The only visible area of the ceiling is in the mechanical room. They used lumber for the forming.

Note I do like core slabs, as they have totally predictable reinforcement locations. Handy voids to install things, and dedicated fasteners available.

Thanks

If the builder was simply trying to build a concrete house (not a bad choice if proper planning and time is put into it), you probably wouldn't need more than an 8" wall with the appropriate rebar. If you wanted to build a bomb shelter, the walls should be a couple feet thick. If it was my house, I would have done 1' thick walls if I wanted it to last and did not know about ICF's. In this day and age, I would not contemplate anything other than ICF's for this type of house, and if I wanted a bomb shelter, I would do 12" (of concrete) ICF's, then do a formed foot or more thick around the outside of that as well. Lots of Rebar, then let the outside take the bomb hit and the inside would be cushioned by the insulation on the outside and held together by the insulation sandwich, but I digress...

You ought to be able to tell by looking at the doors, windows, or doing the divide by two method whether the walls are a foot or less vs two feet. Subtract out 7" for the interior studs (if on both outsides) and subtract another 3" for the firring strips that were likely run horizontally at 3 places up the wall to hold the studs to the wall. The bricks on the outside are easy: Find one at the corner that will show you the thickness (usually 3.5" for standard brick - but who knows what this guy used). He probably had 1" of insulation buried behind that, but should have had 2" if he built in a heating area of the country. This should give you an idea what the builder did. If the math gives you too small of a number, the guy probably laid furring 2x4' on their flats horizontally (or maybe vertically) then screwed the drywall to them direclty affording an extra 3.5" worth of concrete in the same give wall thickness.

Sounds like a pretty cool house, and I would totally love to have something like that. My wife would have nothing to do with it, so I have a "Traditional" house upstairs, and the Man-Cave downstairs with 13" thick ICF walls (8" Concrete) and roughsawn wood downstairs with massive window sills and door set-ins. It is so totally cool that I still can't believe I built it six years later. I love it and they will carry me out in a pine box - I am never leaving of my own accord! Two shops help, especially since one is inside the house and AC/heated to 70 deg year round, while the other is attached to the basement under the garage and is over 1000 square feet of heat-able bliss.

Remember, too, that if the house was built as a bomb shelter, they only NEEDED a PART of the house built as a bomb shelter. They were designed as a doomsday protection, not necessarily a place to spend eternity. Many were only 6' x 6', so if this guy only had one side of the basement (40' x 40') he had much more of a bomb shelter than most. If the entire basement was built that way, the guy had 40' x 120' to rattle around in, and he could still get away from the nagging wife with two walls and three separate rooms!

I always have fun contemplating why people invested in things they invested in when they build buildings. That is why I could never live in a cookie-cutter house in a housing development. Originality is what makes a house a home, and living in the same space as your neighbor leaves little room for originality. If you are contemplating building something unique for yourself, I say go for it! I recommend ICF's if you want to do concrete construction, and if you plan right, you won't need anyone to come in and cut anything for you (I have not even needed a core drill, yet for my house after 6 years of nearly constant construction). If you want help in the design phase or building phase I say find it and run with it. I would be happy to help in any way possible!

I hate to admit it, but I think I missed the actual question. Floor thickness. This will be largely dependant on the rebar in it, but to have a 40' span, suffice it to say there is a bunch in there, and there is a double mat. Probably 9" to 12" thick. Double that if a bomb shelter - maybe more. I have seen bomb shelters with 3' roofs, and they were only 6 or 8' x the same.

I have done a 42' x 88' building with 250 psf loading, and that had 10" thick floors, double mat of #5's. Three inch thicker at the interior posts, which were two across the 42' width. Of course, this was an industrial building, and it was 4 stories - 88' tall (hence the interior posts), but it was also not bomb proof.

Again, if I am going to do something like that myself for a private residence, I would use Hollow core concrete plank, with a concrete cap on it. 40' span would probably requre a 12" plank, but they make them up to 15" thick, then they go to t's and double-t's. If a bomb shelter, put down the planks, a layer of insulation, and a couple feet of concrete on top of it with two mats of rebar (min). You would probalby have to shore it downstairs until the concrete cured, but there would be no movement in the floor when you walk across it! Pricey... Without the bomb-proof requirement, you can get by cheaper with the spancrete than you probably could with a poured floor. You still have to cap it, but there is no rebar needed (use wire mesh or fibermesh), and the placement is much easier. I did that as well with my garage area (30' span <8" plank> with 4 vehicles sitting on it), and I have no regrets there, either.

You and I think alike. I just love to be different, as well as build it my way!

Alas: If I could, I would send the local planing department in a to tizzy.

Based upon yours, and previous posts, along with the center portion having a glass wall, it would never made it the bomb shelter stage.

Unless there is something I have not noticed, below the grade slab?

Thanks

Reinforced concrete walls tend to range about 7% to 10% of height. If they function as supporting columns or retaining walls they can be large, the thickness of retaining walls can typically be up to as much 12% of the height of the wall. Plus depending on structural/architectural function of the wall they may have a minimum size requirement, many concrete walls are constrained to a minimum thickness of 12 inches.

The answer to your question, "HOW THICK DO I THINK THE CONCRETE BETWEEN THE LOWER AND UPPER FLOOR IS", It cannot be determined with out exposure of the edges or the invasion with a drill. However one might estimate the thickness by "Brilliant deduction" sometimes also referred to as a "wild ass guess" based solely a reduction principal. From the outside of the building or possibly via an open stair well, measure from the surface of the lowest floor to the ceiling surface on the upper floor. Save the number. Then measure from the floor to the ceiling for each of the lower and upper rooms. Add these two quantities together and subtract the combined numbers of the separately measured heights from the overall height measured from the stair well, if you were lucky, or from the exterior if you were not.

Allow for furring on the ceiling of the lower floor ceiling if determined that it may be present and sleepers and flooring on the floor of the upper room if likewise determined that it may be present. The difference will be your assumption as to the thickness of the ceiling/floor concrete/reinforcing material.

TMF

Hello

As I have ruled out any access, to any exposed edges. And destructive testing is a non starter.

My original post, stated that I was just curious. This is the first time I have come across a non commercial, single family, bungalow home of this type. I further stated that I had no intent in being involved with any cutting and coring of the floor, as that is well out my field.

Based upon my first post. The "wild ass guess" guess is what I was looking for.

I just want to learn, comprehend, understand, a basic understanding, a rough idea, etc. of anything what I already have not already mastered. Even that is open to improvements.

What can I say: I just like to fly to close to sun.

Thanks for the time.

It's at least double the width of the sill plate. Probably 8 inches.