Making Mud Bricks for domestic dwelling.

Hello Sparkstation

Thanks for the info. I have visited these sites (online) and will make contact with them ASAP. At a guess, I think that you may also be able to advise on off-grid wind powered domestic electricity generation to compliment a hybrid system that I propose to build. I am looking to build a 48volt system. I have considered using 2x24volt truck alternators as a lowcost, quick start supply till more funds available to build a better system. Any thoughts from you on same will be appreciated.

Thanks heaps

Desperate Des

There was a discussion not long ago here on CR4 on what I know as 'soil cement' blocks. There were several other names for the same concept: a mixture of local soil and something like 10% cement, compressed into bricks in a press of one form or another. I believe high clay soils make the best bricks... Look it up.

Hello dkwarmer

I will have to find that link. Thanks for your reply. Do you have other details of what you have found to be an appropriate mix of clay, cement,straw, lime and/or what ever other mixes that have successfully made mud bricks. I would appreciate your ongoing help. I am a city boy having a late in-life shot at a better lifestyle, and am prepared to work smart with the right amount of sweat & intelligent application with the right knowledge from the many to do it right, and am so happy to receive helpful advice from you & other more experienced players in this journey called life. Again, thanks. Will look forward with interest for your comments. I've surfed the net, & anyone with a thought generally wants my money for the pleasure of their experience, so your ongoing advice will be valued.

Thanks again

Desperate Des

I'm hardly expert - it's been over 40 years since I watched two processes in Chile.

1. Adobe: Clay and straw are mixed with water in a pit. A horse or similar animal walks around and around, rotating a stirring device. The mixture is then poured into wooden molds and allowed to air dry. On drying (a week or so, I think) the bricks shrink, so are easy to remove from the molds. They are then stacked into a long hollow pile, with dry brush filling the hollow, and covered with ordinary dirt. Some kind of a low chimney is fashioned at one end, and the fire is lit at the other end. As I recall, they keep the fire going for several days, then let it cool. The innermost layers of brick got the hottest, and are used for the most critical locations (around doors and windows), while the outermost layers are only used for garden walls etc. Total time to make one set of bricks is measured in months, and can only be done in the summer.

2. Soil cement: by adding cement instead of straw, and using hydraulic or mechanical pressure to form the bricks, The need for heating is eliminated, and with an appropriate roof, can be done year 'round (non-freezing weather). All the bricks should be of close to the same quality, if mixing and forming are consistent.

Good luck on your project!

Here in India we have plenty of Mud Brick making units mostly located in villages. They hire cheap local labour for moulding the bricks. These are baked in simple furnaces fired by dry grass. But we plaster these bricks with cement after walls are constructed.

Suresh Sharma

Hello Suresh

Thank you for your reply, it was very nice to get an interest from as far as India. Could you help me understand how the bricks are first constructed, what percentage of the composition is the clay, cement(if at all), straw, bitumen, lime etc. There are so many differing types being suggested, & I would be very grateful for your advice given the long & rich history that is India's & her peoples vast knowledge of what really works when constructing mud bricks. I would also like to see photo samples of the types of forms used to construct the bricks, please give me details of the dimension of the bricks used as well. All advice will be really appreciated.

With thanks

Desperate Des

You need to heat any clay brick to harden the clay. It may be hot enough to place them outside to dry but they will not be water proof. Clay products are not totally water proof unless heated to a temperature of 1,000 + degrees F. Depending on the type of clay will depend on the temp needed to set the clay. You could do a little testing to see how hard your clay will set with the heat of the outside in the sun to dry. Without knowing the chemical composition it would not be possible to give you a good answer as to formula or what would work to mix with it. When mixing your clay with water you must vibrate it to remove as many water bubbles as possible from inside the mix. The less air inside (water bubbles) the better it will harden.

Dear cnjr47usa

Thanks for the info. The Good Book says that "there is great wisdom in many counsellors".

Thanks for your insight. At the end of this journey I should have a good idea of whats' in front of me. Thanks again

Desperate Des

Try googling "Compressed Earth Block". There is a wealth of information available, including using either 5-10% Portland Cement, Fly Ash, or lime to weather-stabilize the bricks. There are a range of devices available for compressing the blocks, from a simple manual ram developed in Colombia in the 1950's to sophisticated hydraulic ram systems with a variety of mold designs.

Dear dkwarner

Much thanks. I do prefer the second option, it seems more managable to me.

Regards

Desperate Des

Dear cwarner7 11:

Thanks heaps for your reply. I will get straight into that site once if finish my thanks to you.

Regards

Desperate Des

I was part of the base closure team at George Air Force Base near Victorville, California (southern part of the state) in the early '90's. Out off the end of the flightline there were rev-up backstops (a noise reduction measure) that dated back to WWII construction. These were 3-wall square and 4-wall pentagonal open-roof enclosures the planes had been backed into for engine runups. The walls were some 12 - 15 feet tall, totally unreinforced, rammed earth (local dirt was alluvial silt/clay) formed between wooden planks (you could still see the marks from the plank edges). The walls were approx. 18" thick and apparently had no additives. Now granted, this is in the Mojave desert where annual rainfall is like 4" in two storms, but that's a long, long time for dirt to sit in one place in a pile.

Your knowledge of adobe is quite impressive, and I have gleaned significant insight into the process from your post.

On the other hand, Compressed Earth Block is a significantly different process than adobe, having originated some time around the mid-1950's in Colombia with a primitive device often referred to as the "Chiva Ram", designed for economically challenged construction in environments where adobe may not be an appropriate solution (i.e., tropical rain forests). The process has evolved to the use of hydraulic rams to significantly compress the material being used, apparently inducing bonding through the high pressures that is traditionally achieved through the application of heat. Based on studies done in New Mexico, it would appear that Compressed earth blocks are stronger (~4 times as strong in compression and sheer), better insulators (although there is, in the reports I have read, insufficient information to determine if these differences were the result of actual material differences, or "technique" differences), lower water wicking (much less void density due to high compression), and the process seems to work with a much broader soil specification. There is significant literature regarding stabilization with Portland Cement, fly ash or lime, but it is also noted that the insulation quality of the finished block is diminished for stabilized block. As with adobe, a proper surface treatment (properly maintained) would most likely do as much to insure long-term stability as chemical stabilization.

Compressed Earth Block is probably more like rammed earth construction than conventional adobe construction. The down side is the cost of hydraulic forming equipment, although good results have been demonstrated with manual systems such as the "Chiva Ram". The process requires much less energy than conventional fired brick, or even conventional concrete construction, and it does seem to be more appropriate to certain climate regimes than traditional adobe construction.

This Guy knows what he is talking about!

I also have been building for several years here in Uganda using "Stabilised soil" the biggest being a 60 bed hospital in Kanginima.

Just about every problem associated with the technology is set out in this answer.

First, let us differentiate between Adobe and "Stabilised".

Adobe is straight from the ground (with a little mixing) but nothing to offset the effect of water / rain etc. ideal in places like Arizona but not so good in a "monsoon" environment.

Stabilised means that something is added to offset the absorption of water so as the material retains structural integrity although to a lesser extent then when dry but still good enough to have a safe building. Hence the comment about water absolution tests and load testing in the aforesaid answer. As I said it IS a good answer.

Timbuktu has a building that is 100's of years old and 5 or 6 stories high (cant bring the name of it to mind but it is a very famous Mosque). It rains there once in about every 10 years or so and the first job after the rain is "Everybody out" and slap on another coat of mud which will then last until the next time it rain's!

The big problem with this technology and the main reason for little adoption is the fact that EVERY location has different soil "recipe" make-up and therefore there is NO set way to say "do this then do that".

Every place is a whole new "ball-game" hence "experience" is very much the deciding factor as to if you can make it work.

Having said the above - take the "easy" way out and use a "Dirt Bag" (sorry not being abusive - honest!) take a look at:-http://www.okokok.org/index.php

In your case if you wont something quick then this is the way to go - believe me you will have many sad failures with stabilised / adobe until you get the experience needed to build a "safe" home - start with the outside "dunny" first.

H

First, I would check with the local building officials about the building code requirements there in Australia, since I am sure the building codes are probably stricter in Australia than Uganda or Chad. Keep in mind the term safe is relative, and 1st world countries tend to have a slightly stricter definition.

ABSOLUTLY, Dear Boy!

Which is why I suggested the "Dirt-Bag" approach. As you will see, from taking a look at the quoted web site, the "promoters" of this method go to great pains to point out as to how this method has met US building regs etc. (I think US still qualifies as 1st world but I am open to guidance on this point)

Do we actually have any "enforced" building regs here in Uganda? News to me if we have. Any "enforcement" involved normally comes in the guise of a "back-hander" request!

Which is why we are SO open for NGO / "student intern" types to come and try ALL there quirky and hair-brained "off-the-wall" latest idea's to "Save Africa" on our people using them as local cannon-fodder "guinea-pigs" (unpaid of course).

As for Chad - Heaven knows, but having stood the test of time for about 1000 years has to amount to something I suppose.

But as I said it all comes down to "EXPERIANCE" and you can only get that by making mistakes.

Start with the "dunny" first was not meant in jest!

Thanks

H

Actually, as I am sure you already know, the building codes vary from State to State substantially in the US. For instance the State of California has stricter structural requirements for roof and foundation ties than Lousiana. Additionally, some of the various building codes used within States allow for exceptions by building officials to code requirements. So building codes with in a State can vary from City to City, though somewhat less in most cases. I would be really surprised to find any such earthen building structure accepted by the building officials of LA, San Francisco, or any major California Municipality. Thus my question would be which States and municipalities have accepted this building practice, as this is more telling. This is by the way one of the things i prefer about some of the commonwealth countries is the more standardized national builiding code.

Your comment made me laugh so much. You sure have a way with words Mr H.

Great advice. Simple as that.

Regards,

Earthman.

The most imporant thing is the clay minerology. You want the bulk of the clay to be 1:1, like Kaolinite, however you also want a small percentage of 2:1 clays for bonding, like montmorillonite or hydrous illite. 2:1 clays are highly expansive, and subject to very strong expnsion and shrinkage forces, so you want to limit these to avoid cracking of the brick, but want some in the mix to increase bonding strength. some clay soils just are not suitable for production of bricks, i.e. sodium bentonite deposits.

Right! O/K! You've made me get up out of me chair!

If your really serious to get into this "Mud Thing" start by getting hold of a book called:-

"Small-scale manufacture of stabilised soil blocks"

Technology Series - Technical Memorandum No12

Published by the International Labour Office, Geneva

ISBN 92-2-105838-7

ISSN 0252-2004

First published 1987

Written in words of one syllable that even I could understand.

This is the book that got me started and I aint had a building fall down yet (touch wood)

GATE - GTZ also did some reasonable books on the subject also but they tended to use words a bit more complicated, which lost me a bit!

Haven't searched the web to find if there is a copy around but there should be many gathering dust on failed NGO shelves somewhere.

Thanks

H

Check out the new site http://www.buildingnaturally.info It is a wiki site so feel free to enter your information and link to the correlating page on your site. We need more site builders to enhance it's current state.

I found the following at http://missiontour.org/related/adobe.htm

The soil you want for adobe is a loamy sand material as described in this table...