how do you make bricks?

[Mia]

since we have a life time supply of clay, my husband plans to make bricks, if we can find out how.  maybe we will use some of them for a short retaining wall.  or raised flower beds.
and how do you make "soil-cement," and what can you do with it?  (I'm not building a home out of it, but maybe the pump house.)
thank you for any information.

[Amanda_931]

I keep back-spacing and losing my carefully thought out   message!

All of the unfired clay or more likely sand/clay with or without straw may be made with soil cement.  somewhere around 5% concrete, or in the case of adobe, asphalt emulsion.

Compressed earth bricks--think Cinva Ram, although some of the engine powered machines make blocks that can be stacked onto the building immediately.  You can buy plans/contact someone who does--or did-- sell completed manual machines)

http://www.dirtcheapbuilder.com/cinvaramplans.html

If you wander around in that site you will learn even more than you wanted to know about earthen building.

Adobe blocks are molded--with straw.  Need to be dried.

Cob, currently fashionable for small houses that are works of art, is sand/clay/straw added and shaped on the building presumably on layers that will take the weight without slumping.

Brick needs to be fired.  The inside of Glenn's oven may be terra-cotta by now, but in order to produce enough bricks to do anything with them, you'd need a kiln.  Which could indeed be some sort of earthen dome.  Surely needs to be a fairly high unshrinkable mixture, although at least with pottery clay one adds ground fired clay instead of sand.

I'm having to buy my clay.  So I envy you yours.

[glenn kangiser]

Depends on what you want, Mia.  Simple adobe to more complex stabilized and combo interlocking adobe with a stabilized surface can be made by you at home.  

The formula for most adobe - soil cement etc. is best at around 30% clay 70% sand including the sand or aggregate that may occur naturally in your clay.  Add chopped straw to taste as Becky Bee says.  I use about 5 handfuls per ten shovels of material-- not real critical though.  Make a mold out of 2x4s the shape you want - fill it with mud - pull the mold off - go to the next one.  For stabilized - that won't wash away add cement about 7 to 10 percent, or Henry's 107 asphalt emulsion - or SS1H road sealer also an asphalt emulsion but cheaper - formulas range from 4 to 10 % on up to 30 percent for a floor surface mud.

Mix with your feet in a hole or on a tarp or a mixer or tractor- Bobcat or any other convenient method.  Tractors etc for large amounts.  Similar formulas for rammed earth usually with cement- without straw.

Taylor publishing has info on this stuff.  http://store.yahoo.com/dirtcheapbuilderbooks/adandearbuil.html

Molds can be made in gangs with handles and wheels to lift and raise and move to the next set.  We were in a mine entrance in Mexico where they were storing their bricks to dry.  Unstabilized adobes need a roof on top to keep the rain from softening them.  They can also be plastered with a water resistant surface.

I have made soil cement with clay and about 10% cement.  Mine doesn't wash away with water but is better with sand and straw.  Cut straw along the ropes with a chainsaw before cutting the ropes to easily chop it into shorter lengths.  

Cob is adobe built in place.  Becky Bee has been good enough to provide much of her book online. http://weblife.org/cob/


Adobes are usually made from soil where there is not extra sand available-- the straw holds the clay together - there is much more shrinkage than clay with sand but the bricks allow for the shrinkage.  Cob -rammed earth or adobe should be placed on top a waterproof surface such as concrete- rocks -or I have even heard of plastic being used although the  Chew Kee store is about 150 years old and used nothing but rammed earth for the foundation with repairs being done at the surface area as necessary - -Lime plaster - earth plaster with lime or cement and lime stabilized will help protect the surface underneath - moisture in any of it freezing can damage the surface requiring annual minor repairs.  Stucco or heavy cement plaster is not recommended as moisture will get trapped behind it.

[Shelley]

Sounds like you need a proper brick for your intended use.  Moisture is not the friend of regular adobe or cob or whatever that's made from dirt.

I went up a holler in Alamos, Sonora  where they were making what's known as burnt adobe.  A fired brick.

Very low tech, but I imagine that there's a learning curve to get the proper setup.  Had a low fire of wood coals going, bricks on edge piled around the fire, galvanized roofing on top of everything to keep the heat in and make a furnace.

They said that they fired them the better part of 24 hrs.  Imagine that the trick is not to let them dry out too fast and crack.

[Amanda_931]

also not let them cool too fast.  That'll crack fired ceramics too.

lots of people are making cob walls with some sort of little roof on top.

Ianto Evans had to re-do his plaster on an un-roofed wall, I understand--seems like Charmaine Taylor has a picture somewhere on her site.  Her bench has been outside in Northern California for years, IIRC.

[bil2054]

The literature on the subject of adobe has so many conflicting opinions!  Some say straw is not needed, and actually contributes to cracking, etc., some say you just can't make bricks without straw.

The moisture problem is dealt with by roof overhangs and/or additives, as Amanda mentioned.

What I have read about burnt  adobe brick is that they  spall easily.

My choice is the CEB, or compressed earth block.  They are less labor and water intensive to make, and don't need to cure so long.

For anyone interested, these folks make a Cinva ram, as well as air over hydraulic presses.  The most economical production units I've found so far.

http://www.ferncometal.com/

I like the idea of adobe. It is a building material within the grasp of anyone, and with maintainance, will last centuries.  It also requires less energy to produce, and no air pollution.

[jb]

hmmm...I started reading this thread just out of curiosity, no intention of making brick any time soon...now I'm ready to scout the property for brick-making materials. Sounds interesting, wondering about using some of the formulas for sculpting some outdoor art strutures...kind-of like glenn's cat oven, I guess....

[spinnm]

Sorry Mia that we've gone off from your question...but Billie Bob, spalling depends upon the climate.  I'd also be worried were you are.

And, be careful of the machines unless you come up with a way to be quick or cover your walls.  The CEBs dissolve with just a small amount of moisture.  I've seen them dropped into a dry wall bucket as a test.  Gone in a minute.  Need to get them up and stuccoed over right away.  Just a suggestion.

[bil2054]

"If the brick is stabilized and well cured, placing the brick in a bucket of water, stream or lake can be a great way to show its water resistance to those who might doubt that soil can be used to build a good house."

That's from an article describing Habitat for Humanity experience with CEB:
http://www.networkearth.org/naturalbuilding/ceb.html
The critical factors appear to be the soil composition, for a start, and stabilization and curing.  
I guess it's like any other construction material; we've all read horror stories, for instance, about poorly built bridges, etc., where the contractor skimped on the concrete.

Anywho, I guess those of us on the adobe/CBE bandwagon thought to suggest a possible alternative to the expense and/or labor of building and fueling a kiln for firing bricks.  Admittedly, the unfired bricks would do best in our type of climate, eh Shelley? Dry heat, indeed!

[spinnm]

Maybe I mispoke.  The CEBs that I've seen aren't stablilized or cured.  They come right out of the machine onto the wall.  They melt.

I talked to some contractors just this summer who had purchased a machine and were building a million dollar house up in the Gila.  I asked them if anyone had figured out a way to stablilize them.  They said no.  

Are you saying that someone has indeed found a way?

[spinnm]

I get it.  Went to the FernCo site and poked around.  Capitan, NM.  Smokey Bear, Billy the Kid country.

Guess that you could stablize the block.  This is a one-at-time thing more or less.  Thousand bucks?  Makes one a minute.  Machines that I was talking about make them almost as fast as one can pull them off and are not for the one-off house.  Cost 50-70k

Guess it depends upon the time you have.  Can make a form out of 2x4s and pour your own.  That's what the yards do.

Just noticed your comment about straw.  If you're making adobe blocks, CW around here is that straw is passe, used in the old days when the proper mix of sand/clay was unknown or unavailable.  Addition of straw was done in high clay soils.  Prevented cracking.  If the proper mix is used (70/30) is not necessary.  This CW is blocks only.  Other uses may require straw....or some kind of binder.  You can buy, for instance, little chopped pieces of plastic that's used in stucco.  That would work just as well.  In my mind, it's just a binder.  Like rock in cement.

[jerry Hambley]

Here are some links that may be of interest:

http://www.adobebuilder.com/newsletter/july03.html

http://www.earth-auroville.com/index.php?nav=home

http://www.kubuildingtech.org/ngore//nilsweb/cinvablocks/cinva.html

http://www.terrablock.com/profile.html

http://www2.gtz.de/Basin/gate/interlocking.htm

http://www.mountain.org/work/peak/earthblock/machineinfo.cfm

[Amanda_931]

Thanks for the links.

Auroville and the BASIN links had gotten left on an earlier computer.

I just sent Auroville's page of Gaudi pictures to a bunch of people, looking around the new ? BASIN site now.  (I think I first encountered it before www2.)

http://www.earth-auroville.com/index.php?nav=menu&pg=vault&id1=18

For those of us in the Southeast, there's a mid-priced CEB maker in Decatur Alabama--not that far from me.  They claim 2 cents a block--but that's only if you can operate the thing 200+days a year for ten years.

http://www.defcoinc.com/Adobe/Blockmaker_Hox.html

[Amanda_931]

Some of my favorite stuff on earth building is on the BASIN site.  Especially the free stuff.  

Index page here:

http://www2.gtz.de/Basin/publications/index.asp?A=1

and a title I've posted somewhere a few thousand times (not really, but surely a dozen)

http://www2.gtz.de/Basin/publications/books/ManualMinke.pdf

This is the construction manual for earthquake resistant houses made of earth.

He (and some of his students) talk about shape, siting, an so on.  Not a bad thing to read about no matter what you are building.

And the price is right--waiting for the .pdf file to load!

A couple more titles--same price--building with earth blocks on the page.

CRATerre is a French earthen building site, and a partner in BASIN.  Fun to look around, even if your French is as bad as mine--hey, it's better than my German.

[glenn-k]

Minke manual is great, Amanda.  Thanks for the link.

A note to add to the above comments, bricks should be able to be stabilized with the addition of asphalt emulsion (SS1H or similar) at about 4 to 7% or portland cement at about 7 to 10%.  Mixing would be necessary but could be done in a mixer or with a tractor or bobcat in the case of larger quantities.

Cement is commonly added to rammed earth house mixes per David Easton I think it was.

Straw in the mix even with the sand seems to prevent cracking in stabilized earth plaster walls and hold it together.

[Amanda_931]

Someone on another list posted this--a slide show on brick manufacturing.  These guys supplied brick for shops in the Mall of America.  I guess they make lots of bricks.

http://www.ochsbrick.com/tour/Tour%2001.htm

[Peter Ross]

Well many of the brick recipees call for Straw, or Portland Cement...

People are fogetting that fresh Cow Manure is a Natural Cement...It is readily available everywhere and should be free if you look or ask a farmer.

Yes it stinks...but it is all natural.

I have a brick recipee somewhere, but I think it was half Clay..Half Manure...And the cure time was short

as for brick machines...You can buy them if you go to a machine auction...A place where combines, tractors, factory machinery is sold off...Go to a few of these and you will steal a brick machine...Yes they make something crazy like 1000 bricks an hour...Providing you have enough people to work it properly and the resources and machinery to maximize the machine.

I looked at the steel press...Anyone that can weld can make that press...It is a great idea...Long handle for maximum torque... You could weld one of them up for about $100 if you buy scrap steel at the local welding shop or salvage yard...

For a couple hundred bucks you could have a brick making press...And make a brick a minute...

If you use a little portland with the Clay and Sand...The cure time is not going to be long.....

I would say the key is to have a place set up in advance to store the bricks  that is dry....and plan ahead...Check for good weather and take a couple saturdays and make enough bricks for your garage or house- Let them cure and then start building.

If you have no money and are a 1 or 2 person operation you have to be patient and willing to churn out bricks at 1 per minute.

-Peter

[glenn-k]

Thanks for the posting, Peter.  As you mentioned, about 7 to 10% Portland cement added to my clay makes it hold up well in water and also causes it to set up in an hour or less.  Winter time would probably take longer.  Strength should go up from about 100 psi compressive strength unstabilized to around 300 psi per Ken Kern.  Added sand in proper amounts causes less shrinkage and more strength.  To meet code these bricks would probably only be allowed as some kind of infill in a post and beam frame or possibly in a frame with poured concrete pillars and beams.  This technique is shown in  The Rammed Earth House book.

Monolithic curving cob walls reinforced with straw are stronger than walls made of bricks.

[benevolance]

Glenn,

Your bricks are ready to bear load in one hour? With that apparatus anyone could really get into making a home themselves.

A few years back we just used sand, Clay and a little straw...And let the South Carolina Sun work it's magic...Not as hot as Arizona or California in the summertime...But plenty hot man it cures the bricks great!

For my next project I am thinking of Adobe like bricks...Huge blocks that are 23 3/4  inches long 11 3/4  inches high and 12 inches thick

And of course making these Adobe like blocks in a Press... Something like the Ram that was pictured in the links.

Whether or not to add Portland or a Curing agent is something to think about....The website that sells the Brick presses sells curing agent for $120 a gallon....If it works well and will go far it might be a sound investment...

If I am on a tight budget I just might use Sand, Clay and Portland....Make the blocks in a press...and then let them bake in the sun....Just to make sure they are cured and will be resistant to water and the elements

I want to build a 40 x 60 Workshop for storing some cars in...Half of the building will have an upstairs... 16 foot high walls...I figure I need to make 1400 Adobe Blocks

I will test my new blocks out on a camp first...And if I like the results I will use the blocks to build my workshop...

I cannot do anything about the cost of roofing tin, or the rafters.... But Clay here in the upstate is free for the taking...There are places where they have signs posted...back your truck in and load up...

So get a dumptruck load of sand...haul off some clay and buy 25 bags of cement...I figure it will cost me  a hundred to build my press...600 for cement and sand....I could have all my walls for the workshop for under $1000...

I would still have to rent a mortar mixer and buy mortar when making the walls...and I would likely hire someone to help me with a project that big...A local kid looking for some extra cash.

What they want for cement here....OMG! I could get it for $60 a yard in Canada...Which is less than $50 a yard in American Funds...Here in SC...I cannot find it for less than $90 a yard...

getting anything done here is retardlly expensive

-Peter

[glenn-k]

I wouldn't say ready to bear a load, and I do mostly cob but in warm times it definitely makes a big change in that hour -most of the time solid enough to step on without squishing in about an hour.  Even normal concrete takes about 7 days to acquire most of its strength.  The idea of making bricks is because if clay is low in sand content it shrinks much more.  By making the bricks you get rid of most of the shrinkage in the individual unit then only have to deal with the thin layer of mortar shrinking.  Earth building - cob -rammed earth etc  using 70% sand 30% clay shrinks less - straw is a type of reinforcing.

Bricks can be made with a waterproof surface and made interlocking as done in some places in India greatly increasing weather and earthquake resistance.  I had a site linked but they took that portion off their site the last time I looked.

[jraabe]

Some of my old Peace Corps buddies built a school in Iran using non-fired mud bricks with an additive that was some type of asphalt emulsion. It made for a sturdy waterproof mud brick that went together like the normal mud bricks but held up much better.

Don't know if the material is still available and if there are nasties involved or not.

[glenn-k]

Henry's #107 is asphalt emulsion and can be added to the mud at the rate of about 5% to 30%. Also there is one called Blackjack.   Test the bricks in water after dry to see if it is enough.  The higher mixing rate is used in the Rub-R-Slate floor surface mix I think.  Charmaine Taylor published or has some information on this.

I found an Adobe brick making site that used SS1H road sealer -an asphalt emulsion also as a stabilizer at the rate of 4%.  It is much cheaper than the Henry's currently under $2.00 per gallon I think.  Henry's is around $20 for 5 gallons.  I have used the Henry's - It works as stated-- the SS1H I haven't used.

If I recall correctly the asphalt emulsions are safe and non-toxic, but this does not apply to some of the other road sealers which use coal tar and should not be used in bricks or plasters etc.  The Henry's loses its slight asphalt odor when dry.

[jraabe]

As usual, Glenn's the man with the real info!

So very glad your here, mate.

[glenn-k]

Thank's John-- being here nearly keeps me out of trouble.