Rammed Earth Construction

Posted September 22, 2008

Rammed Earth Construction is the ultimate in building with local materials.  It is build from earth that is dug up from the building site.  The technique consists of building a form, similar to a form used to pour concrete, and then filling the form with a mixture of sand, clay and gravel with portland cement as a binder and then compressing it together with a tamper.

Rammed earth construction has been in use since the neolithic ages and there are archeological sites in China from 5000 BCE where rammed earth was used for walls and foundations.  In the past binders such as blood or lime were used.

Rammed earth construction is particularly good in passive solar design, as it has a large amount of thermal mass, which will even out the temperature fluctuation during the day.  It also has the advantages of being almost soundproof and fireproof.  In some sites, other materials, such as glass or shells are added to the mixture to give it additional texture.  It can also be coloured by adding pigments to the mixture.  Variations can be created by using different mixture in the various layers.  Since the rammed earth is used as the finshed wall, it is very non-toxic, as the materials are soil and cement, so it is a good construction method for those with environmental allergies.

The technique for construction is quite simple.  Forms are put in place in the shape of the desired wall and then a damp mixture of sand, clay, gravel and portland cement is placed in the forms four to ten inches deep.  The mixture is tamped down with either a mechanical pogo stick tamper, a pneumatic tamper or by hand with a plate tamper until it has been compressed to about half it’s original thickness.  Another layer is then put in and the process is repeated until the top of the form is reached.  The form is then removed and move up so the process can continue until the desired wall height is reached.

An interesting variation on rammed earth was developed in British Columbia, called SIREwall, which stands for Stabalized, Insulated Rammed Earth wall.  In their process, a piece of foam insulation of the desired thickness is placed vertically in the center of the form and the rammed earth is placed on either side around reinforcing rebar and then tamped down using custom selected mechanical tampers.  This creates a wall that has an insulated core, but has the thermal mass exposed on the interior and a durable rammed earth exterior protecting the insulation.  This results in a wall between 14 and 21 inches thick.  The SIREwall process has a protocol that controls the soil consistency, the method of mixing and curing to produce a wall with predictable, cost-effective results.

Properly done, a rammed earth construction will create a building that is weather resistant, soundproof, insect and rodent proof, inexpensive to heat and cool, very comfortable to live in and will probably last for centuries.

Posted under Techniques

27 Comments so far

  1. Lee September 23, 2008 6:26 pm

    SIREwall didn’t develop insulated rammed earth walls, only popularized it. Why is SIREwalls only producing highend houses? The fact that SIREwalls only produces high end houses leads me to believe that they are not cost effective. Form work is some thing else to consider, some projects have more materials in form work than would go into a traditional stick frame house, and it might be a one off.

  2. Ward Edwards September 23, 2008 7:33 pm

    The SIREwall system is more involved than just an insulated rammed earth. They have done several years of research to perfect the system and make it stronger and more stable. The system they developed is aimed more at contractors, so the materials for the forms are likely to be used multiple times on different projects.

  3. Joss Krayenhoff September 25, 2008 1:15 pm

    Hello,
    I am a SIREWALL Project Manager for SIREWALL. Ward accurately responded to most of the comments above. The one he could not address is cost.

    SIREWALL attracts many clients who want upper end homes as a result of our beautiful product. We have also done a number of local projects that fit into the local “low-cost housing range”. A SIREWALL home is typically about the same cost as a house with a concrete wall system, which is, 10-15% more then a house that uses “stickframe” construction. If a house cost $400,000 with stickframe walls, then, the same SIREWALL home would cost $440,000-$460,000.

    Lee, if you would like to educate yourself feel free to send me an email requesting more information.
    – We use a fraction of the formwork used in stickframe.
    – And we were the first people to develop an Insulated Rammed Earth System. There were people in the past who put straw bales, or something else, over the rammed earth to act as an insulating blanket.

    http://www.sirewall.com
    http://www.terrafirmabuilders.ca

  4. Lee October 18, 2008 2:24 pm

    I believe in an age of sustainability the idea of taking a product as old and beautiful as rammed earth and trying to patent it in the form of SIRE walls is pushing in the wrong direction. The green revolution should be one of open source green technology not companies patenting a technology. I would ask how do you respond to NAREBA and the website http://rammedearth.blogspot.com/, I would urge all readers of this to take a look.
    I believe you may be the leaders in N America but as far as I am concerned Australia and Europe are the real leaders, and believe they had started putting insulation in rammed earth. Sustainability should be for all, not the rich. SIRewalls slows the progression of rammed earth for Canada with it’s non competition agreements.

  5. David Lippincott November 2, 2008 1:42 am

    I have to disagree with Mr. Krayenhoff.

    SIREWALL is not affordable.
    I had to terminate Terra Firma builders from a local project because they could not stay within a reasonable budget.
    It was a simple design, basically a rectangle.
    We parted ways because of a projected 30% budget override. High quality work but definitely not affordable. $300/square foot turned into $400+. They have a lot of work to do in order to make it affordable.

  6. Earthman January 29, 2009 4:58 pm

    SIREWALL is not a really a rammed earth company. Like most RE claimants, what they are actually making is a soil cement or low grade concrete. I do believe those products to be beautiful and durable and functional, but real Rammed Earth has no man made stabilizers.
    Further, they present a somewhat skewed landscape of their implied ownership of earth building. I have also seen the recent pics of the Nk’MIP structure. They seem to show a less than desirable end product that is SIREWALL’s combined result of years of highly touted experimentation and their lofty charge per square foot.
    While I applaud their efforts in the area of earth building, their numerous claims and statements often do not hold up under professional scrutiny.

  7. Thomas Breitkreutz February 5, 2009 8:50 pm

    Hello,
    I am a student at NAIT college in Alberta. I am taking a program called Construction Engineering Technology. I am currently writting a technical paper on earth construction. Primarily I am focusing on rammed earth. I am looking for people in the industry who would be willing to talk to me and answer some of my questions about this way of building and its possible implications. If interested please email me at taz1500@hotmail.com.
    Thank you

  8. man of the earth February 28, 2009 12:52 am

    I think rammed earth is fantastical. Lot’s of guys in Canada are building with insulated rammed earth like these guys at http://www.rammedearth.info
    putting insulation inside a wall of whaterver material is not new
    so really S***wall is just a name that is getting way to much attention.

  9. Brad Esau September 26, 2009 10:09 am

    Very interesting thread and I thank and applaud everyone for their contributions, viewpoints and information. Most informative.

  10. Tom Jensen March 4, 2010 3:44 pm

    Very interesting comments in regards to the SIREwall system. I am a builder who was lead to believe that SIREwall would train us and give technical support to ” their ” system. 1) they never even tested their new forming system and every end panel had to be sledge hammered off the walls!! This is a company that had been in the business 15years at the time. Two years later and after receiving a lot of help from all the builders who took the failed course, SIREwall blindsided ever builder with a franchisor/ franchisee contract that we all considered DOA. If Meror Krayenhoff actually wanted 1% of North American housing to be rammed earth then he would stop trying to patent a system that has been in the UK and Australia for years and also stop ripping off every client that comes his way and start cooperating with the emerging rammed earth industry.

  11. nattancecilbro March 24, 2010 1:22 am

    Hi my name is Nathan and I am part of sirewalls low cost building initiative. Just through my own experience there has been thousands of hours of conversation with hundreds of people(no one was paid). I would like to invite anyone commited to the future and talking about ideas that work with North American standards to speak up and be part of the sollution.

  12. Jordan May 26, 2010 10:40 am

    Hey Guys, I am a student currently taking archtecture in ottawa. I am just trying to learn a bit more about rammed earth buildings and houses. I would like to learn more and am interested into finding out what you would need to do to start and finish a product like this. If anyone is willing to send me some info maybe a pamphlet or even a catalogue on what you have to offer, it would be greatly appreciated.

    THank you guys for your time,

    Jordan Labelle
    jordan.labelle@rogers.com

  13. Mark May 28, 2010 9:16 am

    Too bad all the commentary here is about one company. Are there other companies of note building rammed earth structures?
    A couple of things I’d be interested to know: Can rammed earth be used as a foundation? Can rammed earth slabs be used as driveways or walkways? What are the most effective binding agents not including cement? (The production of cement is not environmentally friendly)

  14. Earth Dwell Ltd. November 24, 2010 12:27 am

    Mark,
    There are other companies that do high quality RE projects, insulated and uninsulated as the project requires and I count my own, Earth Dwell Ltd. among them. There are others at http://www.nareba.org.
    Now to your RE questions.
    Rammed Earth (RE) would not be an ideal foundation material for the simple reason that it doesn’t make sense to ram a foundation. It is buried in the dirt and it makes more sense to pour a foundation as it is simpler. The forms required for RE must be very strong, particularly if the form work does not use unsightly through ties, as ours does not. It is also nice if the form work is aluminum based as there is a lot less wood
    wasted. It would be possible to use a soil cement for your foundation provided it was strong enough to support the wall above (and you could find an engineer to sign off on it). But I can’t imagine why it would be worth the trouble to ram a foundation as it is a lot of unnecessary work. You might look into a rubble trench as an alternative foundation if earthquakes are not a concern. It is possible to use RE below grade for retaining walls and basements. There are pictures of this on our website(www.earthdwell.com).
    As far as slabs, driveways and walkways; again it is very possible to use packed earth with cement or not as the situation dictates. But pure earthen mix without cement is obviously going to be worthless outside. I have seen an earthen floor in a house that used linseed oil and clay as a binder. It was lovely. There is a woman in Portland, OR named Sukita who specializes in earthen floors.
    As far as cement goes; it contains a great deal of embodied energy so its use must be weighed. It is very effective at stabilizing an RE wall. With RE it can be used in quantities that are a fraction of what is used in concrete and achieve comparable strengths. Is it worth using a small amount of cement in a wall if it extends the life cycle of the structure by hundreds of years? From a sustainability perspective it seems necessary. There are other binders that can be used to reduce the cement content but to get the strength necessary to withstand an earthquake and stand up to a wet climate some cement is necessary.
    I hope this helps.
    Bly Windstorm
    bly@earthdwell.com

  15. victor December 20, 2010 2:56 am

    Curently am a building student of university of JOS. Hold it or not; the topic in question is my project topic-COMPARATIVE STRENTH TEST ON COMPRESSED EARTH BRICKS STABILIZED WITH VARYING AMOUNT OF LIME AND ORDINARY PORTLAND CEMENT. Happy if i can get some materials like: journal, mannul or manuscript, from interested fellow to aid my research. Reach me at, Vicdayo1@yahoo.co.uk

  16. terry June 24, 2011 12:20 pm

    I would like to know footing sizes for a rammed earth wall and how to determine the frost line for the region that I live in?

  17. Ward Edwards June 24, 2011 1:49 pm

    Your best bet is to contact an engineer, or ask your building inspector what he/she would require.

  18. steve brown July 15, 2011 9:24 am

    hi i would like to get some information as to just what i would need to construct a ram earth house other than the earth itself. would just pitrun gravel be good and if you could tell me what the ratio mixture would be for the cement and weather i would need to mix it with water or just mix it in the gravel and go with that.

  19. Walter Daniel November 17, 2011 7:00 pm

    I think its great that no one edits out the complaints here, I am a bit confused that some one is trying to patent a packed mud formula that can be core sampled out of the great wall or any packed mud building site that pre dates Christ. Going open source would garner you as much support as that lil fad called the iphone app or google droid app.

  20. George November 30, 2011 8:05 pm

    Hello, great thread. Can anyone share what is the proper soil mixture for rammed earth i.e., how much sand, gravel, soil, cement etc.

    Thanks very much.

  21. James February 20, 2012 2:52 pm

    As a student of technology and a believer in being informed before I share my opinions/advice, I would like to offer the following to the complaints about SIREwall and the questions regarding rammed earth.
    Patenting the technology of SIREwall is about saying “this system is how we do it”, so when some DIYer decides to throw some dirt into forms around a piece of styrofoam, SIREwall can say they are different. Anyone CAN building SIRE walls, but not necessarily right. And good luck getting approval from building inspectors, engineers and architects; any idea how many North American jurisdictions have rammed earth building codes? Answer – New Mexico. When you kill your clients/self because you don’t need a developed technology, come back here and tell us how it went. Every builder has a project that goes over budget – name one company that hasn’t, and I’ll name you a liar.
    As far as mix rations, this will depend on a lot of things. Are there code requirements in your area? What has your design professional recommended? NEVER design structural components without being or consulting a registered design professional.

  22. Marc April 13, 2012 12:57 am

    I think all posters on this sit is mainly basing all their facts on a company . But it seems this is the only company that has credentials in building Re walls so why not give them a break .. I have a historical house that needs a fence, and I am thinking that a Re fence would be the way to go to get the aged effect . I dont wish to hire a contractor S I am one but would like to know the construction of it or be part of a company that has the know how to do so in my community . Forward your thoughts to marcracine@ hotmail.com.

  23. drew May 20, 2012 8:25 pm

    if i want to build a rammed earth house could i use a simple abase material to make the walls out of?

  24. Vredesbyrd November 18, 2012 8:41 pm

    Doesn’t anyone know how to do their own research now a days? GOOGLE the mixture ratio..YOUTUBE them, and experiment. LIVE DEBT FREE..(DIY,I know this was mentioned above, but you’re essentially making a rock 3 feet thick or more WITH A FOUNDATION, go to your library and research you’re not going to screw up. Professionalism isn’t really much of a concern regarding rammed earth homes.) You should really be creating these structures all yourself. It was common knowledge thousands of years ago, and in third world countries it is still today. Most of the worlds population are living in structures like rammed earth and cob its nothing new.. You have a vast network of knowledge via the internet. Be wary of all companies and contractors.. They purposely go over budget, *uck up, and screw around for more money. They are a BUSINESS not a compassion club.

    I think the type of people that benefit from RE most are those that try to live self sufficiently and off grid..If you’re not into that, why pay out the sphincters for what others get free via the community coming together and building it. Is it the creativity or lack of it that that feeds the need to get financially raped? Don’t get me wrong I care about the earth and the false global warming scam but this is ridiculous.

    Why do you SIREwalls charge so much? >:O You know if you really cared about the environment you could promote other solutions like indoor greenhouses, water harvesting systems, natural swimming pools,upgraded rocket stoves ect..

  25. Ward Edwards November 19, 2012 8:11 am

    The problem is that some people just have no mechanical skills, and so cannot do the building by themselves. They still want the building, so they have no choice but to hire someone to do it.

  26. Vredesbyrd November 20, 2012 7:50 pm

    True. Well anyways, you do a DAMN good job at what you do so keep up the good work! It would be nice to see a green revolution take place in my lifetime (of course without the carbon taxes and other politically motivated pitfalls). I think humanity has lost touch with nature. We humans constantly are fighting against and poising it without even trying to re balance the Eco-system or create a whole new one.. Its like the perfect natural machine. We definitely need more people to lead the way into a more natural life.

  27. Keith Elliott January 24, 2013 12:06 am

    Most interesting subject.
    Some years ago I delved into this rammed earth thing, and while it is true that it has been around for a coon’s age, I do think that we are able to make a better RE product today than 5,000 years ago. Some of the engineering reports I have read will show the modern RE wall to be unbelievably strong, it really does boggle the mind.
    One thing you do need to try and do is to keep the wall out of the rain. I suppose that with sufficient Portland in the wall that may not be a concern, but the ratio is far lower with a RE wall than with regular concrete construction. One thing you can do with RE is to make the wall extremely artistic. Some of those walls with the gorgeous colours running through them are just fantastic.
    In recent times – say the past 40-50 years, it seems to me that some hopeful builders were thinking that they could build a RE house on the cheap. Then building departments got in the way and messed all that up. Maybe that is why a RE house costs more than a conventional house these days on an equal square foot basis.

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