PAHS hyperadobe earthbag house by Earthen Hand Natural Building (click to enlarge)

PAHS hyperadobe earthbag house by Earthen Hand Natural Building (click to enlarge)


“Earthen Hand Natural Building recently has created an 800 sf earthbag house on the Olympic Peninsula in Washington state. Passive Annual Heat Storage (PAHS) design features were used in this building, giving it the ability to heat and cool itself passively using the earth beneath the building and the walls themselves as a battery of heat. This technique has been around a long time and has produced some amazing results. This building will also incorporate a south-facing greenhouse, greywater system, and solar.

A standard rubble trench foundation with gravel-filled poly bags was used, and the mesh bags or ‘hyperadobe’ were used in the majority of the wall. We used individual bags and not continuous bag on this project. These bags are similar to onion bags and they allow the fill to squish out of the tiny holes so that the clay of one bag sticks to the others around it with considerable strength. The hyperadobe technique eliminates the need for using barb wire, and instead we added borax-soaked bamboo stakes in every bag for earthquake insurance.

PAHS design involves the addition of sloping underground sheets of plastic diverting all water away from the base of the building, which keeps the soil around and under the building dry. Because it is dry we can store the excess summertime heat in the soil to be released in winter. Two air tubes wind underneath the berm that is built around the house. The air is moved by convection and the tubes bring in cool fresh air in the summer and warm fresh air in the winter.”

PAHS Principles Explained
PAHS Earthbag House


Comments

PAHS Earthbag House Near Completion — 20 Comments

  1. Im interested about the permitting process for this structure. I live in western Washington as well and with all the research I’m doing it sounds like building an earth bag structure in any county here would be pretty difficult. Did they bypass the process altogether? What county is this located in?

  2. Thanks for your advice Owen. I live in Northern Europe. Could the work carry on during rainy weather or the winter? I’m sure it would be advisable when building to use tarps to cover the walls when it rains. Would this have to cover all the wall or just the top of the wall? Are regular earthbags better for building in an unpredictable climate?

    Would you advise that the walls have to settle a little or cure before adding either the bond beam and/or the roof to prevent the walls from bowing or the bags from slipping?

    I suppose with the addition of temporary formwork to prevent bowing or slippage I may then, perhaps, be better to simply use the rammed earth technique between formers rather than bags. Although my soil has perhaps too much clay for ramming straight, but hopefully this less of a problem in mesh bags, if I understand correctly…

    Because of instability problems with taller walls perhaps it’s better to use bags for the groundfloor and then strawbales for the second half storey.Hmmmmm…

    • I suggest building post and beam in climates such as yours. Build the frame and roof so you can work out of the rain and snow. You don’t want the moisture in the earthbags to freeze and expand, so do the earthbags up to windowsill height during warmer weather. Do straw bales above that for maximum insulation. Make sure the bales never get wet. This is called hybrid construction.

      Properly tamped earthbags do not settle. They’re essentially rammed earth in bags.

      Properly built walls won’t bow. Make sure they remain plumb and level throughout the process.

      Make sample earthbags and see how strong they are after drying. Add extra sand if you have too much clay. Search for Patti Stouter’s soil testing guide at EarthbagBuilding.com for details.

  3. Owen, do you think it’s possible to single-handedly use continuous mesh bags or better to use individual bags? I’m going to be doing much of the work myself.

    Also, what length of rebar would you suggest you need to reinforce the straight walls? |And at what interval?

    I’m looking to build straight walls that are 6m long and 4m high, a 1.5 storey extension, with a ground floor ceiling at 2.5m high.

    • You’ll probably have to use bags. I don’t know of any way one person can fill tubes without building a loading device. I’ve seen a couple of these devices (photo of one in my ebook) and they look cumbersome to use and time consuming to build.

      Ideally you can find a way to speed up moving the material up on the wall. That will be the slowest, hardest part.

      Rebar: You can do internal or external pinning. On tall walls I would do external pinning. Add the pins about every 2′-3′ both sides (opposite each other) when you reach half height. Remember to lay lengths of baling twine between every few courses as you go. Add the remainder of pins when you reach the top of the wall. It’s good to have these extend down past the other pins (overlap) about 2′ for added strength. Search this blog for keywords ‘external pinning’.

      Tall walls are someone tricky. Make sure everything remains plumb. Add some temporary braces here and there to prevent bowing or slippage. And don’t forget the bond beam.

  4. Hello,

    I see you talk about the green mesh bag or roll. You mention that they are better to use in one of your YouTube video …any web-site were we could purchase them. If any one knows, I could be reach lroberte@yahoo.com

    Thanks

    Marie

  5. Any idea how the bond beam for the roof was formed? Don’t think it was poured as it’s circular and would involve a lot of framing. Stiff mix, hand molded?

    • You’ll have to ask Scott Howard to find out what they did.

      While a bit tricky and rather time consuming, you can form curved bond beams with 1/4″ plywood. That’s what we did on our earthbag roundhouse. To do this you’ll need ‘spreaders’ — something like 1/4″ rebar to keep the sides spread apart, and wire to prevent the forms from spreading too much.

  6. I like the idea of the air tubes beneath the berm. Do you have diagram of this?
    Our earthbag home in Patagonia is proving that the PAHS system works and it is very simple. As we enter fall of the second year in our home, we notice that the temperature is between 8 – 10 degrees Celsius warmer than it is outside. In summer it is at least 8 – 10 degrees Celsius temperatures cooler than outside.

    We live in one of the wettest places in Patagonia and the world for that matter. So removing moisture has been the biggest issue with our earthbag home. The PAHS system does just that. We put sloping plastic at least three and often to five meters around the home over a base of expanded polistyrine.
    Now our Chilean friends enter our home in winter and the first they say is ‘Calientito’ meaning warm, even when we have no fire. And they love having warm feet. which is not what you get in the other regular wooden Patagonian homes, always freezing feet is the truth.

    We have built a sunroom at the back of the house to further heat up the home.
    As well we have built a green house using the Pahs concept and earthbags and this is producing the most amazing vegetables, that have not been grown around here… the warmth beneath and in the earthbags is enabling us to retain heat longer.

    We are building a guest cabin and this one will also be PAHS style and that is why I am interested in your air tubes.

    All the best to you.

    • Thanks for the report, Paul. Demonstrating viable alternatives — living by doing — is very effective in bringing about positive change as you well know. People are slow to change, but when they see practical solutions they eventually come around.

      A previous blog post explains some of the details: PAHS Principles Explained http://earthbagbuilding.wordpress.com/2012/02/14/pahs-principles-explained/

      There are pics on the Internet showing the earth tubes being installed. You can also buy his books for complete info.

      But some natural builders have reported mold problems with earth tubes in rainy climates. I wouldn’t risk it, but maybe you can find a workaround.

    • Yes, that’s right. But I’m sure it’s far easier driving rebar through the bags. You can easily pound rebar through many courses. This is one of the easiest ways to reinforce weak areas.

    • We have blog posts on virtually every topic, including this. Try the built-in search engine above. One company in particular has been highlighted because Patti tested samples of mesh from different suppliers. The key words are “discount mesh” because they also have the best price.

  7. Owen….this is the energy design class I have been thinking about for our upcoming build in Northern AZ. I am wondering about how this system would function in a warmer more arid climate with a largely sand substrate.

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