Passive Annual Heat Storage (PAHS) earthbag house by Earthen Hand Natural Building. (click to enlarge)

Passive Annual Heat Storage (PAHS) earthbag house by Earthen Hand Natural Building. (click to enlarge)


PAHS design principles can help heat and cool the house. (click to enlarge)

PAHS design principles can help heat and cool the house. (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, perhaps a first for hyperadobe. 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.

Construction continues on the finish work. Earthen Hand will host more workshops onsite there during the summer of 2012. Please see www.EarthenHand.com for workshop information.

More PAHS info at Earth Shelters.com


Comments

PAHS Earthbag House — 12 Comments

  1. Thank you Owen for your quick reply. Would like to send you the plans, which email is best to communicate with you. There’s no way to attach the drawings to this reply.

    Best,

    John Abbate

      • Dear Owen, Thank you and we just sent you an email with plans and elevations to your Strawhouses email address. Please not I made an error in my information. We are in a medium earthquake zone. We misread the map. Sorry for any confusion. Thank you, John

        • Thanks. I just wrote you back. This looks like an excellent project. Good job. I look forward to hearing how this goes. Please document everything and share with others.

  2. Dear Owen,
    John Stevens has contacted you about a project in the Philippines we are working on. I am one of the designers on the project. We are planning to build mostly 2 story units and would like to ask you some advice on the project. We are currently drawing up the plans and would be happy to share them with you. Our main concern is building such high walls in a typhoon & earthquake zone. Most of the structures will have traditional thatched roofs but we would like to build some 2 story flat roof houses to that would require a tiled well sealed roof that would be heavy needing even more support. We thought to add buttresses and steel I-beam or solid hard wood, column and beam frame work to the structures to support the high walls and heavy roof. Please let us now if we can ask you advice on this? Thank you and let me say the work you are doing & the way you share it is very motivational for those trying to build eco-projects on small budgets! John Abbate

    • You can send me the plans and I’ll take a quick look. In general, you can go 2-story, but I would only go one story in the Philippines due to the risks you’ve mentioned.

  3. Owen,

    What length rebar would you use to reinforce the earthbags and at what spacing? Would this be the same when using individual bags and continuous mesh bags?

    • You may not need rebar in the earthbag walls. Rebar is primarily used where you want extra reinforcing to resist hurricanes, earthquakes, etc. The spacing depends on the design and loads. We used it on our roundhouse because we had lots of large windows with just short walls between. Some people add rebar next to doors and windows since these are the weakest areas. So I think of rebar as just one technique in a bag of tricks. Use as necessary. For instance, maybe a doorway feels a little unstable as the wall gets higher. Add rebar on each side of the door at half height, another piece when you reach the top. The top piece extends past the first piece about 2 feet.

  4. What is meant by “adding” bamboo stakes? Are they driven down vertically through the bags? How many layers, if so?

    • You don’t want to skimp on reinforcement in earthquake zones. I would use barbed wire, rebar pins, buttressing, reinforced concrete bond beam and mesh on both sides of the walls tied together. 8′ high walls and lightweight roof preferred. Don’t add too many windows and doors. Build small, simple shapes like domes, roundhouses, or square or compact rectangular houses.

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