Solar Pit House Building Details

Solar Pit House Section View (click to enlarge)
Solar Pit House Section View (click to enlarge)

Specifications: 1,127 sq. ft. interior living space, 441 sq. ft. interior greenhouse, total = 1,568 sq. ft. interior, Footprint: 36’x53’

As explained in the previous blog post, this modern solar pit house is based on the traditional pit house. The construction is much the same. Additional ‘modules’ have been added to create an elongated rectangular design for added living space and windows added on the south for solar gain. Each module is based on wood posts set in geopolymer or concrete footings. Wood beams approximately 10”-12” diameter are joined at the posts with half lap joints and pinned in place with rebar or logging spikes. Smaller poles around the perimeter lean against the beams. 24” wide earthbag walls with a reinforced geopolymer or concrete bond beam rest on rubble trench foundations.

The entire structure is surrounded by insulation and moisture barriers, both of which can be obtained as recycled materials. The Solar Canadian [their blog is currently unavailable for some reason] reported that farmers use large plastic bags for storing grain for one year and then discard them. They should make a perfect moisture barrier. And, as discussed in a previous blog post, recycled polystyrene is available. In this design, loose polystyrene is used around the perimeter, and home-made rigid board insulation is used on the roof and under the floors. Be sure to test the rigid board insulation so it doesn’t compress and cause cracking in the slab floor.

Other features:
– Sloping, earth-sheltered design has no vertical walls exposed to the harsh wind. This greatly reduces heating cost.
– Radiant floor heating is the recommended heating system. At least one back-up heating system is called for due to the extreme climate – either a wood stove or propane heater.
– A window wall separates the greenhouse from the main living space. Solar powered, heat activated fans blow heat from the greenhouse into the home, and cold air return vents draw cool air back into the greenhouse.
– Double door airlock reduces heat loss.
– The entry or mud room has space for coats, boots, shovels, snowshoes and greenhouse window insulation (possibly more polystyrene panels).
– The entry vault helps block westerly winds and prevent drifting snow from accumulating on the greenhouse roof.
– Pantry provides long-term food storage to reduce trips to the store.
– Storage room for greenhouse supplies and potting bench.
– Buried cisterns (not shown) with gravity flow design or back-up water hand pumps in case of blackouts.
– Joseph Jenkins sawdust composting toilets greatly reduce water use. Water conservation is important since water deliveries are expensive and unreliable in remote areas.
– Enhanced livability over current low income housing: traditional design for cultural acceptance; warmer (huge psychological boost when the floor and air temperature are always comfortable); more pleasant living environment with abundance of plants and much greater daylighting (combats cabin fever); fresh food production and higher oxygen level; superinsulated design with far lower energy costs (money stays in the community); adequate space for extended families and storage; greater self sufficiency.

26 thoughts on “Solar Pit House Building Details”

  1. Spot on with this write-up, I really think this amazing site needs a lot more attention.
    I’ll probably be back again to read through more, thanks for the advice!

    Reply
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  3. That is, the fire was only necessary in extreme cold…earthen house construction and orientation facilitated passive (solar/earthen) temperature adjustment for hot or cold days.

    Reply
  4. In a discussion with a builder from the Sto:lo people, which had pit houses inland off the northwest coast, “radiant floor heating” was accomplished by a 4 layer floor with a central fire pit: packed earth, sand, gravel and packed earth; which was only necessary in extreme cold.

    Reply
  5. Also, how hard is it to make it handicapped accessible? I would need for sure no stairs, wider than standard doorways and larger bathrooms. Any suggestions?

    Reply
  6. I love this design. Do you know how much (at least per sqaure foot) it would cost to build something like this? Do you know when you are going to have this design available?

    Reply
    • That is exactly what I was thinking, Kelly. In fact, I AM going to build this on a hilly portion of my property in Tennessee. I will have the pit area in the front just as you have observed like the $50 underground house with the porch area cut in so the weight of the earth is not pressing into the house.

      I love this design and would welcome any suggestions and would like to purchase more detailed plans of this if available.

      Reply
    • There are a few earthship projects that i know of in the tropics. There was one built in Guatemala last year. Took 2 weeks and about 60 people to build. They are building a second one on the same site in 2013. See the video http://www.youtube.com/watch?v=eU_2yysjkas
      These people as well as Longwayhome would have good insight into how the earthship did after the first year in those conditions.

      Reply
  7. Imagine the psychological boost from spending time in a warm, sun drenched, oxygen rich greenhouse and eating fresh, organic produce daily. And, no doubt, homeowners will love the greatly reduced bills.

    Now we need to attract some financial backing to fund a prototype.

    Reply

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