Natural Building Blog

Earthbag Building & Other Natural Building Methods

Interior Walls

Using earthbags for interior walls would take up too much space and so they’re generally not recommended for this purpose. Thinner interior walls are more efficient. The easiest solution is to frame interior walls with 2x4s or, for plumbing walls, 2x6s.

But there are more sustainable alternatives. On some of my plans I use adobe, CEBs, recycled brick or stone around wood stoves for thermal mass. (These materials retain the heat and gradually radiant it back into the house.)

You could also do slipform straw clay (also called light straw clay). I like this method because it avoids sheetrock and the associated taping and texturing, and enables the use of earthen plaster throughout the home. The basic process involves building a recycled or sustainably harvested wood-framed wall 24″ on center, drilling holes and adding saplings through the center of studs, screwing 24″ wide strips of plywood to each side, then stuffing with light straw clay (straw covered with a thin coating of clay slip). Do one course at a time and then move forms up the wall after it has set up. Plaster the walls after drying. This method creates soundproofing between rooms and doesn’t offgass toxic fumes like manmade materials.

Tie interior walls into exterior earthbag walls for strength and rigidity. There are numerous attachment methods, including burying wood blocking in earthbag walls, and using sheet metal anchors.

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12 Responses to “Interior Walls”

  1. Sara says:

    Thanks so much Owen!!

    Also! Pls head into flooring soon!! I wanted to do something with plank (not sure what kind yet) wood floors 8 inches wide with random flag stones put at the entrance ways & in front of the fireplaces & maybe center medalions in some of the rooms…. : )

  2. Sara says:

    hmmm…so, if I frame the walls in sheets of wood, can I plaster or light concrete over them? I guess I can cut holes in the wood to let in light for the square glass ppl use for bathrooms sometimes (I found 20 of them at salvage) and chunks of aqua colored glass…also want to embed stones in arched hallway entrances to kitchen & family room as well as around the 2 fire places….as well as some pebble mosaics around the rooms….

  3. Sara says:

    hmmmm….so, if I frame it with wood sheets, would it be good enough for plastering? or light concrete so I can embed pebble mosaics?? I had wanted to use glass also as in the glass squares sometimes used for privacy in bathrooms (I actually got 20 of them from salvage yard)and glass chunks I found in aqua …. I guess I could cut out the holes in the wood sheets…. I wanted to embed stones around the fireplaces and the arched entries at the kitchen & family rooms….

    • Owen Geiger says:

      Okay, for that I would build standard 2×4 interior frame walls like this: http://www.buildmyowncabin.com/framing/interior-wall-framing.jpg

      Run your plumbing and electric, and get your inspections. Then cover with plywood or recycled wood and apply mosaics, glass, etc. Cover with tar paper and mesh if you want to plaster it.

      Update: People often underestimate how much standard carpentry is needed in alternative homes. I always suggest getting a carpentry book from the library. Get one with lots of basic drawings and photos. Skip over the advanced stuff. You only need to know the basics. Hire a carpenter’s helper if necessary to speed the progress. They’ll have the necessary tools and probably end up saving you money and mistakes.

  4. Sara says:

    So, if choosing plaster over hypertufa interior walls, would u suggest the rebar & mesh centers as well?? I really had wanted thinner earthbags for the interior walls along with rebar poles inserted to keep it strengthened…..timewise,costwise,longterm wear & tear,which would u choose??(remember, I ordered yr 4 plex & converted it to a single home)

    • Owen Geiger says:

      Oh hi Sara. I didn’t realize that was you. Your custom plan had the wide earthbag walls between units removed to save space. The final result is much more practical for use as a single home.

      The easiest option is to frame the walls with wood. I recommend recycled wood or sustainably harvested wood from a local mill. That makes it easy to install plumbing and electric. The rebar/mesh/hypertufa idea would bog you down in weeks of tedious work, whereas the same walls could be framed in 1-2 days by two average carpenters. Also consider covering the walls in recycled wood instead of sheetrock. Does that answer your question?

  5. Sara says:

    Owen!

    Do u suppose hypertufa walls 4-5 inches thick may be a good interior wall material??? I am looking for interior walls that ca n hold up rocks & glass work embedded into it….

    • Owen Geiger says:

      Hypertufa is good for planters, but it probably lacks tensile strength for walls. You’d want to add some type of support such as rebar or remesh. That way it won’t crack or break over the years as doors open and close, etc. So make a rigid rebar grid down the enter of the wall that’s firmly anchored to the floor, adjoining walls and ceiling (trusses). Cover with remesh and then apply hypertufa to both sides. Make sure door and window openings are particularly strong because that’s where the greatest stresses will occur.

  6. Jay says:

    Owen’s original blog post is right on target.

    There are a couple of other ways to think about interior walls, though.

    It CAN make sense to use earthbags for interior walls if that wall will also be serving as a needed buttress for an exterior wall. Clearly, this will not always be the case, but it can be sometimes.

    Also… many people simply avoid building interior walls as much as possible. That concept can be extremely effective.

    Instead of building more walls, consider an open concept design. Don’t build more walls than you REALLY need.

    Strategically place furniture in such a way as to divide a space as you want. For example, if a wall is going to have a bookcase or entertainment center up against it anyway, why build the wall at all? Just use the bookcase or entertainment center as the wall, and use an attractive decorative treatment on the backside of the bookcase. This works best if the bookcase can be anchored either to the floor, to a side wall, or even to ceiling/roof joists to prevent accidentally tipping it over.

    Curtains and Shoji screens can also be very effective. The beauty of those is that they can be moved or removed to fit a particular situation.

    My point is… don’t allow “conventional expectations” of standard construction to force you into design decisions that you may not really need or want.

    There are times when interior walls are the best solution, and when that is the case, it would be wise to follow Owen’s suggestions for building them. Just make sure you need the wall before you build it.

  7. Melanie says:

    Thanks so much for your response. We stumbled across this floorplan on Pinterest and knew we’d found the one. We’d always planned on following your advice to build in a modular fashion, and it seems like this plan would lend itself very well to that. We hope to build the two middle sections first, then finish the outer two hallways and rooms after we move in. We hope that eventually, we can finish the circle by building a low wall around the back of the house to create a kind of courtyard with a garden in the middle. We are pretty sure we understand how you built the roof on your roundhouse in Thailand and were going to do something like that on ours, but we aren’t really sure how to handle attaching the roundhouse roofs to the roofs over the hallways in between. We’re still figuring that part out. Anyway, I would be interested to see your visual interpretation of a plan like this. It reminds me of your Three Roundhouses design. Feel free to use it as inspiration. We sure did!

  8. Melanie says:

    Hi, Owen. My husband and I are committed to building an earthbag home in a few years (once we locate and purchase the perfect piece of land) consisting of several roundhouses attached by curved hallways similar to this plan: http://media-cache-ak0.pinimg.com/originals/9d/4a/53/9d4a53a3e69e9f77b00fa614fa85b2f8.jpg

    During our research, we saw an interesting method of building interior walls using empty aluminum soda or beer cans as “bricks” that were stacked and mortared with earthen plaster. I really like the idea of using cans for this purpose, but I am not sure how practical this type of wall would be. We will be building in south Louisiana, which has a subtropical hot, humid climate with lots of rainfall, and while it seems like these lightweight, relatively thin walls might be a good way to cut down on interior thermal mass, I’m not sure if they would be sturdy enough or how well we could incorporate electrical or plumbing into them. I suppose we could funnel sand into the cans to make them heftier, but I have no idea if that would be necessary or not. Do you have any feedback, resources, or advice to recommend regarding this method of building interior walls?

    • Owen Geiger says:

      That’s an excellent floorplan. Thanks for sharing. It’s very well thought out, very livable.

      Aluminum cans are best recycled. Locking them up inside a wall doesn’t make sense. Use something like recycled wood, possibly with straw/clay

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