The most common size bag for earthbag (sand bag) building measures about 18”x30” measured when empty. This is often called a 50 pound bag, since these bags are used to store 50 lb. of grain and feed. When filled, this size creates walls about 15”-16” wide. This is a good size for earthbag building because they create stable walls with sufficient mass, and yet they’re not too heavy to handle. Even though earthbags are typically filled on the wall to reduce labor, there’s still a fair amount of sliding and aligning involved. Using bags larger than 18”x30” will require a lot more effort to construct your home. Even a small difference in size adds up. For example, I decided not to use some bags that measured about 19”x30” because I realized these bags would be more difficult to work with but not provide any appreciable added value.

There’s a larger size called 100 lb. bags that measure about 22”x36” measured when empty. Using larger bags will greatly slow construction, although they are very useful for specialized applications such as basement walls, rootcellars and earth sheltering. Larger bags are also more expensive and take extra fill material – more material than necessary for typical above-grade walls. Each additional cubic foot of fill material has to be shoveled, moved, put in bags and tamped. The larger size will work, but they’re much more difficult to build with since they’re much heavier. Plus, they take up additional space.


Comments

What Size Bag is Best? — 14 Comments

    • I would use the standard 18″x30″ bags or tubes. Retaining walls resist the forces of the soil and narrow bags would tend to rotate or tip over. Search our blog for retaining walls. A little more info is in my book.

  1. Hi. I’m kind of new to all this. I’ve been researching building methods for about 3 years now. I’m living in a trailer at the moment and I hate it. But it was the only way to get on my land so I could start saving and preparing to build a better home. (These things just fall apart around you.)

    Any way I’m planing a fairly large home with room to grow a family and plenty of storage. The design I keep coming back too is a pit type underground home with a glass pyramid over a central court yard. I live in the Adirondack Mtns. so snow is an issue. I plan to have a year round garden under the glass.

    So hear is my Question. If I build walls 100′ long and 10′ high out of earth bags and then back fill (allowing for proper waterproofing) Will I need to curve the walls for structure or can I leave them Strait?

    • Long, straight earthbag walls need reinforcing or they’ll tip over. I don’t show this level of detail on my house plans that are on my blogs. I add the reinforcing details after consulting with clients and the engineer. Reinforcing options include post and beam, confined earthbags, adding curves or buttresses, reinforced earthbags as recommended by Precision Structural Engineering, etc. Search these terms in our earthbag blog search engine for more info.

  2. Hi Owen,

    When can we expect your BOOK?
    I thought I read somewhere that you were almost finished a book on earthbag building…?
    thanks again for all the info.
    cheers,
    Laura
    (in Grenada)

    • I’m finishing up the final edits. It’s 99.9% finished, promise! I want it to be as good as possible and I keep thinking of ways to improve it. A companion video will be available about the same time.

  3. So a larger bag should be used when earth sheltering?
    What about when using a very large earth berm?
    Is 22″x36″ large enough?

    The house I am building this summer is going to have an earth berm roughly 75% of its height and wrapping around about 60% of its circumference. I as strongly considering going for a full earth sheltered dome. Although I have read some positive things, I am still slightly concerned about an earth-bag dome’s ability to shoulder the loads involved in earth sheltering.

    Are there any other special considerations to take into account when using earth-bags in conjunction with earth sheltering?

    Thanks.

    • In general, yes, larger earthbags are recommended where earth sheltering is against a wall. This would give you a stronger wall to resist greater pressure.

      Every case is different and has to be examined separately. Some details to consider include curved versus straight walls, height of earth sheltering, length of walls, distance between buttresses, etc.

      Domes are incredibly strong and so larger bags may not be necessary. My dome has about 25 truckloads bermed against three sides and there’s no sign of slippage. Standard 18″x30″ bags were used: http://earthbagbuilding.wordpress.com/2009/07/15/low-cost-multipurpose-minibuilding-made-with-earthbags/

      But this is a small dome. Larger domes with more earth sheltering will need larger bags at some point.
      Be sure to keep moisture away from walls using proper grading (sloped to drain water away from the building), layers of 6 mil poly, swales.

      • Would it be as good to use a double wall of smaller bags versus a wall of big bags for a wall with significant earth berming? I am thinking of the ease of handling smaller bags when working with minimal assistance as a reason for this choice.

        • It depends on the size. Smaller, lighter bags would be more likely to shift and so not as stable. We suggest filling the bags in place and tilting into position so you don’t have to move them. The heaviest thing you have to move is one container of soil at a time (bucket, can or shovelful).

  4. Thanks! These posts are all very helpful to us as we get ready to build our earthbag home and you guys are always so good at responding quickly to questions. We really appreciate what your doing.

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