There’s obviously a great deal of concern about the recent earthquake in Haiti. Disasters like this are all too common, and so we’re working hard to develop at least two low cost, easy to build earthquake-resistant earthbag house designs.

We hope to be better prepared in the future with plans ‘ready to go.’ But in the meantime, we are making good progress. Kelly Hart and I have roughed out some basic design details. Adobe engineer Bill Druc has offered to help with the calculations and designer Patti Stouter has offered to do some drawings. Also, numerous organizations have expressed interest in raising donations, sending building materials and trainers, and constructing houses in Haiti. For the latest news, see Comments at Responding to Catastrophe.

Earthbag buildings tend to flex and distort during an earthquake rather than suddenly collapse as wood framed, adobe, brick and concrete block structures do. Barbed wire and plaster mesh hold the bags together in case of collapse, thus greatly reducing risk of people getting crushed.

Key building details for earthquake-resistant earthbag houses in Haiti:
– Use compact shapes for greater seismic resistance: round, curved, hexagonal, octagonal shapes or domes when culturally appropriate.
– Avoid long unsupported walls.
– Foundation: gravel-filled earthbag foundation (double-bagged for strength) on rubble trench. Best to have at least two continuous courses of earthbags below door threshold.
– Barbed wire: two strands of 4-point barbed wire between courses
– Limit the size and number of doors and windows: these may be available from collapsed buildings or acquired locally to save shipping space. No glass in windows, only shutters that can be locked. Concrete breeze block or screened openings can reduce number of windows required.
– Steel-reinforced concrete bond beam: 6” high x 16” wide
– Truss anchors in the bond beam: embed L shaped rebar anchors or truss anchors at 24″ on center and weld or bolt to rafters/trusses
– Lightweight roof: about 3:12 pitch, metal roofing for roofwater catchment
– Plaster mesh: poly fishnet is the lowest cost, won’t rust and can easily be stuffed into barrels full of building materials. (Barrels are later used for roofwater collection.) Add fishnet to both sides of earthbag walls and connect with poly twine.
– Plaster: cement or lime plaster on exterior; earth plaster on interior

Virtually no structure can withstand a direct hit from a major earthquake, but by combining the building details listed above there is a very good chance the structure will hold together even if the walls should topple. While not perfect, this strategy could save countless lives over the current building methods used in Haiti.


Comments

Earthquake-resistant Earthbag Building Details — 15 Comments

  1. i am thinking about an earthbag house for an earthquake prone area. which method would be superior, the reinforced meshed corners or the Confined masonry construction with earthbags? cost differences? i am thinking about a slightly pitched flat double roof to vent heat. the house would be in central america so radiant barriers are a concern.

    • How big is the house? Small emergency shelters could be built without columns.

      What about your local codes? What do they require?

      What is the seismic zone? You could use both columns and plastic mesh on the corners in high seismic areas.

      Be sure to read everything at EarthbagStructures.com. After that, you can email me and we can discuss the details.

    • have you build your earthbag home and where
      I live in Panama, have the okay to build with earhbags
      wanted to know how you solved the issue

  2. I AM BUILDING A SCALE MODEL OF AN EARTHQUAKE SAFE HOUSE FOR A SCIENCE PROJECT NO WERE I CAN FIND SOME INFROMATION AND BLUEPRINTS TO MAKE ONE THANK U.

    • This is outstanding. Thanks for the heads up. I plan to use this in an upcoming blog post. Thank you, thank you.

      One detail not shown: slightly taper one course of bags just below the metal roofing so water will drain freely.

  3. thanks. any info suggestestions from anyone out there would be helpful. i wanted to make all walls both exterior and interior of earthbag, but I do have to watch my square footage, so I am considering using the cement hollow blocks for the interior to save space (they are obviously smaller). My headache for months has been the plaster choice for the hybrid interior wall as I described in my previous post.

  4. a question about plastering. what do you recommend you use for plastering (interior) if part of the interior walls are cement hollow block. what would you plaster with where the cement block wall come in contact to the earthbag wall?

    • Earth plaster is almost always my preference for interiors. It’s very beautiful (any color you want), easy to work with, safe, low cost, etc.

      Maybe you could add plaster mesh over the block and use earth plaster on everything? Not sure on this. Check into this more.

  5. I suppose at present keep law and order is an issue which just makes this worse.

    I have come across Earthbag building twice in one night. Must read up a little more on the subject.

    Previously I heard of part prefab buildings being used in earthquake areas like Pakistan a few years back.

  6. Steel and reinforced concrete structures are also very strong, but these materials are not affordable in Haiti and other developing countries. (Not to mention that they are not sustainable.) What happens in most cases is a percentage of the cement and steel reinforcing are stolen, and so the structures are not as strong as originally designed. Preventing theft of high value materials from job sites is almost impossible when a bag of cement, for example, may equal one or two weeks local wages.

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