From time to time we answer reader’s questions.
Paul: In the EcoOcha video I noticed they tamped the sides to reduce the ‘log cabin’ look and to reduce the amount of plaster required. This smoother surface would be much easier to plaster.

Owen: Yes, more and more builders are flattening the walls like this to save plaster work. It’s strange, but for some reason some people say this doesn’t work, that the bags will crumble if you tamp the sides. Maybe their soil has insufficient clay. I don’t know, but it works great for us and for others.

One thing is for sure — if you don’t at least try to flatten the walls somewhat then you’ll have to apply a massive amount of plaster to even out the walls. That would take a great deal of time, effort and materials.


Comments

Flattening Walls to Reduce Plaster Work — 8 Comments

  1. I’m planning on building the Beachcomer when I move to Belize(if they allow it naturally).
    I would like to know if you think that by using the “Drivit” method of finishing the outside, would it still be Hurricane resistant.
    By using 3″ styrofoam, I feel that this would provide ample insulation and you can use it to make very nice architectural designs with it also(different thickness of styrofoam).
    Thank you for your time
    Jeff

    • Save your money. Insulation isn’t needed in the tropics if you use wide roof overhangs, lots of ventilation, high sloped ceilings, roof vents, etc. Tamp the outside surface of bag walls to create flatter, more uniform surfaces, and save materials and labor.

    • Tamp as low as you can and the backfill will cover the remainder. This raises the point to 1. raise the building site to prevent moisture problems, 2. add some backfill around the sides (about 6″ to12″) to direct water away from the building.

  2. Hello. Very, very new here (just found the concept and site about an hour ago) so go easy if this is an abysmally stupid suggestion. Is my impression that earthbags are normally tamped “free form”, meaning supported on bottom only, correct? And then some builders tamp the exposed sides “square” after stacking? Would it help to place the bags in a 5-sided (including bottom) form, then tamping, then stacking the “bricks”? Or would the loss of formed shape when stacking render this useless? Otherwise the cost of the exercise would seem to be confined to scrap lumber for the forms and some extra handling.

    -Alex

  3. As I see it, the side tamping would be a timing issue. With the materials in the bag still damp, it would be easier to tamp and hold it’s shape, especially if this were to be done on the level below the top row of bags, so that the weight of the upper level would help keep the lower level in shape. Perhaps a slight dampening down before side tamping would work best.

    Tamping the sides of the top level could also be done, perhaps with a light tamping of the top surface after the sides were tamped, to shape the bag/tube into a more rectangular cross section.

    This would be an individual choice, of course, as some people prefer a more organic, rounded look to their wall structure.

    • It helps to have several courses in place before tamping the sides. That way you can easily see where the high spots are. Walls are always slightly irregular even if you’re careful, so you want to flatten these obvious bulges.

      We didn’t have much success at moistening and softening the sides once they started drying. It’s difficult or impossible to get water to soak in versus running down the wall. So don’t wait too long.

      It’s a matter of preference, but we didn’t flatten the wall entirely. It seems like a good idea to leave the recesses between courses to give the plaster something to grab onto.

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