It’s difficult to know for sure how long earthbags will hold up in sunlight. Some brands fall apart pretty fast, as soon as a few weeks. Equatorial and high elevation areas may experience slightly more rapid deterioration due to increased UV levels. From my experience and what I have heard and read most bags hold up okay for about 2-3 months. The safest way is to buy tarps or black poly and keep them covered as much as possible.

However, tarps are prone to blowing around in the wind and can be a bit of a nuisance. If you’re doing a large job, then you can either buy UV resistant bags, which cost more, or in the case of vertical walls do one wall section at a time (including adjacent corners) and apply at least one coat of plaster as soon as possible.

Note from Kelly: One good indicator of how long the polypropylene material will last if exposed to the sun are the tarps themselves, which are often the same material. My experience is that they just get progressively weaker as time goes by, and may show signs of deterioration after about two months’ exposure and usually by about 8 to 10 months it is pretty easy to punch holes in them with a finger. And these tarps are often supposedly UV resistant. Obviously the best thing is to not take chances and keep the bags covered at all times, except when working on them.


Comments

How Long Will Earthbags Hold Up in Sunlight? — 9 Comments

  1. Hey, I was at the dump shop recently and there were four sexy looking rolls of blue plastic tubing of the kind i think used for roofing insulation. They werent that wide bags, but might be handy for small landscaping efforts… they are not woven poly bags of the kind I am working with for the dome project, but they looked mighty useful and they are cheap. Is the surface going to be too slippery for that, without the woven exterior? is there any other reason, such as breathability, that would prevent me from using those bags ? could i use them to finish off the top of the dome?
    Jill

    • As far as slipperiness goes you can always use some mesh to hold the plaster in place, but I would be concerned about your fill material not being able to dry out or cure if it is a dampened mix.

  2. Not quite related to this article specifically, but no where else to put it. Do plastic earthbag bags off-gas fumes like VOCs, etc.?

    • I don’t really know. There’s no discernible smell, and I’ve never read or heard anyone warn of this. A quick search on Google didn’t turn up anything. It’s best to avoid all synthetic materials as much as possible, although in this case most people seem to agree the benefits of earthbags far outweigh any negatives. And keep in mind, the bags make up just a tiny percentage of the over all structure. And even then, they’re buried behind thick plaster.

      Maybe one of our readers could look into this more thoroughly and send us their findings.

    • Superadobe bags, like most sandbags (earthbags), are made of Polypropylene.

      If you google for Polypropylene MSDS (material safety data sheet) you’ll see that only concerns for safety come from burning polypropylene in unventilated spaces (and coming in contact with hot, melted , burning plastic).

      It is a very safe material, its used for everything from water bottles, pill bottles, candy containers, yogurt containers, plates/forks/spoons, blankets, shirts …
      thermal underwear

      100% Polypropylene is not reccomended for clothing/bedding if there realistic risk of explosions (refineries, war-zones) because it can easily melt onto your skin (imagine that, a bomb goes off nearby, you’re uninjured from the blast and shrapnel, but your underwear has melted into your skin) which requires surgery to remove, and carries a high risk of infection (the part that can kill you).

      Ok, back to http://en.wikipedia.org/wiki/Polypropylene#Degradation

      Polypropylene, when exposed to UV breaks down into
      http://en.wikipedia.org/wiki/Aldehydes
      http://en.wikipedia.org/wiki/Carboxylic_acids

      So if you were to build your earthbag house in a hermetically sealed sun room (airtight), and if you were to leave your polypropylene walls exposed to sunlight to the point that they fall apart (say 1-3months for non-UV-resistant polypropylene). And all the polypropalyne has all dissolved, and then you walked in there and tried to breathe in all the vapors, there is no chance it would do you any permanent harm. Ok, you might be disturbed by the smell and fall and hit your head, or you might get an astma attack, but if you leave the door open for 5min you’ll be fine.

      To simulate what this unlikely scenario might be,
      8 fl oz of acetone nail polish remover
      get a shallow pan/tub/bowl and pour,
      place pan in middle of room,
      wait till noon and then pour acetone,
      leave room.
      Come back hour (or two) later and acetone will be airborne.
      open door and walk in then say “fooey that stinks”,
      then open a window and let it air out.
      Be careful in your room selection, acetone is a solvent, it might ruin the finish on your plastic items, or peel some stickers…

      in conclusion, practically everything will outgas (http://en.wikipedia.org/wiki/Outgass)
      but you’re safe if you open door/window daily (like when leaving/entering). Polypropylene is very safe.

  3. what is the life of the earthbag construction?
    What is the durability of earthbag home in 2 types of areas below
    – Snow fall hilly area
    – rainy area.
    Regards
    Faisal
    Pakistan

    • More testing needs to be done to confirm the longevity of earthbag building, but so far anecdotal evidence indicates it is very durable. A properly designed building should last 100 years or longer. Earthbag building is fire and rot resistant, very strong, etc. It is suitable for both cold regions (with use of insulating fill material) — research Insulated Earthbag Houses: http://www.earthbagbuilding.com/articles/insulated.htm. Earthbag building is also well suited to hot climates, rainy climates and disaster prone areas.

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