New Mexico Dirtbags

Earthbags 

For those that don't know what earthbag construction is, this page is just a brief  introduction.  For those interested, we provide links to more information. There are also plenty of books & websites out there that go deeper into the subject than we do. 

Start with the basics. Take some clay-rich dirt in your hand. Moisten it, squeeze it, roll it into a snake. Now add a little sand, squish it into a form, lay it in the sun & let it bake for a few days. It gets hard. Congratulations... you've just made adobe. (Real adobe will have some straw, manure or fibrous material to help bind it together.)

If you put this wet clay/sand mix in a sandbag & stack the bags, pound them flat, smoosh them around to your liking (straight lines, curves, rounded corners, whatever) and let them dry, then you have earthbags - modular building blocks, adobe bricks in a bag.

Alternatively, filling your bags with dry scoria (lava rock) avoids the need for mixing soils or adding water. Additional advantages are the bags are lighter in weight, the voids in the scoria provide insulation, and you can buy them from us pre-filled.

With the right fill & a little finesse, earthbags can achieve a strength & stability superior to concrete blocks. They're low-cost, low-tech, have a relatively low carbon footprint, and - depending on your fill material - are free of the chemicals & outgassing that are increasingly common with many modern building materials. 

History:

The idea of using dirtbags/earthbags isn't new; think of the sandbag trenches &WWI sentry fortifications from World War I. There are suggestions that they were used back in the Revolutionary War. The Industrial Revolution allowed mass production of textiles; before that, baskets filled with dirt & rocks (the predecessors to gabions) were used for fortifications as far back as Mesopotamian times. But the application of bags with a wet fill that'll set up as an alternative building material is fairly new, starting around the 1960s, and can be largely credited to two individuals.

One was Edward Dicker, who patented the "Stack-Sack" process in the 1960s (burlap sacks filled with a dry mix of sand, cement, and gravel; soaked in water & then stacked, with rebar driven through every couple of feet to anchor them). Further refining the concept was Iranian architect Nader Khalili, humanitarian and founder of the Cal-Earth Institute, who recognized that people left homeless in war zones and disaster areas around the world often have (if little else!) abundant access to three things; sandbags, barbed wire, and dirt.

The beauty of earthbags, especially in contrast to more conventional, rigid and mass-produced material lies in their simplicity, their ease of handling, and their ability to be laid in curves. They're ideal for bordering sinuous walkways, garden beds, terracing, erosion control, building arches, serving as foundations or stem walls for cob or straw-bale constructions, or more ambitious projects. Once they're fully cured & well plastered, no one would know that they're not adobe (or something more conventional).


Advantages:
  • Aesthetic - easily covered with plaster or stucco
  • Versatile, graceful, and easy to work with
  • Fireproof
  • Non-toxic - no fumes or allergens
  • Low-tech, requiring a minimum of tools or experience
  • 12" thick walls provide superb insulation
  • Stable; excellent earthquake resistance
  • Perfect for managing erosion, rain/sediment runoff, and flooding
  • Ideal for low-cost ponding & concrete washouts
  • Tamped dimensions of standard 14"x26" bags at a manageable 30 lbs each = approx. 12" wide by 12" long by 3" high. If you choose, you can pack up to double the amount of fill in the same size bag to achieve a 60 lb. bag with tamped measurements of about 18" x 12" x 4". (Bigger bags mean fewer bags, but they're much harder to maneuver.)
Making your own:

With the basic materials (bags, dirt, barbed wire to lock rows of bags together, and a tamper), anyone can design and build with earthbags. If your dirt doesn't have sufficient clay, you can add it, or stabiize it with lime or cement.

You don't even need to buy bags. Sure, we're happy to sell them to you. But some people have had success using alternatives like thrift-store pillowcases, sheets sewn together, etc. The point is to have a container or wrap that will hold & confine the wet fill, and that will survive the tamping without splitting a seam. Once the contents of the bag have cured & and your construction is plastered, it doesn't matter at all (structurally speaking) what the bag was made of.

If you're new to this, you'll find information, links, and resources on these pages & elsewhere to help you get started.

Empty bags:

Our standard sizes are 14"x26" (approx. 36 cm x 66 cm). We also carry 18"x30" bags. These are treated with 1,600 hours of UV inhibitors & have tie strings.
  • Polypropylene bags (standard size) are $0.50 each, $40 for a hundred, or $300 for a thousand. They're available in any quantity desired. Shipping and applicable tax may apply. Click HERE to see our prices on poly bags.
We can also get tubular bags on a roll in a variety of widths & lengths. These are special-order and require advance payment.
  • Burlap bags (new, additive-free, 9 oz. weave, 14"x26"), start at $1.25 each. Again, shipping & tax may apply. See our store page for current prices.
Bags in either material are available (by special order) in a variety of other sizes, up to 3 feet long and beyond - though they may not have UV treatment. Expect about a week for us to get them in. Pre-payment or a deposit may be necessary for all large & special orders.
  • Specialty bags include medium weight (in colors, if you like) in 14"x26" or 18"x30". They're heavier & are treated with 2,000 hours of UVI. We also carry heavy-weight black 14"x26" bags that last for four years or more; mesh bags; near-indestructable snake bags (6"x48") and more.
Tools:  

We provide 4-point barbed wire in rolls or by the foot. This is used between the courses of bags to lock them together. We also provide tampers, bag fillers, sifters, zip ties, trowels - pretty much anything you need. See our store here

If you live out in the boonies & want us to find you something to add to your order (whether it's a mantle for your Alladin lamp or chocolate espresso beans from Trader Joes), we'd be happy to look around & give you a quote.


Plastering:


After building, you'll need to cover your structure. Popular materials include lime, cob, adobe mud, papercrete, stucco, and earthen plasters. Typically, you'll want to add one or more rough basecoats, and then a finish coat that will add color, texture, durability, and weatherproofing. Check out our plastering/rendering pages (in progress!).
 



* New Mexico residents, please add NM gross receipts tax of 7.00% to all orders.
All sales are final. Defective merchandise will be cheerfully replaced at our discretion.

505.750.3478 (DIRT)
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USDA's NRCS
Web Soil Survey
mapping engine

to see
what kind of soil
is on your land!


Soil type testing guidelines HERE


Why not to use
concrete (cinder) blocks




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