Energy performance on most buildings can be improved with insulation, including those made of earth such as adobe and earthbag structures. Although most earthen structures are located in hot, dry climates, there is increasing demand for low-cost, eco-friendly earth building techniques in cold climates. This article explores four innovative methods for insulating earthbag buildings, which extends their building range to cold regions.

Most earthbag buildings use polypropylene grain bags or mesh bags filled with soil. Bags or tubes can be used. We demonstrate bags, because they’re often available recycled for very low cost. The bags or tubes are filled in level courses and then tamped solid. There are typically two strands of barbed wire between courses to bond the bags to each other and add tensile strength. The building process for insulated earthbag houses is nearly the same, although the materials would weigh significantly less and speed construction considerably.

Unlike other earth building methods, earthbag building has the unique advantage of providing either thermal mass or insulation, and therefore can be adapted for cold climates with an insulated fill material. Scoria, pumice, perlite, vermiculite or rice hulls are all suitable insulating materials. These materials are natural, lightweight, easy to work with and non-toxic. Most (all but rice hulls) will not burn or rot and do not attract insects or vermin. In addition, all but rice hulls are not adversely affected by moisture and can be used as part of earth-bermed or earth-sheltered structures. Recycled polystyrene (Styrofoam) is another good possibility. Another possibility is adding foam board or foam insulation on the exterior of earthbag walls, as explained in the 4th option.

You can read the entire How to Build an Insulated Earthbag House instructable by Owen Geiger for free.


Comments

Instructable: How to Build an Insulated Earthbag House — 17 Comments

  1. Owen Thank You so much for your help and speedy responses!
    I went searching for scoria,pumice and perlite in my area and all I can find is what they call Lava rock. Would this do for insulating and what size rocks would be recommended (they have Black lava rock 1 inch and smaller mix)
    Also how would I calculate how much I need ? They sell 12 yards for $1500. is this a Good Price? I justy dont know what is considered a good price for rocks???

  2. I live in a Very Cold Climate – 40 in the winter. I wonder if I did earthbag construction, with another layer of earthbag to the outside filled with rice hulls, and in side and out covered with cob or some type of earthen plaster. It will be earth sheltered on the north, east and west sides, Passive solar and rocket stove for heat. Is that going to be sufficient to keep us warm? Also if this is a possible mix of styles what would my options be for supporting an earth sheltered roof?

    • Everything sounds good except: I would use insulation that can’t rot and a larger wood stove. Rocket stoves are fine for small spaces, but a bigger stove is desirable in extremely cold areas. Buy a decent used stove for $100 or so if money is tight.

      You’ll need a very strong roof to support a living roof — logs, etc.

      Maximize the solar aspect. Something along the lines of this earthbag earthship is ideal: http://earthbagbuilding.wordpress.com/2010/11/06/half-moon-earthbag-earthship/

      And what you’re calling cob is actually just earthen plaster. They both use similar materials so it’s a little confusing.

      • Thanks for the Quik Reply Owen! I will definately add in the Stove and as I am figuring out my house I may add a second rocket stove as well as I would love to be able to heat bed platforms and benches.

        For the roof I am hoping to anchor the roof logs into the hill the house will be built into. I am consulting with an engineer as to the feasability of all designs on the house. Lucky for me I have an Engineer in my family.

        And yes I definately want the solar aspect as efficient as possible. we are wanting to be Completely Off Grid. Using solar, wind and in emergency a generator.

  3. I find your articles very helpful. Can I build an earthbag home in the southern hills of Guayama Puerto Rico? What type of soil you recommend I use, the area has a sand and clay. Can I use that? The area has pretty low humidity and dry climate. Please advise.

    • Sure. You can build almost anywhere and use almost any soil. Look for soil with enough clay so you don’t have to mix it. Make some test earthbags and let them dry. They should turn very hard and not crumble apart. Add more clay if they are crumbly.

  4. I love your home and I plan to build one in costa rica. Nights can be as low as 60 and day 80 degrees. Do I need insulation besides the bags? If I want one of your plans a little different can you do that for me?

    • You don’t need insulation due to the thermal flywheel effect of soil. The soil will hold the heat from the day time and release it gradually at night.

      Yes, I offer custom plans. Just email me from the About Us page.

  5. Hi Owen, I love your creations, very nice, easy, cheap and sustainable way of construction. Looks like earthship, both ways seems good.

    Have you ever wonder to fill the bags with rubble? I think it would be better to use rubble instead of earth, because earth is useful for other things that rubble isn’t useful for. It’s more efficient to use rubble in bags and earth for plants. In addition, it’s more ecological because otherwise, rubble is waste.

    Keep up the good work ^^

  6. This information is amazing!!! I have just heard about such a thing and am going to attempt this in the near future!! I have a question… what is considered colder climates? I am debating on insulation or not… I live in so. cali near the beach and just curious how well it would isulate against our rainy winters here. It doesn’t freeze but it can get bitterly cold. Thanks for the reply, I would appreciate it!!!

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