Lightweight, insulating geopolymer is ideal for many applications.

Lightweight, insulating geopolymer is ideal for many applications.


As reported in a previous blog post just recently, low cost raschel mesh tube material is now available. (Thanks again to Patti Stouter for tracking this down.) Affordable mesh tubing means hyperadobe is now a more realistic option for many earthbaggers. A growing number of people think hyperadobe is the fastest, easiest earthbag method currently available. It all goes back to Fernando Soneghet Pacheco, the original developer of hyperadobe, who improved the superadobe technique because after having done a course he realized that there were a few problems. The hyperadobe is superior because mesh bags or tubes are narrower, so less soil is needed and it’s cheaper. You can also save money with doors and window bucks (rough frames) as they don’t need to be so wide. The soil dries much faster. The mesh material increases stability and in some cases can eliminate the need for barbed wire. In addition, plaster bonds more readily to the mesh.

The real purpose of this blog post is to point out how lightweight fill materials such as scoria and pumice can be used in the hyperadobe system to create superinsulated buildings in harsh climates. Options include loose scoria and pumice with no binder (requires some additional reinforcing), and scoria, pumice, recycled polystyrene, perlite or vermiculite bonded with clay. Although it hasn’t been done yet, I believe stiff mixes of pumicecrete, perlite geopolymer cement, cellular lightweight geopolymer concrete, hempcrete and other similar materials could be used. This idea ties in with my blog posts about Lightweight, Insulating Geopolymer Earthbags. The main addition here is the suggestion of using mesh bags and tubes to improve the system. Please let us know if you experiment with some of these materials.

We’ve already reported on hyperadobe in detail, but here are a few links for new readers:
Hyperadobe Update
Open Weave Fabric: Ideal Working Properties
Hyperadobe Continued
Mesh Bags Versus Poly Bags: Differences in Working Properties
Mesh Bag Details
More Hyperadobe Videos
Hyperadobe Update from Brazil


Comments

Lightweight Hyperadobe — 25 Comments

  1. Hi, I’m in NM and wanting to build with hyperadobe. I’m looking for a supplier, but I’m not entirely sure what to look for. I see you mention Raschel Mesh the most, which I’ve also seen on other forums. But I’ve also seen people mention Leno Mesh, which I can find for really cheap. A random google image search for “Leno mesh vs Raschel mesh” brought up a picture that showed Leno mesh as rated to be stronger than Raschel. So, that makes me wonder if Leno Mesh would be okay?

    Also, I am building a 15′ inside diameter dome. From my research, it seems that my bag size needs to be 18″ – however, I’ve seen one source (CalEarth) say that it should be 18″ when empty, and another source (Curvatecture) say that it should be 18″ when tamped. Do you know which is true?

    This brings me to my third question – I’ve seen you mention that they mesh bags stretch. Does that mean I should get a 15″ bag (for example) if I want it to be 18″ once tamped? Or does that mean it just loses less of the width when being tamped? I guess my question is – if I want 18″ wide bags once tamped, what size bag should I try to find?

    • I think that for a dome that size walls that tamp to about 15″ thick are good. See http://www.naturalbuildingblog.com/mesh-tubing-for-hyperadobe/ for specific information about stretching raschel mesh. As far as Leno mesh, I have no experience, but if it is stronger than the raschel then it should be strong enough. My guess is that it doesn’t stretch nearly as much, so if that is the case then you can start with 18″ flat bags.

      • Hi Kelly,
        I just wanted to update for the record in case anyone else is interested…
        I ordered a sample of the leno mesh bag (found at the link below – a US supplier). It is 18″ wide and 30″ long when empty. It comes with a drawstring to close the top. I filled it as much as I could (pretty close to the top), then I closed it with the drawstring, lowered it flat on the ground and tamped it really hard. It held up beautifully. I then reopened it, crushed up and dumped the earth inside, and filled it again and tamped it again. Even on the second go-through, it held up without tearing. I feel confident I could repeat the whole process yet again and it would still hold. The drawstring was also strong enough to keep the bag closed.

        Once tamped, the final size came to 27″ long x 16″ wide x 4″ high.

        Here is the link to the product: https://www.glacierv.com/SPD/item-no-1089–35-lb-poly-leno-mesh-bag-with-draw-cord–500-pack–8000052A-1409950802.jsp

  2. hey there

    this is Don in Kirkland AZ.

    I’m in the middle of overhauling a water tank/pump house and it was a wooden earth-bank structure and it basically caved in. I am looking at doing a super-adobe but my wife thinks hyper-adobe is a better option.

    So I was thinking of doing super-adobe at the earth banked area and then finishing with a hyper-adobe. But I was thinking that the thickness of the 2 style would differ and the transition from super-adobe to hyper-adobe would create leveling issue?

    any thoughts

    thanks

    Don

    • I think it is a good idea to use the woven poly material against the earth bank, and you might want to put a moisture barrier between the earth and the bag material. Depending on the width of the mesh and the woven material, there may not be very much difference between the two. This shouldn’t present much of a concern, and may not even be noticed if they meet at a corner.

  3. Thank you for all of the great information you have provided to all over the years. Two questions on the mesh tubes / Hyperadobe:

    Would the hyperadobe using mesh tubes for a narrower wall provide a strong enough wall for an earth sheltered home? We are building in high desert with sandy soil on a slope. The north side will likely be completely buried.

    Also for fill, we could use scoria, but will more likely use our own earth on-site. If I understand right, with the daily temp. swings of the high desert (as opposed to long stretches of below-freezing temps), the heat sink might be more beneficial than super insulation…?

    • For retaining large earth berms I always recommend 24″ wide bags for extra strength. Curved walls with tamped soil are recommended in these areas. Add layers of strong plastic sheeting on the outside of these walls as well as French drain pipe and rubble trench. Study the Half Moon house in a previous blog post for tips. They also have a site on facebook.

    • Lightweight materials like this are most appropriate in cold climates. The energy savings would compensate for the cost of the materials. In your situation I’d use local clay subsoil because it’s cheap and plentiful.

  4. I am very interested in hyper adobe but wonder how it would perform in the humid tropics? I would think that the regular poly mesh bags provide a better barrier against excessive moisture. What are your thoughts?

    • Hyperadobe has it’s origins in the tropics (Brazil, etc.). That’s where it was invented. Mesh tubing is less expensive. Mesh fabric allows moisture to pass through (so does woven poly). Mesh is an ideal bonding surface for plaster. Use poly gravel bags on lower courses because they’re stronger, but for upper walls Kelly and I recommend hyperadobe. Use wide roof overhangs and raise the building site so the walls don’t get wet.

  5. on the note of using the mesh tube… we live in northern Missouri and intend to use scoria as the fill, in your opinion do you think using the mesh tube with long runs would make the vertical walls more stable than standard poly bags?… I was also considering using rebar or some other type of “stake” to pound down and connect the runs together instead of using twine. I had also considered stabilizing the loose scoria by adding clay, but that would add a lot of labor to the process… thought?

    • Scoria or any other loose fill is way less stable than tamped earth. But there are techniques like the one describe that will stabilize walls like this. Search our site for the keyword ‘scoria’ and you’ll see projects like the Casita. Watch their videos (Casita) and read the blog posts and you’ll figure out 99% of it.

      Clay can help stabilize loose fill, yes. But it will cut production in half and reduce insulation value. I think it’s easier to use rebar or bamboo pinning. Search our blog for ‘external pinning’ for one good method. Tying the courses together with twine is another helpful method. Putting plaster mesh on both sides and tying them together through the wall also helps a lot. Also, building in the round or adding curves, built in benches, buttresses, interior walls in strategic places, etc. all help.

  6. Ah, I figured I just wasn’t smart enough to connect the dots. I’ll have to wait for the “this is how you make the above material and stuff it into raschel bags/tubes” video. ;-)

  7. The pictured material doesn’t seem to match the desctiption. What is it’s composition? I know it isn’t, but it looks like injection-molded scoria. Why is it that color? Too many questions…

    • I was trying to explain how there are various ways to make lightweight geopolymer. This particular sample may have added foaming agents that make air bubbles or some other process that I’m not aware of.

  8. Every time I read about the advantages of hyperadobe I’m tempted, and I need a reality check – it is still true that you recommend regular non-mesh bags in seismic areas to allow the walls more “give” without breaking in an earthquake, correct?

    • We’re assuming regular poly bags are stronger (have more tensile strength) than mesh bags. But to really know for sure you’d have to check the manufacturer’s specifications. You may be able to find a strong mesh bag that’s nearly as strong as regular poly bags.

      • I thought the issue was not wanting monolithic walls that can’t flex with the tremors? That was what I understood from the EB Building Guide. Is this an “all of the above” situation?

        • Some of the solutions I proposed would flex with tremors (loose scoria, etc.). But lightweight hyperadobe can be used for many different purposes, including insulation in cold climates and creating super durable walls.

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