Superadobe is a fun example of a "solution looking for a problem," and I don't think that's categorically a bad thing.
These undeniably have a cool tatooine look. For someone with a bit of land (even a nice sized garden) in arid climates, this could be a fun project to do with teenage kids. Do the workshop(s), plan a structure and build something cool. If you can get salvaged windows, doors and a floor it could be a genuinely useful structure like a studio or fun guest cabin.
Landscaping would also be a good project.
It would be cool if they had some photos of structures, and the number of hours it would take a couple of amateurs to build it.
The construction schedule depends on how large the project is and how much labor is available. There are optimal numbers of personnel if the project is to be built without any kind of mechanization. The rate at which the mix is produced dictates how fast a project can go. The optimal number seems to be 7 persons where one or two are making mix and the remainder are split into two groups laying two bags at the same time. From past experience there are some fairly predictable estimates as to what can be achieved: 1) Three reasonably-fit persons can work very efficiently laying 100 linear ft of bag per day. 2) A double eco-dome (see web-site under "buildings and designs" can be built in just 10 weeks. (This is bag work alone - and it is estimated that all finish work will take about the same amount of time.) There are, of course, time-saving techniques which are discussed during workshops and training sessions.
Though, one of those double eco-domes is a pretty ambitious project for a weekend DIY-er. It's a whole tatooine house!^
What I had in mind is say, a 3-4 meter (diameter) dome with one door, one small window. How long would that take 1 parent + 2 (lazy goodfornothing) teens? Another small project might be 1.5m walls to surround an existing gazebo or emote other backyard structure. IE, something that's undeniably a building but is accessible, ideally as far under 1,000 man-hours as possible.
^If you build one of these, please don't leave out the below surface courtyard. It's essential!
Here's a similar system for building retaining walls: http://www.envirolok.com/ – using perforated bags allows for drainage, and plants can recolonize the stabalized wall.
I've always preferred compressed earth blocks to superadobe (http://opensourceecology.org/wiki/CEB_Press). I think CEB has more potential to replace western buildings at a lower cost and low carbon footprint.
Nader Khalili's other design, the Geltaftan[0], is worth mentioning. These are essentially clay buildings which are then fired to produce ceramic houses.
The biggest problem with earth building, which I looked in to quite a bit a couple of years ago, seems to be the lack of ventilation and drainage options relative to other types of building. You still need foundations. Yes, you can make it work. No, it's not always suitable - right tool for the job.
Much like other alternate building techniques (straw bale, etc.) it faces significant regulatory challenges in many jurisdictions due to a lack of familiarity with structural properties and the variable nature of the inputs (what type of clay, straw, etc.). Usually it's cost prohibitive to try in cities, because the labour costs are higher. In those situations, prefabbing concrete/other types of slabs and dragging them on site can be a really fast and cheapish way (though environmentally questionable) to get a house up. In general architects and engineers are also far less familiar with the alternate techniques.
As for the 'tattoine look' starwars reference, that was actually filmed in the underground houses of Matmata, Tunisia ... which I photographed during the Tunisian revolution for Wikipedia Commons over here - https://en.wikipedia.org/wiki/File:Matmata_Panorama.jpg
>Long or short sandbags are filled with on-site earth and arranged in layers or long coils (compression) with strands of barbed wire placed between them to act as both mortar and reinforcement (tension).
Why not? This seems like the kind of idea that patents are made for.
* It's cheap and easy to implement and copy
* It seems obvious once you tell it to someone, but apparently it took space exploration research to come up with it.
You can't keep such an invention secret, but it might have taken a lot of trial and error to come up with it, so in that sense, why shouldn't the inventor have the possibility to monetize it?
There are a number of these sorts of historically-inspired alternative building techniques. Others include rammed earth, Earthships, straw bale, and monolithic domes.
I think they are all cool in a pop-ecological sense, and do have some compelling advantages. However, I can't help but think that there is a reason we've settled on our current wood or steel frame housing. If I had to guess at those reasons:
Aesthetic longevity. No one doubts that a concrete dome or pile of sandbags will last a long time. However, I suspect that keeping the appearance nice would involve much more work than a typical home siding system. In addition, while some people might like sci-fi or "hippy-commune" aesthetics in their neighborhood, I would suppose that most places would hold new construction to a somewhat higher (read:expensive) aesthetic standard.
Post-construction flexibility: Want to change the floor plan a bit when moving into a new house? Many of these alternative methods result in a building that is a bit more "set in stone" than framed buildings. Also re-configuring plumbing, electrical, or duct-work is likely to involve a lot more effort than re-hanging some drywall.
Multi-story limitations: some methods do allow for multiple stories, but it seems to dramatically increase the cost of construction, and the number of floors is usually limited to 2. This means that the alternative building styles work best in places where space is cheap; footprint constraints would be serious problems (see also: alternative methods produce much thicker walls.)
All the pictures on the website seem to be taken in arid climates. Does anyone know how well Superadobe is suited to more humid/cold climates (e.g. Scandinavia)?
Adding layers of insulation on the inside seems non-trivial, given the dome shape and the already thick walls.
Although generally and historically associated with arid, desert climates, earth architecture and specifically super-adobe construction is as suited to cold and wet climates as any other type of construction. With regard to water issues it is necessary to properly waterproof the building and this is achieved in a multi-elemental approach which is discussed and demonstrated in detail during our workshops and training sessions. The question of water is not so much how do we protect the building from water but rather how do we harvest the resource of water from the building!
I'd also suspect, generally, that drainage and humidity control would be issues in moister / wetter climates. Cold ones also, as condensation from warm interiors onto cold surfaces will likely be an issue.
> The question of water is not so much how do we protect the building from water but rather how do we harvest the resource of water from the building!
"Harvesting" water from the building is certainly an interesting idea!
> as condensation from warm interiors onto cold surfaces will likely be an issue
That's a good point.
What's your opinion on the feasibility of this building technique for urban areas (in say, Western Europe)? I can imagine it to be hard to get a permit for building such a dome, as it doesn't blend in with the surrounding structures. Other than that, the low cost make it very attractive.
I really don't see the method as appropriate for dense urban construction. It seems far better suited to rural spaces with little access to modern building materials. Though this really isn't my bailiwick.
There's a design for dense modern urban areas: it's brick-and-timber multi-story construction. You'll find it evident throughout Europe, with basic designs largely established by the 19th century if not before. The advantage of such construction is that it greatly minimizes land use, and hence transportation, a major concern for urban lifestyles. Designs which require large areas, aren't amenable to dense and multistory construction, and whose construction itselft is disruptive to adjacent properties (digging for earth fill in this case) strike me as a poor fit.
In rural areas it might work, though again issues of moisture and cool climates would concern me.
There's also an existing high-density earth-based construction model, the pueblo:
I believe that a common method of insulating mud-built buildings in cooler climates is mixing straw with the mud. There's probably some method of incorporating something similar either inside the bags or as an external layer. This wouldn't have to be straw, it could be something longer lasting with similar thermal properties.
I heard about this first a few years ago in the context of refugee camps. I think the idea didn't take off (not many countries wants refugees building weird buildings in camps), but the selling points is that all you need to bring in as materials are the bags, barbed wire and cement.
The bulkiest material is earth, which can be dug on site. Cement is optional, but improves structure's longevity. No bricks, sand/aggregate. Nothing to manufacture (other than bags). Most building methods require a building material industry behind them. Here a truck with a few thousand dollars worth of materials and basic tools is all you need.
Labour is the main ingredient and non specialized labour is often available.
^1,000 yards for $1,000. You can get a large house-worth of bags for that. Have 10 kids? Make each kid lay 100 yards!
^I don't think you can separate how it looks/feels from the rest of the project. I think the reason superadobe keeps coming up in the internet "check this out" world is because of this. It's looks and feels like an accessible DIY project you could be very proud of.
I think it's more interesting to build temporary dams using this. It could be more robust than using ordinary sand bags. Their licencing could be interesting in this regard too:
"Superadobe is a patented system (U.S. patent #5,934,027) freely put at the service of humanity and the environment. Licensing is required for commercial use."
The only entity that can sue you for infringement is the patent holder. So you could send them an email and ask them whether they would sue if you sold your home.
"Commercial use" in the US typically means designing and operating a business around the idea. It would be up to a judge to decide. Here is a law cite:
Like everything to do with patents, fly low and nobody will bother you. The chances of being sued if you build a single house and sell it are somewhere between zero and 1 / infinity.
I've heard it mentioned as specifically a tool for refugee camp type situations, when you have a lot of warlike supplies (bags and barbed wire) to hand, and a lot of people to house in a hurry.
"Cal-Earth’s sandbag structures, reinforced with barbed wire, have successfully passed tests for California’s high seismic building codes, making them resistant to earthquakes as well as fire, flood, and hurricanes. "
A properly tensioned dome structure with multiple bonding between layers, particularly if continuous or long bags / ropes are used in the coils seems to me a possibly robust structure.
An unmortared or weakly-mortared square brick or stone structure is about the worst option for a quake. All the compressive forces are vertical only,and there's not a whole lot to keep things together when shaking starts. Individual structural elements (bricks or stones) are small and easily shift relative to one another.
Though this doesn't show direct earthquake effects, this post-quake demolition in Christchurch demonstrates how much stronger reinforced concrete is than unreinforced brick. The demo would have gone far faster with a jackhammer attachment.
So they're building houses out of sandbags? What if the plastic bag breaks? Why don't they coat the whole structure in something a bit more resistant to a kid with scissors?
The plastic bags are only intended to be exposed temporarily. If the structure is intended to be permanent, the plastic bags are plastered over (from the article):
> For permanent structures, the synthetic bags are plastered over to provide an erosion resisting layer, or they can be removed when the stabilized earthen filler is cured.
These undeniably have a cool tatooine look. For someone with a bit of land (even a nice sized garden) in arid climates, this could be a fun project to do with teenage kids. Do the workshop(s), plan a structure and build something cool. If you can get salvaged windows, doors and a floor it could be a genuinely useful structure like a studio or fun guest cabin.
Landscaping would also be a good project.
It would be cool if they had some photos of structures, and the number of hours it would take a couple of amateurs to build it.