Here’s the latest from Patti.
“People building with trash have relied on bottles filled with sand or adobe or film plastics to provide strength in infill walls. They have needed either cement mortar or chicken wire to hold the walls together. Some good info on previous projects is at:
http://inspirationgreen.com/plastic-bottle-schools.html#jfafa3e6aa
Because of the strength of the mesh I’ve been given, softer trash can be used and chicken wire is not necessary. If you firmly stuff #5 and #6 small containers (yogurt cups, scraps of everything else) into an 8 inch diameter wattle it becomes slightly springy but pretty firm. I also used wattles filled only with foam- which ends up a little softer. I alternated hard trash wattles with foam wattles in a row.
I made 5 tubes each 4′ 6″ long and sewed one edge to the next tube at top and bottom quarters. Then I turned the tubes over so the sewed edge was on the floor, and used a sticky clay plaster with straw for fiber to fill the nooks left between tubes. On that I added enough light clay plaster (like straw clay, but with a slightly stickier/ thicker clay slip) to level the surface out. The clay plaster seems to adhere well to the mesh. This is a strong black UV resistant mesh from Master Net Limited (of Canada). A small order would cost 9 cents per foot including shipping. Smaller 6″ diameter mesh could cost about 5 cents per foot and might result in slightly lighter panels.
I find I can lean this wall panel upright pretty well. When several tubes are attached together they brace each other somewhat. It is conceivable that bundles of 3 smaller tubes could be used as piers to stiffen a wall surface. With a cast cement or poured adobe base, this material could be made into panels that could be easily stood up and fastened into a structural framework. Pre-sewing and doing infill plastering seems to make it easier to keep the material flush and make a neat wall. There may be a chance that fully plastered on two sides with lime plaster and/ or cement stucco these wattle portions will become strong or stiff enough to function as bearing wall in a small building. It could be that like foam core, although the interior is not terribly strong or stiff, it can brace two exterior skins. But it can certainly make a good infill wall.
I’m thinking about piers of Harvey’s Ubuntu-blox with my vertical trash wattle panels between. This wall would be flood-resistant, have a decent R-value, light enough to weather earthquakes well, and be very inexpensive. I really want to make a dent in that Great Pacific Garbage Patch. I know others do too. So let’s stop feeding it and start using it for shelter.”
Please support us in our quest of promoting low cost sustainable housing for the world’s poor by voting in the $300 House design contest. Patti has a very real shot at winning this. Her project is Hyper-wattle on Rubble Bags.
Patti’s web page has photos and more details.
[Note: Max Bldg., who’s been causing so many problems in the contest (see blog post below about vote stuffing), is still up to his dirty tricks. Let’s hope the jurors adjust the ratings again to compensate for the fraud. But just to be sure, please vote if you have a chance.]
Follow up. I just submitted a question, then found this from Patti S. from about 3 years ago: (I cut and paste below)
Patti Stouter
about 3 years ago1
“So glad you’re moving up in the rankings, Harvey. This is a simple, practical solution that can really make a difference for slum dwellers. When the structural and R-value results come out, this is going to be way above most other ways of building. I’m still hoping to put second storeys of Ubuntu-blox on top of earthbag bases for Haiti. The only thing stopping me is that I need more detailed structural testing data to size the earthbag ground level walls.”
She was considering the “second story” issue long ago. I would still love to hear your thoughts. Thanks
Harvey is using opposing rebar pins tied together through the wall. This method is incredibly strong. It can be used with thin wall earthbags, hyper-wattle, straw bales, etc. You can see Harvey’s Ubuntu blox earthquake test video on YouTube. It’s a real eye opener. This is the method I’d recommend. It’s basically double skins of ferrocement. You can even get engineering approval if needed.
Owen, in reference to traditional earthbag technology, in the past you have advised against building two story houses in earthquake prone Haiti. I understand that–8 ft high of heavy earthbags is one thing, 16 ft high is something else! And I believe you allowed the light weight second stories built of things like bamboo might be ok. Upon initial investigation, I could not find indigenous construction grade bamboo in Haiti.
Might the hyper wattle skins on straw or trash bags be a way to construct two story homes in Haiti? Might a second story of these light bags be likely, or would you prefer to only use the light bags as the upper half of a one story building?
I ask because some in Haiti to whom I have shown your house plans prefer the two story ones. While you likely can’t say until all the research is in, do these lighter walls hold hope for second stories in Haiti houses?
That’s a tough one. It all depends on several variables — workmanship, building details such as tie-downs and pinning, length of walls, building shape, etc. So I’d say it’s possible given the right design, but risky without.
Builders Without Borders is doing a project in Haiti now in partnership with Help Hayti with bamboo. Check them out.
http://www.builderswithoutborders.org/
http://www.helphayti.org/