Hyper-wattle Update

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.]

Read Full Post »

Hyper-wattle Wall Test

Hyper-wattle wall test with 170 lbs/linear foot on 6” diameter wattle tubes

Patti Stouter just tested her hyper-wattle wall system that’s she’s building at her home in New York. She’s published the results on her Hyper-wattle proposal at the $300 House design competition. She’s been in the top three consistently and there’s a very good chance she’ll win first place. I believe her project is the best and deserves to win. Please vote if you have a chance. Like I said earlier, every vote for one of the sustainable designs is a vote against the industrialized solutions.

“Only a hint of how strong these wattle walls might be. We just placed almost 170 lbs/ linear foot on a 30″ high wall portion made of tiny 6″ diameter wattles. This is the one seen in the middle right on plate 6, with half to 5/8 inch diameter diagonal branches tied in about every 12″. The wattle appears very dry, and we used some room heat and a fan to hasten drying. It has a base layer of earthen plaster that is still damp, and has some cracking. So this could be stronger with a finish plaster layer that is totally dry. [Ed.: Yes, much stronger.]

At 90 lbs per linear foot we could measure less than one percent compression. Roof weights for an ordinary asphalt shingle roof with framing and plywood on a 10’x10′ building (3 x 3m) would be about 4 lbs per linear foot.

If two percent compression is acceptable, the building should be able to hold up this type of roof with a snow load of 20 lbs, what my region of southern NY gets.

This needs more testing, and lots of discussion of wind forces and shear strength. But for regions without snow, does anyone else agree with me that this kind of wall will be able to hold up a light roof? [Ed.: I say yes, especially when you consider the finished plaster will be thicker. Roof loads will be transferred through the rigid plaster skins, not the wattles.]

It takes one large straw bale to fill enough wattle for 2.7′ length of wall 5′ high. That’s a bit of straw, but if one can build after the harvest, and straw is a waste material, it might be worthwhile. [Ed.: Baled straw isn’t required. Most areas have some type or grass, straw or reeds that will work.] I like straw-bale housing, but this dipped clay technology might allow people in very humid regions to have a less mold-susceptible house. [Ed.: And the narrow walls take up less space.]

I’ve rushed this first test to have some data before the Jovoto contest is over. I want to put a finish plaster on this little panel and then compress it till it falls apart. I also have a larger wall panel that I hope to do a shear test on eventually, when it’s dry. Today I’m going to do the second layer of plaster on it.

The side photo shows that this little wattle wall wasn’t even perfectly straight. I hope to be able to include some wattle panels in the shed I’m building now for gable walls. I’m going to test out doing a trash wattle panel flat on the ground and see if straw-clay plaster stiffens it up much.

Personally I like traditional earthbag because it’s simple and fool-proof. But there are many places that some different materials are more easily accessed than subsoil.”

Read Full Post »

New Earthbag Houses in Bangnol, Haiti

From Patti Stouter:

The cardiologist with the Haiti Christian Development Project who helped get the Bois Marchand earthbag house built near Gonaives, Haiti sent a link to some photos- 2 are the new earthbag buildings at a small village called Bognol. I helped to design the site and these buildings. Earthbag houses bring great excitement to the community and demands for expansion.

At Bangnol, we went in the two new earthbag houses nearing completion (and enjoyed the 10-15 degree cooler temperatures). These are two-room houses that are bigger, have better ventilation and cooling than our first house. Thus far, they have cost about $1850 each to build, and we feel confident that their final cost projects to be under $2000. At the earlier meeting with the elders, we spent a great deal of time talking about how to determine who would get the houses, and we discussed how these subsidized houses could be built. Within a few days, the houses should be completed. We have been contacted by Habitat for Humanity who are interested in our houses because the cost is only 1/3 of the cost of the houses that they are building in Henche, Haiti.

Bangnol, Haiti site plan by Patti Stouter

Photo credit: David Smith

Bangnol, Haiti Project page

Read Full Post »

Raschel Mesh for Narrow Walls

Raschel Mesh for Narrow Walls

Patti Stouter sent me this news about raschel mesh from a supplier in Canada that works perfectly for the narrow rubble walls in her Totally Tubular design. She builds hyper-wattle — tubes of lightweight insulation — on top of the narrow rubble walls.

“The 18″ wide raschel got here last night and I tried it out today. It is strong enough to work with easily, none of my soil fell through (only a little dry sandy soil will fall through I think), and it seems to be a good size. It tamps to 12″ wide at 4″ high or 13″ wide at 3.5″ high. I think this is acceptable.

If I remember right this is $170 ($Canadian) for a 1000 m roll plus shipping. It’s called 18″ raschel mesh.”

Contact: Maurice Wilson, Bag Supplies Canada, Stratford, Ontario
1 519 271 5393

Update: Maurice just found out that the raschel mesh had been misunderstood. His supplier thought he wanted a flat length. So to get a tube, he’ll have to charge 237 $CN for each 1000m roll plus shipping.

We need to modify the price listed on the blog post. He’s offering UV resistant raschel mesh 18- 20″ wide.

If shipping is $60 each (a little low, but people will often buy 2 rolls for a modest house since 1 roll will build only 120 lf of 8′ high walls) then that will end up costing about $109 for a 10′ x 10′ room.
Calearth’s tubes plus barbed wire cost about $390 per 10′ x 10′ room.

18 x 30 bags bought at 30 cents each including shipping will cost with barbed wire about $137 per 10′ x 10′ room.

If someone uses misprinted bags for 20 cents each including shipping it will only cost $97 with barbed wire. But these will not be UV resistant.

So the raschel mesh is much quicker to build with, lighter to transport, UV resistant, and costs just 12% more than the cheapest non-UV bags that can be bought in the US. He’s ordering 20 rolls for the first shipment, so people may want to place their orders with maurice@bagsupplies.com.

Read Full Post »

Hyper-Wattle on Rubble Bags

Totally Tubular: Hyper-Wattle on Rubble Bags

Here’s Patti Stouter’s entry for the $300 House design competition. Rubble bags on lower walls provide a solid, flood resistant wall. Hyper-wattle provides lightweight insulating upper walls made of mesh tubes. Thin walls conserve space and materials, and take less labor. Her design is one of only a few in this competition that could actually be built for $300 or less.

Patti’s project is getting rave reviews. Over all, the jurors have posted very few comments, but RSmith posted this comment: “Genius! I love this concept. You are maximizing the most available resources: Human labor, earth and trash! This is one of the best design I have seen so far! …”

This could very well be a winning design. Please vote as soon as possible. There are only a few days left.

Update: Voting is getting vicious. There appears to have been a coordinated attack against all three of my designs in the last hour. All three designs suddenly plummeted in unison by about 20 points each. I’ve been cautioning people about some of the drawbacks to other designs and this has likely triggered some hard feelings. If you haven’t voted, please help support our designs.

RUBBLE BAGS:
HEAVY BASE WALLS
13” THICK BAGS FILLED WITH RUBBLE OR GRAVEL AND/ OR SAND (OR OTHER MASONRY)

A WATER-RESISTANT FOUNDATION WALL
Low height allows thinner width
Barbed wire between courses for tensile strength
Less expensive than metal gabions
Doubled poly bags for 3”- 4” coarse rubble
Finish with cement stucco

LIGHT UPPER WALLS
8” THICK MESH TUBES FILLED WITH STRAW OR CHIPS, DIPPED IN CLAY SLIP
NATURAL FIBERS RAISED ABOVE WATER AND INSECTS AND COATED IN PROTECTIVE CLAY; R-12 TO R-16
LIGHT CLAY IN PLASTIC MESH TUBES
 NATURAL, SUSTAINABLE MATERIALS
 ADAPTABLE TO DIFFERENT SHAPES
 STRESS-SKIN TECHNOLOGY
 LOW-TECH AND SIMPLE
 USING LOCAL LABOR
 FINISH WITH LIME & EARTHEN PLASTERS

Read Full Post »

East Coast Earthbag Workshops

This is very good news for those who live on the east coast. Patti Stouter, now one of the knowledgeable leaders in earthbag, is offering $50 one day courses in New York. She’s been an enormous help on projects in Haiti and on my book, and has my full support. The text below is from her website (which is growing into one of the best sites).

Earthbag appears to be in a phase of quickly increasing spread. Earthbaggers willing to answer questions get more and more queries from people desiring to build cheaply in different parts of the world. Information about building with earthbag is available for free on the internet, but many funders seek an experienced builder to supervise their project.

Many owner-builders jump in and hone their skills on a small building. But aid organizations want to know their money won’t be wasted or their project fail over small mistakes. They’d like to see and experience this material they’re telling their donors to use. So much about building is a matter of discernment, and the two most basic questions remain:
Where can I see a real earthbag building?
Who can teach us how to do this?

Most earthbag trainers seem to live and work in the western US: CA, OR, WA, NM. Others are in Australia or Poland or Thailand. Some charge high fees for a week or longer introduction to earthbag. Homegrown Hideaways began an excellent weekend program in Kentucky this past year, helping to bring the earthbag center of gravity for the US into the midwest. I logged a lot of hours and miles going down to Kentucky to get some experience.

Since then I find myself doing a lot of long distance earthbag mentoring of builders working in Haiti. It’s time for some training on the East Coast, and an even less expensive option. I’m starting a series of Saturday workshops to introduce earthbag topics and teach important skills. No, you won’t be a master builder when it’s done. But for $50 a course you can learn and decide if it’s worth taking further. Take one or several, and see what you think. Popular sessions will be repeated, or custom sessions can be fit into a morning.

Current workshop schedule is at SimpleEarthStructures.com

Read Full Post »

Earthbag Newsletter

Patti Stouter's earthbag newsletter recaps news and events in the developing world.

Patti Stouter has published a new earthbag newsletter that recaps recent news and events in the developing world. This is a great way to spread the word. Feel free to share with others.

Read Full Post »

Friction and Tensile Strength of EB Components

Patti Stouter has published another earthbag technical report. It is a summary of the state of testing to date, and also covers some of the codes related to earthbag. The following information is quoted from this report.

According to the new international earthen building standards, if earthbag walls with some reinforcing have shear strength equal to or greater than reinforced adobe they can be designed for building structures even in the most risky seismic regions. Since shear strength is related to friction between courses, soil filled poly bags were tested by a simple tilt table method to discover the approximate coefficient of static friction between the bags with barbed wire. Additional tests used barbed wire and metal pins, or pins alone. The force needed to pull barbed wire out axially from between bags was also tested.

– Results from more than 20 tilt tests indicated that full, moderately firm bags have coefficients of static friction between 1.5 and 1.9, up to 3 times higher than those needed to create an unreinforced geo-cell wall.
– Higher coefficients of friction (up to 2.7) resulted from providing small metal pins with 2 points. Length of barb did not appear to affect the coefficient of friction.
– Results from two axial tension tests indicated that barbed wire does not pull out until the barbs bend. Although static friction was overcome at 60- 80 pounds force, 120 pounds was required to remove the wire completely from between two partially cured bags.
– Instead of tearing the bags, all of the embedded barbs appeared to have bent.
– Barbed wire contributes to both the friction (related to shear strength) and the tensile strength of earthbag walls.

The full report is accessible from EarthbagStructures.com and EarthbagBuilding.com. Here, you can find all earthbag testing reports for easy reference.

Read Full Post »