'Sustainable Building' Construction and Renovation

Sustainable Building

But, if you want to do something really low cost, but highly effective, what kind of options exist? First, always look to the local surpluses.

Uruguay grows wheat, and rice for export. Wheat straw is usually either burned off or tilled under. Sometimes it is baled for sale to animal handlers, like chicken growers. I haven't yet been able to find out the quantity of standard bales produced each year or the cost. Maybe one of you guys knows? In the States bales of wheat straw run from $1.00 to $8.00 depending on transportation costs.

Another waste product that is mostly free in Uruguay and the rest of the world is Rice Hulls. Uruguay produces about 200K Metric Tons per year. They don't burn easily, to say the least, so are expensive to get rid of. They do have extraordinary insulation properties, especially when compacted.

Another waste product that is growing is saw dust. There is a market for saw dust here, but the players aren't very reliable, so the saw mills are usually eager to give it away.

Beyond that there is rock dust from all the mining, sand, and just plain dirt.

Because of the Animal Feed and Gardening Industries, and the annual flooding in the North River towns the Bag Manufacturing Industry has blossomed. There is a very wide assortment of bags available made of lots of different materials and weaves.

With all the above considered, I believe the lowest cost housing and small commercial is likely to be the Earth Bag concept. The only costs are windows, doors, plastic bag rolls, and barbed wire. Oh, and enough cement to do your slab. For a fancy one you can add simple metal wire, or wood trusses and a Foam backed roof panel setup and you're done with material costs. The finished job is coated inside and out with 'Mud Plaster' that you make on site from the dirt you've excavated. This makes a thick, sturdy, moisture proof building.

For Barns or other large open structures, the wheat straw concept looks good. They can be built as a 'Load Bearing' construct, where the bails are placed on a slab and tied together with re-bar and all thread to a wood top cap. Then the same style roof can be applied. The same mud is used. the cost is a bit higher, but seems to work very well where wheat straw is abundant.

When an Earth bag home is finished it is about R-30 in insulation value, if very high R-50 or greater insulation is desired, just make a simple frame on the inside and compress rice hulls into it. I like this partly because inside this inner wall one can run all the plumbing and electric. also, it is easy to finish off with a standard appearing interior wall appearance.

Of course, the rub is that one thing required is lots of work, either stuffing bags or stacking bales. But, hey that's what Pizza and beer is for, right?

Most bales down here are of the cylindrical 1 tonne variety rather than the small rectangular bales which are suitable for straw bale construction. I grew a fine crop of long straw variety of winter wheat this year, had a local contractor bale it for me and sold the 1 tonne bales off the field for 12 U$S each (being 7 U$S baling costs and 5 U$S for me.) I'm sure there must be small traditional balers around but I don't personally know of one.

I see that from next year us farmers are to be encouraged to grow cannabis as a green fertilizer crop. In my experience of building eco-houses in the UK, there is no better more durable straw substitute than hemp stalks in baled format but I don't yet know if the new regulations will allow the harvesting of the stalks.

I was fortunate in having a lil ol boy who makes bricks living nearby who made me all I used in renovating and extending my house. It turned out that his great grandfather dug and made the original bricks used in the oldest part of the building... I'd never seen a 15 inch brick before :-)

The process of digging the clay, rolling it, cutting the clay bricks, stacking them with a load of firewood, coating the stack with more clay, firing it, unpacking it and delivering the bricks on site involved two men and a horse so except for the ol boy's mobile phone, the whole process was carbon neutral. No motorized transport was required.

I know a couple of Uruguayan eco-architects (one in MVD and the other here near Colonia Valdense) if you'd like their contact details to swap ideas.

I've seen a few of the old style bailing machines around in Durazno, San Jacinto. Saw someone with a truckload of wheat straw in the old bales on his truck. Just don't yet have a feel for the cost.

I like the idea of the old 'fire it yourself' bricks, but that's not going to work for me as I'd have to talk your neighbor into moving! Another plan talked up a lot is the Rammed Earth block concept. That might work. I did like the load bearing straw bale method best for Galpones, not just because working in one during the winter is so much more a pleasure, but it is also very good if a corner might be used for a worker to live in.

The idea with the hemp is to till it under in order to enrich the soil, right? That, then, would need to be done when it is green most likely. Would it still yield straw? Do you know why they chose Hemp? The Fibrous variety of Hemp does grow enormous, something like 3 meters high, right? My guess would be to raise the organic matter content of the soil.

They'll probably have a bunch of yocals trying to smoke it, even though there isn't any (or hardly any) of the secret ingredient in that kind.

In some countries (Australia & U.S.) they're making straw filled 4 inch thick panels that fit into pre-made metal channel frames. I'd like to see someone make rice hull filled panels in 4 & 6 inch thick sizes. 200K Tons per year of one of the best insulating materials on Earth, just in Uruguay alone!

I haven't made detailed enquiries elsewhere but I can think of at least 12 lil ol boy brick makers within 10 kms of where I live so I'd assumed that you'd find them wherever there are clay deposits with a handy supply of eucalyptus nearby for the firing. They seem to work outside "the system" so you don't find their products in most barracas... you have to ask around locally.

Bernard Mira (a local eco-architect who worked in California for a while) is a great believer in unfired adobe-style bricks. He made his own to build his office.

The usual regs for hemp growing elsewhere is to set a date for the cutting of the crop before it flowers in the autumn as its the female flowering heads that are popular amongst smokers. From the handout I read in my ag co-op, the plan seems to be to grow the crop early in the growing season, use forage harvesters to shred it and plough or rotivate the remains into the soil with a cash crop to follow on as its practical to grow two crops per annum here. Hemp/cannabis of the sativa variety grows at a furious rate and has the advantage of suppressing most field weeds. As said, its going to depend on the precise regulations. I'm fortunate in having some very productive land but I'd be the first to admit that the soil structure and drainage would benefit from additional fiber.

I often despair about ROU attitudes towards insulation in buildings. Even when you offer practical demonstrations of the huge advantages with respect to personal comfort and saving money on energy, a blank look comes over locals with mutterings about how they "can't afford it." The ROU is awash with agricultural products and by-products ideal for producing insulated sheeting but as far as I can tell, none of it is processed. The few insulation materials generally available are expensive imported chemical based stuff like expanded polystyrene (espumaplas) and polyurethane. So ingrained are the attitudes that it would take a major education program along with demonstration buildings where visitors could see and feel the difference to change hearts and minds but the politicians I've cornered and bored over the subject seem to share the general views of the people.

You can take a horse to water but you can't make him drink :-)

On the insulation stuff, the non-fired rammed earth block to me is the most aesthetically appealing, but the earth bag can be sewn parallel to the wall to be filled on the outside with Rice Hull and the inside with earth, thereby giving a very sturdy and well insulated wall at extremely low cost. I like that.

• Characterisation of hemp (Cannabis Sativa L.) roots...

Bob Gieser

• Nudura Insulated concrewte forms

I think it is important to spend time HERE to learn how they do things HERE and from there decide what your options are.

Everyday I see cement trucks pouring cement at construction sites here. In several years of living in Costa Rica all I saw was the small mixers, not once a cement truck.

The "don't compare" comment is all inclusive, ie: food, language, culture, climate, geography, people, and everything else you can think of.

My local workers had a good grasp of preparing sturdy shuttering (formers made from old floorboards, ) "knitting" the steel rods into complex shapes and of mixing and pouring concrete. My only criticism was their glacial speed but that was partly because of a lack of rentable plant/machinery and a lack of prefabricated materials like reinforced concrete beams.

I ask because I and some investors plan to come to Uruguay early next year to look into purchacing a farm and beginning production, and I'm working on the business plan and investment portfolio and need to form a timeline.

Thanks

Rich

Things develop at glacial speeds down here so I can't see hemp being approved for other uses like fiber production, horse bedding, quality paper making or for construction purposes for many years.

I'd like to be wrong but I fear that I'm not.

Anyone have any contacts, people who have done it, eco architects, etc.?

• thenaturalexpat.com

Please send me a private message if you'd like contact details for either of them.

I am coming to ROU in the next couple weeks to look at possibilities of emigrating and have vast experience in eco construction.Having built my own SB house and then contracted doing mainly Cob houses from small 40 msq to 200msq houses . I would be very interested in networking with similar minded people and projects.

I'm really interested that all the rice straw is not being used more productively

With the global downturn I've had to concentrate on wooden decks but the passion is sustainable building .Use what the enviroment gives you is my guiding principle

Regards

Mark

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