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Repurpose Used Materials to Construct a Green Home

 At Absolute Demolition we are always looking for new ways and ideas for our customers to take advantage of the used materials we have in our salvage yard. Whether you are just picking up fencing material to finally build a bigger yard for your dog, a new chicken coop, or adding on to your house we want the public to see what they can do to help with our environment. Here is an interesting article we found where you repurpose used materials to constuct, believe it or not, a home.

Papercrete

Papercrete is a fairly new ingredient in the natural building world. It is basically re-pulped paper fiber with portland cement or clay and/or other dirt added. When cement is added, this material is not as "green" as would be ideal, but the relatively small amount of cement is perhaps a reasonable tradeoff for what papercrete can offer. I have had a fair amount of experience with this stuff, and I would say that is has some remarkable properties. Care must be taken to utilize it properly, or you could be courting disaster. I am acquainted with both Eric Patterson and Mike McCain, who independently "invented" papercrete (they called it "padobe" and "fibrous cement") and they have both contributed considerably to the machinery to make it and the ways of using it for building.

The paper to be used can come from a variety of sources and is usually free. I've used newspaper, junk mail, magazines, books, etc., which I get from our local dump or from the waste bin at our post office. Depending on the type of mixer that is used to make pulp out of it, the paper might be soaked in water beforehand or not. My first mixer used a small electric motor mounted directly to a shaft with a couple of four inch square blades on it, rather like a milk shake maker. This shaft was suspended in a plastic 55 gallon drum where the mixing took place. After a year of making small batches with this, I graduated to a "tow mixer" designed by Mike McCain. I consider this to be the Cadillac of mixers because using it is so easy and fast.

It is basically a trailer made from the rear end of a car, with the part that would attach to the drive shaft sticking upward and a lawn mower blade attached to it. The blade is surrounded by a large stock watering tank where the mixing occurs. There is a baffle on the side of the tank to force the slurry back into the blade as it circulates. With this mixer (which I tow behind my Volvo station wagon) I can make three or four wheel barrows full of thick papercrete in about twenty minutes. I simply fill the tank nearly full of water, add about one wheel barrow full of dry paper, one sack of portland cement, and perhaps some sand, depending on how I plan to use the mix. Then I drive slowly around the block, back over a drain box with 1/8 inch mesh on the bottom, and dump the slurry into the box via a drain hole in the bottom of the tank. After about a half hour of draining the excess water from the slurry, the papercrete is like soft, workable clay, but not nearly as messy. This is the material that I used to plaster both the inside and outside of my earthbag house.


The slurry can just as easily be pumped or dumped into forms to set up that way. Eric Patterson makes adobe brick sized blocks of papercrete to build with, and mortars them together with a slurry of the same stuff. Mike McCain prefers to either pump the slurry into slip forms or make larger blocks for building. The addition of mineral material (sand, adobe, etc.) has the advantage of minimizing the shrinkage as it cures, making the final product more durable and fire proof, at the expense of slightly less insulating value and more weight.

Cured papercrete acts like a sponge unless it is coated with something to stop the entry of water. In my earthbag/papercrete house I have allowed the papercrete to breath fully, so that it absorbs an enormous amount of water when it rains. This is not a problem for me because there is nothing in the wall that would be damaged by water, even if it got past the papercrete layer, which it rarely or never does. It is a whole new concept for a roof: a sponge that welcomes the moisture, and then simply give it back to the atmosphere through evaporation. I have had large cracks (up to about 1/2 inch wide) in the initial layer of papercrete on the earthbags, and still have not seen any water getting through into the house.

Other properties of papercrete are:
1) It is dimensionally very stable both through the process of taking in moisture and drying out and in a wide range of temperatures.
2) It will hold fasteners to some extent, especially screws, without cracking.
3) It is highly insulating (about R-2 1/2 per inch).
4) It does not support flames, but will smolder for days if it does catch fire. The more cement and mineral material that is added to the mix, the more fire proof it becomes.
5) It will support molds if it remains warm and moist for too long.
6) It will wick moisture from the ground into the wall if it buried in dirt.
7) It becomes soft and will deteriorate if kept damp (especially underground) for too long.
8) It resists rodent and insect infestation.

Paper adobe is similar to papercrete, but instead of cement used to bind the paper fiber into a solid, clay is used as the binder. This can work well if the material is kept absolutely dry; otherwise it will become soft and could deform.

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For more information on ideas like these go to www.papercrete.com