IN THE COMPANY OF "ODD-BALES"
by Don Stephens, USA
Some straw bale folks are such purists. As soon as I mention another wall material, their eyes glaze over with instant loss of interest. But in MY design studio (confession time), field strawbales are not looked upon as the only answer, but rather, just one of many options on the "design palette". A very good one to be sure, but NOT the only game in town. So when I encountered the high-density straw-blocks, I was also open to their possibilities. And there are some other even stranger eco-building units on the horizon that would also seem to show promise:
TIRE BALES - Most green builders and designers are familiar with the long-used technique of building retaining walls of used tires rammed with earth. Even if they hadn't already encountered this system elsewhere, Mr. Reynolds' EARTHSHIP books have certainly promoted it in detail.
But the first time I saw mention of "tire-BALES", it caught me by surprise. That was in an email from Michael Shealy, a self-confessed "generic" earthship builder, back in June, 2002. He was inviting Organic Architecture list members to visit his page at TouchTheEarthRanch.com (updated link) and of course, I did posthaste.
It explained that "tire-bales" were just that, bales composed of 100 used tires rammed together in a big hydraulic press that squeezes them down into blocks about 4 1/2' x 5' x 2 1/2' high, weighing around 2,000 pounds each (about 36#/cu.ft.) and contained by five square-knotted 9 gage galvanized or stainless steel wire bands. Hardly the sort of thing you and a buddy toss off your pick-up and into a wall by hand; rather they're hauled to the site on a low-boy trailer and placed with a boom, fork-lift, hay-grapple or backhoe.
They're being sold for from $5 to $20 per bale, depending on supplier (plus the makers usually get a buck a tire from the retailers to haul them away.) To see if anyone in your area in generating them, check in the yellow-pages under "Tire Disposal", or contact tire-bale press makers on the web for their units that have been sold to recyclers near you:
TireBaler.com and TireResourceSystems.com (now a dead link).
A test of bearing for the Minnesota Department of Transportation indicated about 12" deflection at 13,520 psf or less than 2" per ton. From thermal modeling done at the University of Colorado Department of Mines, an encapsulated R-value of about 8 per foot was derived (figure 20 through the height or 32 across the width). And since they have some rather large voids, filling these with something like perlite or sawdust and protecting from moisture penetration should boost that quite a bit.
They've already been tested in several ways. In Colorado, Minnesota, Arkansas and New Mexico, they've been used successfully in road subgrades, in historically problematic locations. A "surface" home was built of them in the midwest several years ago, and now Michael Shealy had developed an earthship-type design using them in lieu of rammed tires which received a permit in La Animas County, and designed another for Trinidad, both in Colorado.
I'm also incorporating them in several current designs, not only as earth retainment walls but also as footings, driveway fill and moisture-tolerant sub-grade insulation extensions for annualized geo-solar.
CARDBOARD BALES - Architecture students at Auburn University's Rural Studio have experimented with and built a dwelling of bales of shreaded, wax-impregnated corrugated cardboard from packaging manufacturers. They measured 28" x 78" x 32" high, bound around at 6" intervals, beginning 4" from the bottom, and so far, remain exposed to the weather, although they've been exploring compatible stucco mixes. For more on these and research into their use, try RuralStudio.com (site has changed since original posting of this article) and CorrugatedConstruction.com (site has changed since original posting of this article) or see illustrations of the finished living "pod" in the book, RURAL STUDIO (which is a must-read for serious alternative builders, anyway). They claim thousands of tons of this cardboard go into landfills each week because the content prevents recycling! So building with them seems a far better answer.
PAPERBALES - A related product, are made of waste paperboard like that in soap boxes - see an article in the July/August 2002 issue of Natural Home Magazine about a home Rich Messer and Ann Douden built using these for walls, over similar bales of post-consumer PVC "trash" (on a gravel base) as footings. About 28" wide and 32" high, Rich figured the paperboard provides at least R-30, but with soft wood figured at 1.25 per inch, I suspect they'd test more like R-40. To order a copy of the magazine issue describing their project, contact NaturalHomeMagazine.com.
And finally, "CULM BLOCKS" deserve a brief mention. These are apparently patented, remanufactured bales of rice straw - high-silica, squarer, more uniform, pre-drilled and encased in wire webbing specifically for load-bearing construction. According to a California government fund-granting website: NaturalHomeMagazine.com (dead link), they measure 12" x 16" x 24" and weigh about 60# to 90# each. For up-dates on this prototype product see the company site: Oryzatech.com (site currently under reconstruction).
For the adventurous, I'd recommend giving all these "odd-bales" a look-see. |