|EnerGrid/ Rastra block construction material||<– Date –> <– Thread –>|
|From: Lynn Nadeau (welcomeolympus.net)|
|Date: Sat, 19 Jan 2002 13:10:01 -0700 (MST)|
>Lynn, what are EnerGrid blocks and what do they have to do with being in >Washington State? > >--Diane > Jamaica Plain Cohousing, Boston, Massachusetts > >- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - >>We used EnerGrid blocks, which probably raised the construction cost, >>>compared to stick framing. We're in Washington State. That we are in Washington State is an unrelated fact (one Stephanie wanted in the psf costs). EnerGrid, also known as Rastra Block, is a wall-construction material made of concrete and ground-up recycled styrofoam. It comes in long bars, a bit like giant cinder blocks or Legos. The bars have holes cut at intervals, so when you stack up a wall, you have vertical hollow channels. Steel rebar rods are placed upright in these channels, and concrete is poured around them, creating reinforced concrete "pillars" at intervals in the walls. The block material itself is slightly crumbly, and can be cut with a saw, knife or other carving tool, which can lend itself to creative trim details, and also allows blocks to be cut to size. The wall has its insulation in the material itself, like strawbale construction, unlike standard wooden construction which has an inner and an outer layer, with insulative filling of fiberglass, cellusose or whatever inserted in between. ADVANTAGES and DISADVANTAGES + saves trees - indoor framing is still wood + uses concrete, which some say is environmentally good - uses concrete, which has a high energy cost in making the cement - blocks we used had to be trucked from Mexico (with fossil fuels); I think it now has to be trucked from the Southwest somewhere. - because of that, you also can't just run to the lumber yard for some more + is well suited for owner-builders, especially if you have some afficionados of the material who will organize the team effort in a knowledgeable way + if you have local interest, you can get volunteers who will help, as a way of gaining experience with the techniques - regular contractors have no experience with it + high insulation value - wall insulation less important than roof insulation, and if you have walls full of glass windows and doors, they defeat the goal of avoiding heat loss + allows creative detailing + logical exterior finish is stucco, which is very low maintenance into the future + stucco is expensive, unless done by volunteers (we did volunteers, with a few paid leaders) + logical interior finish is Structolite plaster, which is amenable to shaping, arches, and creates a somewhat hand-made-looking finish, with interesting texture. - Structolited walls are vulnerable to chipping and cracking when you want to nail or screw things into them, but it can be done - Structolited walls are not truly flat, which makes it hard to get cabinetry or such flush. - attaching things to Rastra walls required special masonry anchors, or foresight in installing wooden blocking in strategic locations, before plastering. - electrical and plumbing in the walls requires pre-planning, with channels left open or routed out; later additions are less simple than in stud walls + the material is fireproof - it costs as much or more than wood framing in an area where construction wood is readily available Some people think this is a super-environmentally-sensible material. Obviously, my support is more qualified. Given our particular circumstances, it worked well. (Members in the construction trades who love working with it and converting others to their passion; lots of interest in detailing; others in town who wanted to volunteer and learn; volunteers for stucco and plaster work. ) We also have two houses at RoseWind built of Rastra. The local Unitarian congregation had recently built their church and parish hall using Rastra and nearly-all volunteer labor, and we had the same contractor coordinate our project. One of the RoseWind houses is shown in the recent coffee-table book, The New Cottage Home, by Jim Tolpin. The stucco was left gray, and ground up oyster shells were thrown at it while it was wet, creating a finish my sister says in Georgia is called "tabby". That book also shows how they carved fake-stone trim for the corners of the cottage. Hope that helps. There must be a web site, but I don't know which. Lynn Nadeau, RoseWind Cohousing Port Townsend Washington (Victorian seaport, music, art, nature) http://www.rosewind.org http://www.ptguide.com _______________________________________________ Cohousing-L mailing list Cohousing-L [at] cohousing.org Unsubscribe and other info: http://www.communityforum.net/mailman/listinfo/cohousing-l
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