[greenbuild] Re: Infill materials for odd spaces where straw won't work
- From: "STEVE PAISLEY" <pppaisley@xxxxxxx>
- To: <greenbuild@xxxxxxxxxxxxx>
- Date: Mon, 16 Sep 2002 22:14:47 -0400
Here are some thoughts on this:
1) For small spaces, like where one bale was shorter than the others or
between a bale and a window buck, you could use hand-stuffed cellulose--just
keep stuffing handfuls of cellulose in until you can't add any more. I
insulated whole house this way once--before I had access to a good cellulose
blowing machine. You can pack it in to a surprising firmness, and it will fill
the entire cavity so as to prevent air convection within the wall. Homosote or
other "board"-type products seem like a bad idea to me because they might leave
open cavities within the wall.
2) For larger spaces, like the triangular spaces in a gable-end wall, you
could do blown-in cellulose behind plastered mesh. Cavities that are not more
than 2 or 3 square feet of wall area can be effectively blown through a 1"
hole, so you could use chicken wire and plaster over all but one little
hexagon, and then blow in your cellulose through that. You'd need to be
careful not to pack it too tight though, or you risk blowing the plaster off
--at high pressure, cellulose blowers have been known to pop sheets of
improperly fastened sheetrock right off the wall. (Don't let this scare you,
though--it's easy enough to adjust the pressure on the machine. Jon Harrod
could probably do this for you, or I think Wickes and 84 Lumber might have
machines.)
3) Straw-clay would work, though I don't know if your inspector or
architect would like it. (If only Georgia-Pacific would start selling straw
bales and clay slip...). I have made some sample mixtures of cellulose + clay
slip which seem promising--they are almost rock-hard when dry and have about
the same density (and presumably a similar R-value) as hardwood. My only
concern would be drying-time. My samples are from 1 to 3 inches thick and took
from several days to several weeks to dry, so I'd be worried about a 16" thick
piece starting to rot before it dried out. The best application for the stuff
is probably as an interior plaster for strawbale walls ( doesn't crack much and
can be made pretty smooth with only one coat) or as a crack-filling alternative
to expanding foam. Ecovillage soil (with the rocks strained out) would
probably be fine for this--I don't think you'd need to bring in clay.
sorry for rambling on like this, --Steve Paisley
----- Original Message -----
From: Joe Nolan
Sent: Sunday, September 15, 2002 3:55 PM
To: Strawbale List
Subject: [greenbuild] Infill materials for odd spaces where straw won't work
Our architect is reluctant to allow any stuffed straw due to fire
resistance concerns (the building inspector specifically asked how we would
ensure a "machine-equivalent compaction rate").
So, I'm trying to come up with some alternate materials for those odd
spaces where modified bales won't work well. The walls are stick framed,
and we'd prefer infill materials with firmness for structural reasons.
Following are some first thoughts. Any experience with these? I still need
to research the properties/costs/availability of these. Any info appreciated.
1) Sheep's wool, treated with boric acid powder (smaller spaces)
2) Homasote board
3) Corkboard
4) Strawboard (core of Agriboard without OSB)
5) Blown cellulose behind plastered mesh
Thanks!
-
Joe Nolan
Ithaca, NY
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