[Greenbuilding] [BULK] Re: thermal bridging--letting it go

[Lawrence Lile]

1. What's a chiroquero?
 
2.  I've run 1 1/2" foam on the outside of a remodel successfully, wrapping each window with a 2X2 ripped to the thickness of the foam.  An omnipotent, all-seeing God also makes 3-1/2" galvanized deck screws, which were required to hit anything through this thick mess, since it went over existing siding and had siding on top of it. Tyvek went on the outside, and was caulked to the edge of the 2X2's at the windows, under the final siding.  I didn't see it as a tough job in the least. 
 
3. In new construction, running 1" foam on the outside is not too hard at all.  The Tyvek can go on the outside of the foam, windows pop in on the outside, standard waterproofing details can be used
 
4. Anything thicker than 1-1/2" foam runs into fastener problems, since God never intended people to fasten siding with 4" screws.  I decided that diminishing returns started to kick in after 1" foam thickness.  

________________________________

From: greenbuilding-bounces at listserv.repp.org on behalf of Alan Abrams
Sent: Wed 12/27/2006 6:40 AM
To: greenbuilding at listserv.repp.org
Subject: [BULK] Re: [Greenbuilding] thermal bridging--letting it go




>implying that the foam sheathing or other t-break should be close to the
>inner surface, rather than the exterior.
>
>This approach resolves numerous problems with foam on the exterior of a
>frame wall--playing havoc with fastening siding, flashing windows, sealing
>at the base of the wall, dithering over whether it goes over or under the
>tyvek, etc.

<how would you attach the sheetrock?>

Oh yes, you would p!$$ off the chiroqueros.  I would of course reply, that's
why a merciful, just, and omnipotent god created 3" drywall screws. 

Or maybe, how 'bout let's stand the boards up, like in commercial
construction, and trap them with baseboard, crown, and chair rail.  For the
faint of heart, run horizontal bands of 2x2's on 25 1/2" centers, with 2'
wide swathes of 1 1/2" foam in between.

The greater issue being that it's less risky to deal with unconventional,
arguably wobbly methods on the cosmetic side of the wall, rather than on the
business side, that has to resist the wind and rain.

Alan Abrams



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