Posted: Sat Apr 03, 2004 12:39 am
I'm not sure if I've ever seen the green board used in that way - it's intended for wet areas such as bathrooms. Kase, you work with this stuff every day, any comments? IF not, maybe Rod Gervais has the answer. I don't see why it wouldn't work, but that's got nothing to do with code...
Kase is right - if you can't find Tyvek (not likely, actually) the 15 pound felt is another, older method that works. Do NOT, repeat NOT, use poly or any other totally water PROOF layer there, it needs to be able to breathe and dry out when moisture gets through the outer siding (and it WILL)
Come to think of it, I doubt if the greenboard drywall would be acceptable to code, and with good reason - there is a property of framed walls referred to as "racking resistance" - it means the wall's resistance to skewing out of shape along the length of the wall - picture a row of dominoes, set up as if they were wall studs - you tip one over, they all go - but if you put something on one side of them that has a lot of resistance to that sort of movement, they won't tilt at all.
Same thing with wall construction - you need that "racking" strength, which drywall won't provide. And by putting a layer of drywall under the outer siding, you move that siding further from the studs, making the nails work harder to keep things from sliding sideways. (The nails would just pull through the gypsum with excessive side force) For that reason, I'd be surprised if any type of gypsum wallboard would be accepted for that use... Steve
Kase is right - if you can't find Tyvek (not likely, actually) the 15 pound felt is another, older method that works. Do NOT, repeat NOT, use poly or any other totally water PROOF layer there, it needs to be able to breathe and dry out when moisture gets through the outer siding (and it WILL)
Come to think of it, I doubt if the greenboard drywall would be acceptable to code, and with good reason - there is a property of framed walls referred to as "racking resistance" - it means the wall's resistance to skewing out of shape along the length of the wall - picture a row of dominoes, set up as if they were wall studs - you tip one over, they all go - but if you put something on one side of them that has a lot of resistance to that sort of movement, they won't tilt at all.
Same thing with wall construction - you need that "racking" strength, which drywall won't provide. And by putting a layer of drywall under the outer siding, you move that siding further from the studs, making the nails work harder to keep things from sliding sideways. (The nails would just pull through the gypsum with excessive side force) For that reason, I'd be surprised if any type of gypsum wallboard would be accepted for that use... Steve