[Greenbuilding] [BULK] Re: Mold questions

[Chris Green]

Lawrence Lile wrote:
> In addition, I have understood that the foil faced insulations, which start out at a really high R value, end up outgassing the blowing agent and then losing
> R value over the years.  All foams have this problem, but the
> polyisosyanurate has the problem to a greater degree.  This comes from a
> contractor, I don't have a reference for any reasearch on this.
I've recently heard this too. In fact, the buyer of the house I'm 
working on mentioned it. And he's an insulation contractor. I think that 
we are using the styrofoam and foil Insulboard because it has the foil 
and reflects the heat back into the house and wall cavities. I assume 
this will help create a warmer and drier stud cavity, but since this is 
a desert area (about 5" of precip  a year) the type of moisture problems 
found in, say, Oregon and the Olympic Peninsula/ Puget Sound area aren't 
a problem.
> The manufacturer of Extruded foam board recommends a 1/4" gap between
> boards for expansion and moisture movement, with no tape cover. 
I wasn't aware of that. Thanks for mentioning it. I'll scratch the 
taping idea off the list of notions... :-)

Cheers,

Chris Green.