On Wed, Feb 22, 2012 at 9:15 AM, Karl Vacek <kvacek@ameritech.net> wrote:
> OK - I'll be careful about the canned foam over-expanding. B I've seen
> low-expansion stuff in cans at Menards or somewhere, so I'll try for some
of
> that. B However, I tried some low-expansion latex foam 6-7 years ago and it
> was pretty useless (DAP or some known brand as I recall). B This is a very
> small project, and I'd only use about 1/3 of one of the real home-foaming
> kits, so that's not really an option.
Have you talked to a contractor? construction is still slow. You
might get someone willing to do a small job. They use a two part
system, so there's reason they can't do it.
>
> In any event, what I'm doing is very small volumes, open all along one
side,
> and I won't be going into closed areas except on top, where it can expand
up
> and all I intend to do is shoot enough to seal it off (balloon frame
house).
> Most of this is spaces a couple of inches wide and a couple of feet long,
> between real 2" x 4" rough-sawn timbers with actual 1" board sheathing on
> the outside, and open to the interior (from where I'll spray it), so I
don't
> expect lots of problems with expansion other than having to cut off the
> excess on the inside.
>
> More to my main concern (which I never really stated), is whether it's at
> all advisable to first try to line the areas with Tyvek house wrap or
> similar, or just foam directly into the little spaces. B Or at least on the
> several wider spaces where I can use fiberglass batts, should I try to line
> those areas with Tyvek in the cavity first, before installing the
> fiberglass? B Seems like it'd cut the wind a bit and give the fiberglass a
> chance to work. B There's building paper on the outside under the wood
> siding, but I found large voids around the windows where I've pulled off
the
> trim. B And pulling the siding on the whole front of the (freshly-painted)
> house to wrap it properly is just not going to happen.
If you're going to spray foam, why are you using fiberglass? Foam is
about twice the R value of fiberglass, and it will certainly stop air
infiltration as well as tyvex does. Fully foamed buildings often
omit any other vapor barrier.
--
David Scheidt
dmscheidt@gmail.com
_______________________________________________
Shop-talk@autox.team.net
Donate: http://www.team.net/donate.html
Suggested annual donation $12.96
Archive: http://www.team.net/archive
Forums: http://www.team.net/forums
|