willshak wrote in
:

on 8/26/2007 8:46 PM DerbyDad03 said the following:
I'm going to be replacing my windows soon. I plan to use minimal
expanding foam to fill the gaps.

The Great Stuff for windows (blue can, "Will not bow frames") says
uncured foam can be removed with acetone. Can I assume that the
acetone will not harm the vinyl?

I've been practicing trying to neatly fill a 1/8" gap with the
supplied straw and it's pretty tough, even after pinching the straw so
it will fit into the gap.

Do I need to put foam in a 1/8" (or smaller) gap?

(This is the side gap I expect since I'm told my windows will be 1/4"
narrower than the rough opening.)

Thanks!


In my short career as a house builder, all the gaps between rough
opening framing and the window or door framing was done with pieces of
glass wool insulation stuffed in with a putty knife. It is not the
material that provides insulation, but the air trapped within it.



...stuffed in with a putty knife.

...but the air trapped within it.

I would never disagree the trapped air is the insulator. But I really
have often wondered when the gap is so small and they are forced to
"stuff" it in what good is it?!

I just installed two Anderson windows in the very-northeast. See what
happens this winter.

On the sides and head I filled the gaps with low expanding foam.
Anderson's installation instructions gave this as an option. In the sill
I sealed with a bead of foam way in where the sill meets the RO then used
fiberglass to fill the large void. I figured the bead would eliminate any
air infiltration from minute openings and the glass would give it some R
value since it could easily be packed loosely. All the fins on the
outside were siliconed to the sheathing and covered with flashing tape.

If they are drafty or leak, I dunno what else I could have done.


Al Bundy,
Professional (wanna-be)