The house was built in 1939 and has wood shake on the exterior. Pulling off a couple of layers revealed wood sheathing with a 2″ round plug. Behind the plug was a white material that 2 out of 3 local (SLC) insulation contractors say is a polyiso foam; the other contractor said it was a blown-in fiberglas. The retro insulation work was done prior to 1987.
Anyone have a definitive answer on what this insulation is and it’s R-value?
Also, any suggestions on the “best” way to increase the wall to R-19, per Energy Star recommendations for Salt Lake City, including any vapor-barrier issues?
Thanks,
— Rick Gregory
Replies
I don't think it is either.
Chopped FG is just like cotton to handle. Not hard to recognize or pull some out
Polyiso looks similar to what they used back then, a slightly different foam that was not nearly as good. It was pumped in through 1-1/2" or 2" holes, and slowly expande to cure, but it often shrank back from studs and down from top plate, leaving voids that would telegraph by letting condensation form on interior walls in patterns reflective of the shape it shrank too. It had wicked amounts of Formaldehyde in the formula, that sometimes still gives off a weird odor when disturbed.
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
Perhaps this stuff really is chopped FG.It is soft to the touch. Looking at a sample under a microscope revealed a mix of fibers and tranlucent scale-like pieces.If it is FG, do you know what the R-value that a blow-in installation usually achieved? And does it have the problem you describe with the old foam of pulling away from the studs/walls?Thanks,-- Rick Gregory
[email protected]
Would probably not hve the shrinkage problem.What you are describing sounds lik eiot might have beena wet applied type with glues - though I have never heard of that with FG, only cellulose.Dry modern BIBBs FG is about R-3.5 per inch of thickness in a dens situation such as stud spaces
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!