mfreak wrote in news:67ec1379-70a0-4864-827b-
:
I think your weight concerns will work out Ok. Structural calculations use
design loads of 25 to 50 lb/sq ft and all you are adding is 2 lb/sq ft.
This is well within allowances.

The foamed in place stuff would absorb quite a bit of sound but since the
mass is low it would not absorb a lot more than other things. It costs
around $1.25 a board-foot so 10 inches would be $10/sq ft - sounds like too
much to me. I think you would get good benefit for only 4 inches thickness
- $4 to $5 a sq ft. The foamed in place stuff adds structural strength so
it may be a wash, especially if you foam all the way out to the supports.