"KLS" wrote in message
...
On Thu, 1 Nov 2007 19:43:24 -0700, "Bob F"
wrote:
wrote in message
...
I want to upgrade my attic insulation. I have 2x6 beams and old
unfaced R13-R19 fiberglass batts up there. I want to add R38 on top of
the existing insulation. I am in San Jose, CA.
[cut]
I went for the batts. It is great to be able to move them aside to add a wire
or
whatever. I did it myself. It probably took 3-4 hours.

As far as insulation value, if you place them carefully together, fiberglass
should be fine. And it doesn't settle over time like the blown in cellulose I
put in my previous house.

Why aren't you considering icynene or polyurethane for maximum
insulation?

Because it would cost way more for the same insulation level, It's difficult to
install also. Foams only make sense for me if there is not space enough for
conventional insulations. Also, it would make re-working things in the space
very difficult.

Bob