Una wrote:
Under the very old asphalt shingles on my house is 2 layers of 1/2
inch sheet board, marked "Weyerhaeuser" "insulation sheathing board"
"1B" "R1.92"

Victoria Heisner wrote:
I'm guessing that the old stuff has an R value of 1.92.

You think? :-)

Well, the job is finished. The old inch of fiber board is gone. On
the whole it was in very good condition but in some areas it was mush.
The T&G under the fiber board was in very good condition throughout.
Whew!

Thanks for the feedback, all!

Una