m Ransley wrote:
You won`t get R4 per 1/2" out of any board I know of, R7.2" new and
stabilised at R6+" is the best Polyisosyanurate gets. I covered my
house in 2" polyiso for R 14.4. Can you replace siding on a soft surface
and not over nail it making it uneven? I covered mine in Osb.


1/2" Dow blue foam board is R3 and that is the best I could find when I
searched for materials for my basement remodel. Perhaps one of the
foil-faced types might do better but I don't recall any.

--
John McGaw
[Knoxville, TN, USA]
http://johnmcgaw.com