On 6 Dec 2005 07:03:21 -0800, wrote:

Use the washers as above. When I did this I also went over the studs
with 2" polystyrene. This gave twice the R value but if you do this
make sure to mark the stud location carefully for wallboarding.
Richard

Since he's got plywood behing the foam, he doesn't need to worry
about finding a stud. just put glue on the foam and smash it
against the wall, pull it off and let it cure per the directions,
put it back against the wall, and screw the sheetrock on. The
sheetrock should work fine as a "washer".