M. C. writes from Albany, New York: "I'm un-doing a bad 1960s reno of the kitchen in our 1890s brownstone in upstate NY. I want to insulate the back exterior wall, but it's shallow and I'm wondering how best to proceed. The depth I have to work with is only about one inch, as I plan to sheetrock directly to the original furring strips that are attached to the brick. I don't want to build the wall out for reasons of space, and because I want to stay at the original depth of the door and window frames. Questions: Would roll insulation work, or would it lose its value from being too compressed? I'm thinking of rigid foam board, but I'm wondering if it has enough insulating value to make a difference. And, finally, what about a vapor barrier before I close the wall back up? (As an aside, I'm retaining the original wooden wainscoting over plaster along the bottom of the wall and won't be able to insulate that portion. I want to make some difference but realize my situation in working with an old house is not ideal.)"

Answer: Since you don't want to build out, foam is about the only option we can think of for your situation. One inch of extruded PINK foam insulation (R-5) is certainly better than nothing. I would use foam if I were in the same situation.