Steve writes from Shrewsbury, Massachusetts: 'Can I apply rigid closed-cell foam board over existing wood clapboard siding? The exterior 2x4 wall is fiberglass insulated, sheathed with plywood (not OSB), wrapped with a vapor barrier, and finished with cedar clapboard. Rather than repair & paint, I was looking at vinyl and figured I'd add as much insulation beneath the vinyl as possible. I don't mind building out the exterior finish of windows/doors, so adding more than one rigid layer is what I had in mind - think 'super insulation'. (I am familiar with homes having double windows - that is, two windows between the interior and exterior space - so building-out to that extent wouldn't be new to me, but not my first choice.) So, if I can just apply the board over the siding, additional questions include: how may layers, fasteners, and other envelope information like insect issues, etc.?'

Answer: Yes. This is an expected and acceptable application for PINK FOAMULAR® 150 or 250 insulation.