Jeff writes again from Mansfield, Massachusetts: "Thanks for your help with the previous question. It worked out well. I have a house built in the early 70s. We are going to re-side it with vinyl siding. It has 2 X 4 wood framed exterior walls with rigid foam insulation between stud bays. I doubt if the walls are even R-11. I'd like to increase the R-value of the walls by removing the existing vinyl, apply rigid insulation to the plywood sheathing, wrap the house with a house wrap material, and then reside with vinyl. My questions are about products, fasteners, and application process, and how to create the most R-value (remember, I live in MA (02048) where the winter is 8 months long):

• What insulation should I use and what thickness?
• How do you fasten the insulation to the existing plywood siding? How do you fasten up the siding over the insulation?
• How thick can the insulation be and still find a fastener for the siding that will penetrate deep enough that it will hold the siding on?
• What house wrap, or are they all the same?
• Is it possible to seal the house up too tight?
• Do you have anything I could read about this?"

Thanks for writing, Jeff. You are the first reader to send a second question -- or in your case, a second list of questions. Here we go:

• Any of the Owens Corning PINK FOAMULAR products can be used. I recommend 1 inch thick, provided you can accommodate the space.
• Plastic cap nails of the appropriate thickness can be used to attach the foam.
• The siding is fastened as it would be with new construction, just use longer nails.
• I have seen siding/roofing nails as long as 3 inches so you shouldn't have any trouble using even thicker than 1 inch foam.
• If you choose to use housewrap, I naturally recommend Owens Corning PINKWRAP housewrap. But housewrap really isn't needed if you tape the seams of the foam. In that case I recommend PINK Bild-R-Tape Construction Tape.
• Not really. You want a house to breath, but you want to control how it breaths through the HVAC system.
• The Energy Star Website has information you can read about home sealing.