Expert: Dave Johnson - 6/3/2009

Question
Sir,

We are having to replace the sheetrock from our home and I am trying to determine what to do about the insulation in the exterior walls.

The code here requires only the Fi-Foil (foilbacked craft paper) which I have been told it is actually the same r value as the 1" insulation board.

Are thsee really the same efficiency rating? I would think the foam board would be a much superior insulating product.

Bottom line I am being told by the supplier that its a waste of money to use the foam board? What is your opinion?

Thanks in advance

Answer
Hi Robert,
Since you are going to have your walls open anyway, if the existing insulation is in good condition, I would add a foil faced rigid foam board over the stud faces before replacing the drywall.
The code indicates to me that you are in the south. If this is true
you may not want to go the route above, but it costs a lot to cool a  home these days, too....
Anyway, mail me again if this is not clear... And best of luck!

Dave