Question: Do I need a 6 mil vapor retarder when insulating exterior walls?
Sal writes from Holmdel, New Jersey: "I am renovating a 15 x 15 room with two exterior walls. Of course I am going to insulate but do I need a 6 mil vapor barrier also?"
Answer: What is the building code in New Jersey calling for? Personally, I think a 4 mil or Kraft vapor retarder will do. A 6 mil vapor retarder is very strong but would not cause a problem.
