Roofing - Plastic or Tar Paper?April 30th 2003
While gathering information on replacing my asphalt shingles, I was told that to meet current city code, I must lay down a sheet of plastic poly on the roof decking then install the shingles. I had just read your response to a letter which advised against the use of plastic. I drove into the new construction area and there was a lot of roofers installing shingles over clear plastic poly. Why would there been two different opinions on this installation?
Different building areas and codes call for poly or tarpaper, they both serve the same purpose. They stop airflow through plywood or OSB joints and direct air to the ridge or roof vents as well as to the soffits. My preference is tarpaper for breathing reasons but hey, you can't argue with local building codes.
It's Just That Easy!