Roofing felt?

Question:Recently I just tore off the old house roof down to the bare wood and starting to apply felt paper. I applied 30 pound felt to the side that I tore off. However, I am going to use 15 pound felt for the other half of the house. Is there a problem with this or will the shingles and roof not look or perform any different from eachother? Thanks.

Answers:
jason b
Want to know why some roofers don't like to install felt? Because modern shingles are thin. Any wrinkle in the felt will telegraph through. A professional can install felt so wrinkles aren't a problem. For others it's a time consuming process to be avoided. If budget is not a critical issue, be sure to stipulate the more expensive wrinkle-free felt supplied by GAF or Certainteed. Thirty Pound felt attached with simplex nails is acceptable for use with Architectural Shingles ONLY. Thirty Pound felt under light weight shingles may lead to telegraphing of the plywood through the shingles. Fifteen Pound felt is standard and is acceptable for all shingles.

Why use felt?
ALL roofing manufacturers for the following reasons recommend roofing felt:

· Felt is an integral part of the system that protects your home from condensation.

· Without felt your roofing system does not qualify for a UL Approved Class A Fire Rating.

· Felt provides a slip shield or buffer between your shingles and the deck of your roof.

· And in the old days, felt protected organic shingles from pitch that leaked out of knots in the wood. Fiberglass shingles still have organic petrochemicals. In my opinion, the shingles still need to be protected.