Many roofing contractors will tell you that the purpose of roofing felt or underlayment is temporary waterproofing to “dry-in” the structure before the roof shingles are installed. They identify that any secondary waterproofing the roofing felt or underlayment provides is entirely negated by the numbers of nails pushed through it. This makes some sense when you realize that roofing felt or underlayment is nailed or stapled, and then a typical architectural shingle roof takes ~800 nails for every 100 square feet of roofing area. If you use a high-wind nailing pattern, that roofing felt has ~1,200 nails for every 100 square feet of roofing area. That is a lot of “holes” in something that provides secondary waterproofing is what these contractors will tell you. They will tell you that you can get by with no felt at all, or at a maximum they will install a 15-lb. felt.
If you read any asphalt roof manufacturer’s warranty literature or installation criteria, you will note that universally they specify minimum underlayment requirements. Vary from this installation procedure, and the warranty isn’t valid. Those contractors that tell you roofing felt or underlayment isn’t necessary will also maintain that of course any company that manufactures and sells roofing materials wants to sell you more product, and they also manufacture and sell roofing underlayment that they specify for installation.
The roofing contractors that tell you this tend to be low bidders, and are often high-pressure storm-chasers that descend on areas after hail storms or other wind events that cause widespread roofing damage. A 30-lb roofing felt costs about $7 for every 100 square feet and 15-lb roofing felt costs about $3.50 for every 100 square feet. In comparison, architectural shingles are about $100 for every 100 square feet, so this savings amounts to mere pennies on a replacement roof. As your home is likely your most valuable asset, do you really want these contractors working on this when you know they are cutting corners that required by the manufacturers that make and offer warranties on their roofing materials? That sounds penny wise and pound foolish to me. Find a local roofing contractor who has been in business in your locale and has a proven reputation.
We are an experienced Lees Summit roofing company with over 15 years experience in repair, service and installation.