When it comes to roofing felt (A.K.A. tar paper, or underlayment), there is a lot of confusion and misinformation out there. So we wanted to take this opportunity to provide you with the facts, not the sales pitch.
The Origins of Roofing Felt
Roofing felt has been around for over a hundred years. It was originally designed as a means to temporarily waterproof a roof after the shingles were removed. Back before roofing contractors were so prevalent, many homeowners were forced to perform this backbreaking work themselves. Roofing felt allowed more flexibility in the re-roofing process, making it possible for a small group of friends or family to remove the roof one weekend, install Roofing Felt (keeping the home dry during the week) and then install new shingles the next weekend.
It wasn’t until shingle manufacturers started producing their own brands of Roofing Felt, and looking for ways to improve their sales, that it was marketed as an “essential component” to their system. Since then, manufacturers have made improvements to the basic materials used, increasing the benefits of using felt.
What are the benefits of Roofing Felt?
- Temporarily dries in a roof
- Reduces likelihood of workers slipping, creating a safer work environment
- May increase the fire rating of the roof system
- Moisture barrier between wood decking and shingles
No one argues the benefits of felt, but sometimes overreaching salespeople make claims that simply do not hold water in an attempt to convince a client to spend more money on a “felt upgrade”. It is important to realize that once the shingles are properly installed, thousands of nails penetrate the Roofing Felt, essentially ruining it – no matter how thick it may be. If a leak develops after the shingles are installed, the felt will not serve as a long term means of preventing it from entering the attic.
Yet, most contractors install it and most building codes require it for the reasons stated above. When used and marketed as the product was intended, installing roofing felt makes sense.
Why Use a Thicker Felt?
Although standard #15 felt is the most common temporary dry-in product, there are occasions that justify a thicker felt, such as #30. The most frequent is a result of a steep pitch; the thicker felt resists tearing, making conditions safer for the installers. However, thicker felt does not increase water resistance.
Felt is a temporary dry-in product and not designed to resist continued water exposure. It creates a safer surface for workers to walk on.
These are benefits for the Contractor.
A thorough search of today’s top manufacturers for information on their felt warranties can result in frustration. It quickly becomes evident that although they are heavily pushing their felt product as an “essential part” of their roof system, they provide little to no information on their actual felt warranty. Some go so far as to state “individual components take on the warranty of the shingles installed on the field of the roof.” The real means of waterproofing are the shingles themselves.
Although some counties and regional building codes have added certain felt requirements, most of the manufacturers themselves give no specific warranty coverage on their felt products.
Waterproofing Membranes (Ice & Water Shield)
In Georgia where “dead valleys” and slopes of 3/12 and less are common, specific waterproofing membranes may be required. This product is not felt. It is specifically designed to seal around the penetrating fasteners and act as a last defense against water penetration. Ice & Water Shield was developed primarily for Northern climates that suffer from Ice Damming but also to help minimize wind driven rain on low sloped roofing. In Southern, warmer climates it is often used as an alternative to metal as a valley liner.
Sparrow Exteriors understands that not all roofs are identical and that each requires a customized installation. We believe in providing you with the ideal roofing system for you and your home and/or business. If you have questions regarding felt or other forms of underlayment, please feel free to call us for more information.
Sparrow Exteriors specializes in roof replacement, roof repair, gutter installation, attic insulation, painting and siding; servicing the Greater Atlanta area and is proud to be a Georgia company. Whether you’re considering a home improvement, or you believe your home may have suffered hail and wind damage, call us for a Free, No Obligation Inspection!