WHY ROOFING FELT IS IMPORTANT
Roofing Felt. Think of it as your roofing deck’s bodyguard. Roofing felt is important because it acts as a barrier- a line of defense-between your roofing deck and the elements. If you’ve ever passed by a roofing project, you surely noticed the black paper sheet on the roof before the shingles are applied. This protective barrier is known as roof underlayment. Roofing felt is one type of roofing underlayment and it extends the life of your roof by protecting it from water, fire, and severe weather. Many building codes and professional organizations, such as the National Roofing Contractors Association (NRCA) strongly recommend the use of roofing underlayment for every project. Not only is roofing felt important for the protection of your home, but it also adds to the aesthetics, ensuring a uniform look. Let’s look at some of the benefits of roofing felt.
BENEFITS OF ROOFING FELT
ACTS AS A WATER REPELLANT
Nature’s elements can wreak havoc on your roof. Roofing felt is important because it repels water preventing moisture from getting trapped between shingles and roofing deck wood. Moisture damage is detrimental to your roof because it causes leaks, water damage and mold. The layer of paper felt helps the water drain off your roof and prevents leaks into your home.
PROTECTS ROOF DECK DURING INSTALLATION
Many times, it takes a while for the roof to be complete. During the installation process, roofing felt protects the wood until the shingles can be applied.
KEEPS SHINGLES UNIFORM
Roof decks are not always straight. Roof felt is important when it comes to keeping the surface uniform prior to applying the shingles. This prevents bumps and imperfections which can not only compromise the roof, but creates a “picture framing” effect, or the pattern of your decking showing abnormalities through the shingles.
PROTECTS AGAINST SNOW AND ICE
Snow and ice are especially hard on a roof. When piles of snow accumulate on the roof and then quickly melt, water may leak through the crevices of your roof. The extra protection that paper felt provides helps to protect insulation, ceilings, and walls from the water that pools on your roof.
FIRE PROTECTION
Roofing felt has a Class A Fire Rating which means that it can withstand fires. Shingles alone may not meet the Class A Fire Requirements. ASTM International or Canadian Standards Association (CSA) on the product label means that the felt is compliant and often comply with building codes.
LOWERS HOMEOWNER’S INSURANCE RATES
Because of roofing felt’s Class, A Fire Rating insurance rates are typically lower for homes that have use roofing felt.
PREVENTS WOOD RESIN STAINS
Specific types of wood may leach resin over time. Roof felt’s protective barrier prevents this resin from staining your shingles.
WHAT IS PAPER FELT
As we stated, roofing underlayment lies between the roof deck and the shingles. There are two types of roofing underlayment, synthetic and paper felt. Paper felt is one of the oldest types of underlayment and has been used for decades. Over a hundred years ago when the manufacturing of paper felt began, cloth felt from recycled cotton was used to make asphalt felt. Today, paper felt is made from saturating paper or sawdust and recycled paper with asphalt. Paper felt costs less than synthetic underlayment and comes in two different types: No. 15 felt, and No. 30 felt. No. 15 felt weighs between seven and fourteen pounds per 100 square feet. No. 30 felt weighs 16.5 or 17 pounds. The ASTM D 4869 requires No. 15 felt to weigh at least 8 pounds per 100 square feet. ASTM D226 is a stricter standard, requiring a minimum of 11.5 pounds per square. If you have a steep pitch roof, use No. 30 felt, however if your roof is not steep, No. 15 will suffice. No. 15 paper felt is a more economical choice, however, it is not as thick as No. 30 paper felt. Overall No. 15 felt paper, is thicker, tears less during installation and offers better protection.
There are pros and cons to all roofing underlayment. When choosing the best underlayment for your roof, consider your geographic location, the weather in your area, your roof’s design, what roofing materials are being used, and your budget. Talk with your roofing contractor to determine the best option for your roof.