Replacing a roof is one of the largest home investments people make and it comes with a variety of choices. When reviewing estimates or bids from roofing contractors, you may see options for different types of underlayment.
What is Roofing Underlayment?
Underlayment refers to the layer laid between the shingles and the roof deck. This extra layer provides added protection against rain, snow, and wind. Until recently, there was only one option for underlayment and that was a cloth-like material called “felt” or “tar paper.” Around 20 years ago, “synthetic” underlayment was introduced to the roofing industry.
What is Synthetic Underlayment?
Synthetic underlayment is made of a lightweight, highly durable, plastic-like material. More importantly, it provides a superior level of protection from weather elements. Synthetic underlayment material is water resistant and helps prevent mold growth. In the event of storm damage where shingles are damaged or blown off, it will help protect a home from water until roof repairs are made.
There are a variety of synthetic underlayment options available from different roofing material manufacturers. An expert roofer can explain these different options. In addition, they can offer recommendations that take into consideration the roofing system being installed, repaired, or replaced.
The other roofing underlayment option is felt. For nearly 200 years, felt was the only underlayment material used. It is cheap and provides an extra layer of protection. However, it absorbs water rather than repelling it. While absorbing water helps prevent it from entering a house…there is a limit to how much water a felt underlayment layer can absorb.
The fabric-like material is heavier than synthetic and much more delicate. As a result, it can tear easily and will not last as long as synthetic options. Felt underlayment can typically be purchased at two levels: No 15 and No. 30. Felt No. 30 is stronger and thicker and can withstand more exposure than No. 15.
Synthetic vs. Felt
Felt is less expensive than synthetic. However, it may not be worth the savings. Synthetic underlayment is more durable then felt and offers better protection from the elements. It is a lighter weight material which translates into less stress on a roof deck. Additionally, synthetic underlayment is faster and safer for roofers to install which can lead to savings in labor costs.
Felt underlayment may be the best solution given one’s budget. However, roofing systems with synthetic underlayment offer superior protection, require fewer repairs, and last longer.