Synthetic vs. Felt Roofing Underlayment: Which Is Better?

Choosing the correct underlayment for your roof replacement project is crucial to ensuring your home’s protection against the elements and for the actual roof’s long-term integrity. Two popular options that come to mind are synthetic and felt underlayment, each with its unique benefits and drawbacks. Local roof repair and replacement contractor BSR discusses them below.

What Is a Roofing Underlayment?

The roofing underlayment is a layer of material placed between the roof deck and the shingles. It is a secondary barrier that protects the roof from water intrusion, enhances durability, and provides additional insulation. Given the fluctuating weather conditions, a dependable underlayment is indispensable for long-term protection and efficacy.

Synthetic Underlayment: The Modern, Durable Choice

Synthetic underlayment, a product of technological innovation, is crafted from woven or spun polyethylene or polypropylene. It is renowned for its strength, tear resistance, and longevity. Synthetic materials are typically lighter and more slip-resistant, making them safer for installers.

Furthermore, synthetic underlayment generally exhibits higher water resistance and can withstand exposure to the elements for extended periods. This quality is particularly beneficial in the event of unexpected weather changes during a new roof installation or roof repair. Homes in areas that may experience varied weather can benefit significantly from this type of underlayment.

Felt Underlayment: The Traditional, Time-Tested Option

Felt underlayment, also known as tar paper or felt paper, comes in two grades: #15 and #30. This type of underlayment has been relied upon for decades due to its availability and cost-effectiveness. Although heavier and less durable than synthetic variants, felt underlayment provides reasonable water resistance and is an adequate barrier against the elements.

The key advantage of felt underlayment is its affordability, making it an attractive option for homeowners on a budget. It’s also more familiar to some older, experienced contractors and is readily available in the local market

Performance During Installation and in the Long-Term

It’s worth noting that the performance of underlayment may vary during installation. Synthetic underlayment is prized for its robustness, ensuring fewer tears and repairs, making it a solid choice for roofing. However, during colder temperatures, felt underlayment can become more brittle and challenging to work with, potentially leading to increased installation costs.

Over time, synthetic underlayments are less likely to degrade under UV exposure and extreme temperatures, contributing to a longer lifespan of the roofing system. However, felt may absorb moisture, leading to wrinkling, which can affect the lay of the shingles and potentially reduce its effectiveness as an underlayment.

Environmental and Safety Considerations

In environmental terms, synthetic underlayment may offer benefits due to its lighter weight, which potentially reduces transportation emissions. It is also less prone to mold and rot, providing a healthier living environment. Safety-wise, the slip-resistant nature of synthetic products is a critical factor for installers.

Choosing the Right Underlayment for Your Home

Selecting between synthetic and felt underlayment will heavily depend on your budget, the climate in your region, and long-term performance expectations. For specialized advice tailored to unique climatic needs and personal circumstances, seeking the expertise of a local contractor is imperative.

For top-notch home exterior services, turn to BSR. Call us at (607) 678-3611, or complete our contact form to schedule a consultation. We serve clients in Binghamton and Vestal, NY, and the surrounding areas.