What Is Roof Underlayment?

Roofing underlayment is a substance typically produced from felt, synthetic fibers, or both. As the second line of defense for your attic and home, roof underlayment is rolled over the plywood of your deck after your roof decking has been installed.

Underlayment is obviously not intended to be a stand-alone roofing material, but it is a fantastic weather barrier for your roof decking. Consider it your roof's second line of protection.

Roofing underlayment serves as a waterproofing barrier in the event that inclement weather damages or removes some of your shingles. While you figure out the specifics of the repairs, it protects your decking.

Roof underlayment

Feltexposed roofing felt with asphalt saturation

Felt roofing underlayment, sometimes referred to as tar paper or felt paper, is one of the most traditional and widely used kinds of underlayment in the United States. It normally comes in No. 15 or No. 30 and is produced by soaking a roll of fiberglass or paper in asphalt.

Typically, the overall thickness of the two differs. No. 30 (also known as 30-pound) is slightly more expensive but is thicker and more durable than 15-pound.

Between the plywood decking below and your shingles (or metal roofing), the felt underlayment offers a thin weather barrier. While the felt itself helps provide some resilience against weather effects like hail and debris, the asphalt finish is waterproof.

Synthetic Roofing Underlayment

Strong, long-lasting polymers are used to create synthetic underlayment. It is becoming the recommended roofing underlayment among professionals since it gives your roof more strength and durability.

Several advantages of synthetic roofing underlayment over conventional felt roofing include:

• Lighter weight

• Increased durability

• Safer to install (won’t tear easily when stepped on)

• Deflects and resists more heat

• Almost completely water-resistant.

The components used in the proprietary composition of synthetic underlayment are not standardized. Your best idea is to conduct some research and ask your roofing contractor which type might be best for the roof being installed because there is a tonne of companies supplying these roof underlayment types.

Which Roofing Underlayment Is Best for roof

The sort of roof you are building will largely determine the answer to this inquiry. Climate, finances, and the amount of time required to complete the project are additional factors to take into account.

Felt is often the economical option most people select when installing a shingle roof. The "average" is 15 pounds, however 30-pound felt is recommended if you have a little additional cash to spend and want more durability.

On the other hand, synthetic underlayment is preferable if you're putting on a metal roof. Particularly in the southern part of the United States, metal roofing has a tendency to retain a lot of heat. For metal roofing, synthetic underlayment makes the most sense because it reflects heat more effectively.

Final Thoughts on Roofing Underlayment

No option is "correct" or "wrong" in this situation. When deciding which underlayment would be best for your new roof, there are many options and variables to take into account.

The tried-and-true 15- or 30-pound asphalt-saturated felt is fine for those on a tight budget. For a while, roofing felt served as the industry standard for underlayment.

If you decide to go with synthetic underlayment, there are a tonne more advantages available to you.