What is underlayment?

Undlerlayment is the material that separates your roof structure from the roof final top. Think of it as underwear for your roof! The primary job of a good roofing underlayment is to keep your structure dry.

Roofing underlayment is applied to the structure or plywood decking to prevent water penetration. A roofing top coat (shingles, tile, rolled roofing) is then applied over the underlayment to protect it from the elements.

There are two basic types of underlayment. Felt underlayment and synthetic.

Crestwood uses synthetic underlayment in 100% of our projects. Why? Felt was invented in the 1850s, like many inventions of the 1800s we have greatly improved on them since. Synthetic underlayment is made of polymers which when properly installed will not dry out, tear and will stand the test of time.