Roofing underlayment is a water-resistant or waterproof barrier material that is installed directly onto your roof deck. It is applied under all other roofing materials as an added layer of protection from severe weather.
There are three main types of roofing underlayment:
Non-bitumen synthetic underlayment. This is also known as “synthetic underlayment.”
Rubberized asphalt underlayment
Asphalt-saturated felt and synthetic underlayment are water-resistant. Rubberized asphalt underlayment is waterproof.
Why do you need roofing underlayment?
It’s a moisture barrier.
Roofing underlayment provides your roof with an extra layer of protection that shingles alone can’t match.
Your shingles serve their own purpose: they’re the first line of defense. Shingles reflect the sun’s rays, withstand wind and block precipitation.
But shingles overlap and aren’t sealed at all corners. They can be lifted by strong winds. This makes shingles vulnerable to tear-off or infiltration by wind-driven rain. Shingles can become brittle from ag. The heat of an unventilated attic can cook your shingles, too.
Water-resistant roofing underlayerment
Water-resistant underlayment is enough for the surfaces of most roofs. It provides the protection that your roof needs during and after installation.
Even without the added protection of shingles, a superior product can withstand some seriously extreme weather.