In our industry there are two main varieties of underlayment.
Roofing felt paper vs synthetic.
It will keep your roof dry even when water flows backward and in driving rain.
Felt is commonly sold in either 15 or 30 rolls measuring 36 inches wide.
Synthetic or felt roofing underlayment which is better.
Of course it is a bit more technical than that but this is the basic idea behind how felt works.
It was easy to use durable and even had alignment lines to help with the shingle installation.
When most people think of roofs they typically think of shingles or metal roofing.
What is roofing felt.
Asphalt felt and synthetic underlayments are products installed under all the roofing materials and directly on a roof deck.
Generally speaking roofing felt is a felt paper that is soaked in asphalt and other water resistant compounds to produce a membrane.
Felt paper and synthetic.
While felt is weighed by pounds per roofing square 100 square feet synthetics are rated by grams per square meter gsm.
Synthetic roof underlayment vs.
Weighs 7 5 to 12 5 pounds per roofing square 30 felt.
Roofing felt offers an additional layer.
The underlayment provides a secondary weather barrier against wind driven rain and snow.
Anywhere from 40 100 grams per square meter.
Weighs 16 to 27 pounds per roofing square.
The shingles are the primary weather barrier.
Felt paper also referred to as tar paper was the standard underlayment material in roofing for decades.
For these reasons nj roofing contractors increasingly use these synthetic materials instead of traditional felt.
Fast forward 170 years and roofing felt is still the most popular roofing material now used as an underlayment being installed today.
Felt underlayment 15 felt.
For decades roofers have fitted a layer of felt over a roof s sheathing or roof deck before installing shingles.
For example interwrap s rhinoroof can be exposed to uv rays for up to 60 days without any potential damage.
Additionally synthetic materials can withstand uv exposure much longer than felt paper so if progress needed to halt on a roof before the shingles were laid the material will not be damaged.
Prospectors during the california gold rush covered the roofs of their temporary shacks with roofing felt also known as felt paper or tar paper.
