Different Types of Underlayment

The roof of your home or business is arguably one of the essential features of the building. It protects the inside of the structure from weather such as heavy rain, winds, heat, as well as reduces the noise and light contamination. The roof needs to be strong enough to handle everything that’s thrown at it. Each roof will use an underlay of felt, synthetic, peel & stick, or a combination of the three. These layers protect the interior of the roof and the house from water, pests, rodents, and other things that might get underneath the roof. At GSM Roofing, we use synthetic and peel & stick for the roofs we install. Here’s a breakdown of all three of these materials to help you understand what goes into the installation process.

What is the difference between synthetic and felt?

Both synthetic and felt are great to use to protect your roofs. Mainly it comes down to the area you’re in, the type of roof you’re getting, and what the installer uses the most. So what’s the difference between the two?

Synthetic underlayment is the newest material of the two, but it has proven its worth time and time again. It’s designed to be an all-over protective barrier that’s placed between the roof deck and the roofing material. It’s mechanically installed with staples or roofing caps, which is a better option.

  • This material can last for 40 years or more, depending on the supplier.
  • It’s more durable because it’s made of either polypropylene or polyethylene mixed with a polymer weaved together. It can hold up from tears, moving it into place, or other damage that might occur as it’s being installed.
  • Synthetic underlayment has a high-temperature tolerance, which is perfect for Texas heat. This is one of the reasons we prefer to use it over felt.
  • In the same sense, it doesn’t retain heat because it’s made from mid-to-lighter gray. Installers can easily handle it without the material being too hot.
  • It comes in larger rolls to cover more of the roof at a time.
  • It’s light-weight, averaging at about 2 to 4lbs per square foot.
  • It’s fire-resistant rating Class-A, which means if a fire breaks out, the roof will not catch on fire.

Peel and Stick is also a synthetic underlayment, but it has an adhesive backing to help with placement. That adhesive makes it ideal for low sloping roofs or spots where you need to “picture frame” areas. At GSM Roofing, we use commonly use a combination of synthetic and peel and stick synthetic.

Felt underlayment is one of the original roofing materials used. It’s used a lot for asphalt roofs and can go under many names such as roofing tar paper, felt paper, asphalt-soaked felt, felt underlayment, and more. Felt paper is an all-over roofing coverage. It can either be made of natural materials such as natural fibers, wood cellulose, and more. It can also be made from synthetic materials such as fiberglass or polyester, but it is not the same as the synthetic underlayment.

  • Whether the materials are natural or synthetic, felt underlayment is less expensive than synthetic underlayment. This is great for people who are on a strict budget with their roof remodel or are not too worried about the material used. The issue that might occur is that the rolls are shorter than a synthetic roll, so you’ll end up buying more to cover the roof.
  • It’s more commonly used, which means it’s readily available to most roofing companies who choose to use it. You can even find it at your local home improvement store.