Synthetic Roofing Underlayment vs. Felt Roofing Underlayment

Traditional roofing felt has long been the roofing underlayment of choice among builders and contractors. This is in large part because for decades, there haven’t been many options to choose from. These days, however, there is a growing demand for alternatives — and Epilay is meeting that demand by providing synthetic options to traditional felt roofing underlayment. Let’s take a look at the purpose that underlayment serves as well as the things you’ll need to consider when choosing between synthetic and felt roofing underlayment.

What is the Function of Underlayment?

Underlayment is an essential part of any roofing system and there are a variety of reasons for this. First, a good underlayment preserves the lifespan of a roof by serving as a barrier between the top layer of roofing material and the roof deck’s substrate. As such, a good underlayment helps keep the tar in shingles and other roofing materials from soaking into the wood beneath the underlayment.

Roofing felt also serves as a secondary moisture barrier in existing roofs as well as a temporary moisture barrier while a new roof is being installed. Should damage occur to the roof after installation, felt acts to help prevent moisture damage to the roof deck.

Most traditional roofing felt is made of paper that is soaked in asphalt and other compounds to give the paper water resistance, and it’s available in 36-inch wide rolls, usually in 15# and 30# weights. These paper underlays have been the standard in roofing for decades because they are the most prominent material available and as such, traditional felt underlays are what contractors are used to using. Compared to synthetic materials, traditional felt is less expensive, plus it’s readily available to builders.

The Advantages of Synthetic Roofing Underlayment

Thinking about making the switch from felt underlayment to synthetics? While it will cost more, for the price, synthetic will give you a lot of advantages.

General Benefits of Synthetic Underlayment

Below, you’ll find the advantages of synthetics that everyone will enjoy — homeowners and contractors alike.

• Synthetic underlayment lasts longer than traditional roofing felt, which makes it a better investment for homeowners.
• It’s also more water-resistant, which means greater protection for the roof deck should the primary roofing material fail.
• Some underlayments — specifically peel and stick underlayments — can create a barrier that is impervious to water.
• Synthetics don’t rot, buckle or crack, which means they’ll provide a sound barrier for years to come.
• Traditional underlayment needs to be covered immediately — and that can be problematic when shipping delays or other issues mean that the primary roofing material can’t be installed right away. With synthetics, you’ve got some time. Epilay’s Plystik products can handle exposure for up to 180 days, and Epilay’s Protectite products can be exposed for up to one year.
• Synthetics allow you to mix and match underlayments, which is something you can’t do with felt. For instance, use peel-and-stick along valleys and edges, but save costs with non-adhesive synthetics elsewhere on the roof.
• Synthetics are more temperature resistant. High heat causes felt to leach tar and other compounds while cold can cause it to crack. Synthetics won’t leach chemicals, and they don’t get stiff in colder temperatures.
• It can be easier to create a code-compliant roofing system with synthetic—especially in areas like Florida that feature tough code requirements.

Benefits for Contractors

These are advantages that contractors in particular will benefit from.

• The surface of synthetic roofing underlayment is generally slip-resistant, making it easier for workers to move around on steeply pitched roofs as compared to traditional felt.
• Speaking of walking around on underlayment, roofing felt can be quite fragile. Synthetic has the strength and tear resistance to stand up to foot traffic during installations or repairs.
• There is also much more in the way of variety — Epilay’s products come in several weights, and there is both nail-in-place underlayment and peel-and-stick underlayment, which can make installation easier.
• Synthetics are lighter than traditional underlayment, so it’s easier to work with rolls of synthetic underlayment versus heavier rolls of traditional underlayment.
• Another advantage in high heat situations is that synthetics are light in color — roofers will be more comfortable without a black surface beneath them to absorb the summer sun.

As you can see, while synthetic underlayment may cost more, that’s about the only disadvantage. It’s faster and easier to install, offers a whole lot more protection against the elements, and it’s safer to work with.

Epilay’s Plystik Plus and Protectite Lines

If you’re considering making the switch to Epilay’s synthetic underlayment, then there are a few things you’ll need to know before you choose between our Protectite and Plystik Plus. Plystik Plus is a peel-and-stick underlayment, which means there is no need to nail it in place. It also features GripWalk, which ensures that the top layer of the underlayment has a high-traction surface, even when the underlayment is moist. Additionally, GripWalk makes the surface of the underlayment cooler, making it easier on workers during the summer heat. Plystik Plus and Plystik SA-250 can be used with a variety of roofing materials, including asphalt, shakes, metal roofing, and slate.

Protectite is a line featuring four different products: Plasfelt, which is the lightest underlayment, followed by Superior, Ultra, and Platinum. Each features the same GripWalk system, and like traditional underlayment, it is installed by nailing it into place.

They all have varying specifications, which lets you choose the perfect product for the job. For example, Plasfelt is ideal for shingles and metal roofing — and it offers 6.5 MIL thickness in a roll weighing only 21 pounds. At the other end of the line, Platinum features 17 MIL thickness in a 37-pound roll — plus a longer warranty to match. It is recommended not only for shingles and metal, but also for materials that need heavier underlayment, like slate, concrete, and clay tiles.

There is a lot to consider when making the choice between synthetic roofing underlayment versus felt underlayment, but if you’re looking for longevity, a better work surface, and better protection for the roof deck, then synthetics might just be the way to go!