The roof is the most important part of your home. It’s what protects the entire rest of the structure from the weather—most notably, snow and rain, but also wind, heat, and cold, too. That’s why it’s smart to choose great building products to make an exceptional roofing system.
One of the most important parts of a roofing system? The underlayment! Underlayment serves several purposes. It makes for a good base on which to install the top layer of roofing, and it also serves as a shield for any moisture that might penetrate shingles or other roofing products.
You can also look at underlayment as something of a backup plan. Should high winds lift shingles or blow them away, a good underlayment will offer some protection against wind, rain, and snow. Similarly, during a roofing job, some underlayments, like synthetics, can be left exposed for longer periods of time, which takes the stress out of the wait if there is a delay between installing the underlayment and placing shingles or another roofing product over the top of it.
If you’re wondering how to choose roofing underlayment, a good place to start is with the best synthetic roofing underlayment products out there. Here’s an overview of the different brands available along with their pros and cons!
Tyvek Protec 120 Roof Underlayment
Tyvek is a good choice as an underlayment to roofing products other than asphalt shingles—things like cedar shingles and metal roofing. It’s also a fully weatherproof underlayment, which is a huge advantage in areas that see a lot of extreme weather events. Installers love it for the textured surface, which makes it easy to walk on, and also because it’s a very lightweight product, which means it offers a lot of protection while making it easier to roofers to haul the rolls up to the roof deck.
The biggest drawback to Tyvek 120 is its UV resistance. It boasts three months, which is superior to asphalt felt, but other synthetic underlayment products can withstand up to a year of UV exposure, which can prove crucial when there are serious delays in building supply shipments or in heavily storm-damaged areas where builders may need a long time to make repairs to a lot of roofs.
Grace Select Roll Roofing Underlayment
This one is a peel-and-stick product, which means it comes with lots of advantages. Installation is easy, and because it’s a self-sealing product, it will seal around nails and seams, offering extra protection against water infiltration.
As peel and stick underlayments go, however, this one is on the thin side—only 25 mils, as compared to the 48-mil thickness that you’d get with Epilay Plystik Plus or another, similar product. While the lightweight isn’t an inherent problem, it does mean that it is less resilient than other, thicker types of peel and stick underlayment.
Owens Corning ProArmor
Owens Corning is a household name among building products, and with good reason. Like much of what the company produces, ProArmor underlayment is a great synthetic felt that offers a lot of water resistance in a light, thin product. It comes with a slip-resistant surface and button caps, which makes it much safer for roofers who have to walk across it, and it has a light gray surface, which makes working conditions cooler when installing this underlayment in hot weather.
Drawbacks for this underlayment include versatility and limited UV exposure. This underlayment was designed to be used with asphalt shingles, so if you’re installing some other type of roof, you’ll need a different product. Where UV exposure is concerned, ProArmor can only withstand 30 days, which is on the low end of the scale when you consider that other underlayment products can be left exposed up to a year.
GAF TigerPaw Underlayment
This is another great choice for walkability—featuring a specially designed surface to make it safer—and also for durability. TigerPaw is up to 600% stronger than #30 asphalt felt, and while it isn’t completely waterproof, it is highly water-resistant.
TigerPaw’s main disadvantage lies in its water resistance—other products can be made completely waterproof if need be—and in its weight. It’s among the heavier underlayment products out there, coming in at about 40 pounds, which makes it harder for roofers to lift as opposed to lighter rolls that offer the same level of protection.
RhinoRoof U20 Underlayment
This one is a tough product—up to 12 times stronger than #30 felt. It also features wide rolls, which means each roll covers 17% more per lap. In other words, less work for installers! It’s inert to mold growth, features a slip-resistant walking service, and it’s flexible and easy to work with in low temperatures.
RhinoRoof’s major drawback is UV exposure limits. It can be left exposed for up to 60 days, which is longer than some products, still not as much as the year of exposure protection that other products offer.
Epilay offers an entire line of synthetic underlayment products all suited to different needs. In the Protectite line, there are four different grades ranging from Plasfelt, which is a lightweight synthetic, all the way up to Protectite Platinum, which is a 17-mil underlayment with the tear strength needed to withstand installation beneath tough roofing products like metal, slate, concrete or clay. These underlayments are designed to offer the utmost in water resistance, they’re highly tear-resistant, and installers find them easy to work with. They also feature up to one year of UV resistance, which means these underlayments can be left exposed for quite a long time.
In addition to the Protectite line, Epilay also offers Plystik Plus, a peel-and-stick underlayment with 48-mil thickness that features Ice Dam Protection, extreme wind and water resistance, and the durability to be used beneath metal, shake, slate, and more.
One of the big features of Epilay underlayment is the anti-skid layer on the surface. In addition to the lightweight of these rolls, which makes it easier for workers to haul them up onto the roof, the anti-skid layer, known as GripWalk, means that roofers can walk across this underlayment with less risk of slipping and falling.
The biggest disadvantage to Epilay underlayments can be the price. At the higher end of the line, as with Plystik Plus or Protectite Platinum, these underlayments will cost more than thinner products—but you’ll be paying a premium for unparalleled protection and a product strong enough to be installed with just about any roofing material imaginable.
When it comes to the pros and cons of synthetic roofing, there are a lot more pros than cons, particularly compared to asphalt felt, which has been the standard for decades. Any of the above products will perform better and outlast asphalt, which tends to tear easily, offers less in the way of moisture resistance, and has very little UV resistance. Among synthetics, the choice comes down to the best product to suit the primary roofing material along with factors like your budget and the length of time the underlayment could be left exposed.