There are lots of types of underlayment out there, and they’ve all got their advantages and disadvantages. Some perform better in extreme heat, some are designed to withstand moisture, and so on.
What’s best for areas that experience a lot of cold and snow? For these kinds of conditions, you’ll need an underlayment that not only provides an excellent moisture barrier to keep snowmelt from harming your roof deck, but you’ll also need something that is pliable enough to remain flexible so that it doesn’t crack as temperatures dip below freezing.
Below, we’ll take a look at different types of underlayment so that you can judge what the best options are.
Traditional Asphalt Underlayment
This is the underlayment that many roofers are most familiar with because asphalt paper has been around for decades. In all those years, it did the job—but modern technology means that there are now alternatives out there that can stand up to cold and snow better.
While asphalt paper underlayment is among the most affordable varieties, it does have a couple of problems with regards to cold and snow. First of all, it is impossible to make a truly watertight seal with this type of underlayment. Fasteners, even the types designed to provide seals around nail heads, can still let a little bit of water seep through, particularly where snow and ice dams form along the edges of a roof.
Another issue with this type of underlayment is in its construction. Asphalt stiffens in the cold, which means that it can crack and tear a bit easier since it’s not as pliable. Consequently, in areas where cold and snow happen each winter, asphalt underlayment tends to break down relatively quickly compared to other types of underlayment.
Synthetic underlayment is definitely a step up from traditional roofing felt where cold and snow are concerned. One of the biggest advantages is that the materials used to create synthetic underlayment don’t become brittle in cold weather, unlike asphalt tar. This means it will stay pliable, which translates to less chances that it will crack.
Additionally, most synthetic underlayments—like Epilay’s line of Protectite products—are water repellent and non-absorbent, which provides additional protection against the moisture infiltration that can happen with snowmelt and ice damming.
Ice and Water Shielding
Underlayment that features ice and water shielding is the best bet for cold, snowy environments. Typically, these are peel and stick varieties of synthetic underlayment—just like Epilay’s Plystik Plus, which features Ice Dam protection.
The advantages to this type of underlayment are twofold: It gives you the flexibility and durability of synthetic underlayment, which means the material won’t become brittle and crack as temperatures dip. The other, larger advantage is that peel and stick underlayments featuring ice and water shield form a tight seal to the roof deck. The adhesive means that fasteners aren’t required, which means no punctures where moisture can seep through, and these underlayments also seal around the seams, which is another likely spot for water infiltration with other types of underlayment.
This is why roofers will often use peel and stick underlayment along the edges of a roof where ice dams are likely to form and cause water to pool—because it provides an impervious barrier that protects the roof deck. However, in environments where cold and snow can be extreme, it doesn’t hurt to cover an entire roof in underlayment with ice and water shielding to keep the roof deck safe and sound.
Peel and stick underlayment tends to be the most expensive of the three options—but because it prevents moisture infiltration that can result in damage to the home’s structure or mold problems, it is worth the extra cost. The best way to choose the right underlayment according to seasonal weather concerns is to judge temperatures and snowfall year-round. In climates where temperatures swing between extremes, and homeowners see a lot of snow, peel and stick underlayment is a wise investment!