Underlayment: The Foundation of BC Roofing

This week we’re taking a closer look at the basics of roof underlayment, how it functions and various types. Traditional shingles allow for lots of gaps or seams in a roof covering, which means there must be a secondary layer of protection between the roofing material and the structure of your home. This is especially important in rainy climates like ours! Underlayment performs this function, repelling water that penetrates the top layer of shingles.

All types of BC roofing underlayment are manufactured in roll form. The most common type of underlayment is roofing felt, AKA tar paper or “builder’s felt,” made by injecting paper or a fibrous material with a tar/asphalt mixture. If green building is one of your priorities, paper-based asphalt felt is an organic option, though it does tend to buckle or wrinkle under shingles if it gets wet or moist, causing an unattractive overall appearance.

Advances in technology and materials have resulted in different features, such as synthetic underlayments made from polypropylene, polyester or fiberglass fabric. The benefits of these synthetics include a lighter weight than felt, and a non-slip surface that protects roofers from harm. In addition, synthetics are more durable than felt when exposed to wind, rain and run for long periods, and can withstand the elements for up to six months. In the aftermath of Hurricane Katrina, New Orleans roofing contractors used synthetic underlayments as a temporary roofing solution for this reason. “Breathable” roof underlayments allow water vapor to escape from the attic, preventing mold growth and rot on the wood structure.

While installation is relatively simple, roofing underlayment should only be installed by professional Vancouver roofing contractors who understand the weather demands of the region and can ensure proper water management techniques are employed. The right underlayment for your roof will keep moisture, cold and heat out, lengthening the life of your British Columbia roofing and preventing costly repairs down the road.