The underlayment may not be as visible as asphalt shingles, yet it is an essential part of every residential roofing system. It’s the barrier that protects the roof from water intrusion in case the outer layer gets damaged. In this blog, home improvement contractor Minnesota’s 1st Choice shares an in-depth look at the roofing underlayment.
How Underlayment Works
A typical sloped roofing system features an inner layer called the roof deck and an outer layer, which can be made of asphalt shingles, sheet metal or slate, among others. Between these layers sit a sheet of waterproofing material called the underlayment.
The underlayment is attached to the decking material using fasteners and may be enhanced with adhesive-backed moisture barriers. Properly installed underlayment prevents moisture intrusion in the event that it penetrates the outer roofing layer. This happens when the outer material gets damaged or torn off or when rainwater backs up due to clogged gutters. It should be noted that the underlayment complements the other parts of a roofing system, not a substitute for it.
Types of Underlayment
Asphalt-Saturated Felt — Traditional underlayment is made of pulped paper and fabric saturated in asphalt, which is where it got its other name: “felts”. In addition to its water-repellent properties, felts improve the durability of a roof deck. Asphalt-saturated felts are affordable but have a relatively short life span.
Rubberized Asphalt — Rubberized asphalt consists of sheets of rubber. Despite its name, rubberized asphalt contains a small amount of asphalt. Its main advantage is its elasticity, which makes it the ideal underlayment for regions that experience extreme heat and cold. It helps mitigate common problems such as substrate movement. Unlike other types of underlayment, rubberized asphalt is adhered to the roof deck using specialty adhesives.
Non-Bitumen Synthetic Underlayment — Modern roofing systems are equipped with non-bitumen synthetic underlayment. It is made from hard-wearing plastics, such as polyethylene or polypropylene, giving it strength and elasticity, as well as moisture-repellent properties. Manufacturers like GAF offer products such as Shingle-Mate®, VersaShield® and RoofPro™, which cater to all types of roofing systems.
Minnesota’s 1st Choice is your leading provider of roofing and fence installation services. Give us a call at (507) 200-4422 (Rochester) and (651) 333-4520 (South Metro). You can also fill out our contact form to schedule an appointment. We serve customers in Rochester, MN, and the surrounding areas.
