The underlayment protects the roof from moisture damage and can be considered as a roofing system’s unsung hero. In today’s post, the local roofing contractors at Roofmasters Roofing and Sheet Metal Company take a look at the different types of roofing underlayment, and how to choose the right one when you’re planning on getting a new roof.
Why Do Roofs Need Underlayment?
The underlayment is a layer of material that is installed between the outer roofing material and the roof deck. Its main purpose is to protect the roof deck (and everything under it) from moisture infiltration. In addition to helping prevent problems caused by a leaky roof, the roof framing and decking are typically made of wood and are therefore vulnerable to rot.
Since most outer roofing materials such as asphalt shingles, tiles, and sheet metal are shingled — that is, multiple overlapping pieces, as opposed to a seamless layer — the risk of moisture infiltration from water backing up is always present. A properly-installed underlayment is a barrier that keeps moisture away from the roof’s vulnerable parts.
How to Choose the Right Kind of Underlayment
There are two types of underlayment:
- Felt paper. Also known as “organic” underlayment, felt paper is made of paper pulp soaked in asphalt. It’s more rigid than synthetic underlayment and is typically installed using adhesive.
- Synthetic sheets. Synthetic underlayment is the far more common variety and is made of plastics like polypropylene. It’s more flexible, weighs less, and can have features like expelling moisture from under it.
Roofers consider several factors when choosing the right underlayment for the roof, however the most important is the roofing type itself. Asphalt shingle roofs are typically matched with felt paper because their inherent rigidity contributes to the roof’s impact resistance, though some roofing manufacturers require using their own synthetic underlayment. Metal roofing systems, on the other hand, need synthetic underlayment to offset the heat absorbed by sheet metal. Synthetic underlayment is also ideal for use in hot and humid climates, while felt paper is best in most cold climates.
Roofmasters Roofing and Sheet Metal Company provides roofing services, including sheet metal fabrication, to customers in Hays and Colby, KS, as well as the surrounding communities. Give us a call at (785) 628-3614, or fill out our contact form to schedule an appointment.