The underlayment is the part of roofing systems that protects the roof deck from water infiltration, and acts as a secondary barrier in case of outer roofing failure. In today’s post, local roof replacement contractor Expert Contracting shares a look at how underlayment works, and what makes it an important part of sloped roofing systems.
How Does Roofing Underlayment Work?
Underlayment is installed between the roof deck and the outer layer of roofing material, which can be asphalt shingles, standing seam metal or wood shakes. There are many types of underlayment to choose from, but the function is the same: it keeps the roof deck dry if the outer roofing layer is punctured, damaged or torn off.
The installation process is fairly simple. Specially-designed fasteners are applied to hold the underlayment on the roof deck, while seams are installed using adhesive. If properly installed, it creates an unbroken barrier that spans an entire roofing plane. Underlayment is not designed as a substitute for the outer roofing material. You need to call a roof repair contractor like us if the underlayment is exposed due to roof damage.
Types of Underlayment
The following are the types of underlayment used in residential roofing:
Asphalt-Saturated Felts — This type is known as “traditional” felts, and is made with pulped fabric and recycled paper, then soaked in asphalt. This type of underlayment adds stiffness to the roof and improves upon its impact resistance.
Rubberized Asphalt — Despite the name, rubberized asphalt is mostly made of rubber. This type of underlayment is far more elastic than other types, which makes it ideal for applications such as roofing in extremely cold and/or warm regions. This is the only type of underlayment that requires full adhesion to the roof deck.
Non-Bitumen Synthetic Underlayment — You’re probably most familiar with this type of underlayment, as most roofing manufacturers offer this as part of their roofing systems. Non-bitumen synthetic underlayment is made of polyethylene or polypropylene, and resembles tarpaulin. Roofing manufacturers like GAF offer “breathable” underlayment, which allows moisture to evaporate from the roof deck.
Searching online for local roofing companies for your next roof repair or installation? Call Expert Contracting at (716) 572-7303. You can also fill out our contact form to schedule an appointment. We serve customers in Hamburg, NY, and surrounding communities.