The Importance of Underlayment in Roofing Systems

The underlayment is an unseen yet important part of any roofing system, and is the component that must not be skimped or overlooked. In today’s post, your local roofers at Diamond Roofing Specialists, Inc. explain how underlayment works with a complete roofing system.

How Does Underlayment Work?

Underlayment is the layer of material that sits right under the outer layer, and works as a redundancy measure in case the outer layer is punctured or damaged.  This is why parts of a building such as exterior walls and foundation slabs require underlayment. On roofing systems, the underlayment is the layer that goes over the decking, right under the outer layer of material such as asphalt shingles, sheet metal or tiles, among others.

The main purpose of underlayment is to protect the decking and underlying layers of the roof. Being made from timber and processed wood products, these components are vulnerable to rot, mold growth and other kinds of damage caused by trapped moisture. Additionally, it helps preserve the condition of the decking. Given that it can be used for a second installation, it can help reduce the cost of your next roofing replacement.

Types of Underlayment

When planning for a roof replacement, your roofer may offer more than one type of underlayment. Here’s a quick comparison:

• Felt underlayment, also known as tar paper or by its full name, “asphalt-soaked felt,” is the oldest type of underlayment. It’s made of pulp from recycled paper products soaked in asphalt or bitumen, and is typically used with slate or tile roofing.
• Self-adhered underlayment is made with asphalt and rubber polymers. This is the only type of underlayment that is adhered to the roof deck — others are installed using fasteners. Self-adhered underlayment is typically used on low-sloped roofing, but can be combined with other types to protect vulnerable areas such as eaves, valleys and chimneys.
• Synthetic underlayment is today’s most popular type of underlayment because of features like tear-resistance and lighter weight. Some synthetic underlayment products have the ability to wick moisture from underneath, which can help keep the roof deck dry in case of moisture infiltration.

Our roof repair and installation professionals at Diamond Roofing Specialists, Inc. can help you choose the right underlayment and other roofing options for your new roof. Give us a call at (203) 754-7884 or fill out our contact form to schedule an appointment. We serve communities in New Haven, Bridgeport and Waterbury, CT.