Metal roofing is fast becoming one of today’s most popular roofing options, and can be used to replace existing asphalt shingle roofs with sound roofing structures. In this blog, residential roofing contractor Fortenberry Roofing takes a closer look at an important metal roofing component: underlayment.
What Is Underlayment?
Underlayment, also known as roofing felts, is a layer that acts as a waterproof barrier between the outer roofing material and the decking material. Traditionally, felts are made of paper soaked in asphalt, and are mechanically fastened to the roof deck. While this type of underlayment is still sold today as “organic” felts or tar paper, you’re more likely to find synthetic ones on new installations.
Underlayment on Metal Roofs
The installation process for metal roof underlayment is similar, but the materials used are different. During roof replacement, a layer of ice guard (or ice and/or water shield), which usually comes with a peel-and-stick adhesive backing. This layer covers breaks in the roof, including valleys. The rest of the roof will then be covered with mechanically-fastened or peel-and-stick underlayment.
Local building codes require a specific underlayment weight, but 30-pound stock is typically used. The relatively lighter weight of standing seam metal roofs offsets the increased thickness of the underlayment. An extra slip sheet layer made of red rosin paper, which helps keep the metal from sticking to the underlayment, may also be installed.
Why the DIfferences?
One of the advantages of thicker underlayment is it improves upon standard levels of waterproofing. Despite its durability, water may still infiltrate that first layer of metal under extreme circumstances. As a conductive material, heat can pass through metal. Therefore, the increased distance between the metal layer and the decking—even if it’s only a quarter-inch difference—can help reduce the heat absorbed through the roof during the daytime.
Fortenberry Roofing is the residential roofing company that you need for all your roofing needs. Give us a call at (806) 429-0822 or fill out our contact form. We serve customers in Littlefield and Hereford, TX.