Quarve Contracting
Thursday 2 May 2013

What Is a Roof Underlayment?

Posted by at 9:00 AM

A quality roofing job involves much more than the shingles or other exterior roofing material you can see.  What's just as important is what you can't see - the materials underneath the top.  When you’re getting ready to replace your roof, you probably want to know about the different layers necessary for a proper installation. One common term you might be wondering about is “underlayment.” What It Does This important part of the roof is what protects the underlying wood roof deck from moisture.  Over the course of your day, water vapor rises through your home and into your attic, where most of it is sent to the outside through vents. What’s left over is trapped between your home and the shingles of your roof. Sometimes, water from a Minneapolis thunderstorm, for example, will make its way past the shingles, which can cause huge problems.  The underlayment is what prevents it from settling into the wood and causing it to rot. It also protects the shingles of your roof from any sap which may still be in the roof timbers making up your roof deck. This is an important issue when it comes to asphalt roofing especially, because sap causes asphalt to deteriorate more quickly than usual. What It’s Made From Underlayment is usually made from one of three materials. Felt There are two different types of felt. One is called #15 felt, which is generally thought of as being the best material for general roof installation. The other is called #30 felt, which is often used when installing metal roofs. Synthetic This is a newer trend in the world of roofing, and very promising. It’s designed to allow maximum ventilation, while providing excellent water proofing at the same time. It also stands up to the force of a high impact nail gun far better than the felt options. Leak Barrier Membranes These membranes are usually used as an extra layer of protection around valleys and along the edges of your roof. It has a sticky backing and is made out of a flexible, rubber-like material. The next time you talk to your roofing professional, feel free to ask them about what type of underlayment they plan to use on your roof. Quarve Contracting has been providing quality roofing services in the Twin Cities metro area for three decades.  Hundreds of Minnesotans have trusted us to protect their homes.