Shingles may be the largest factor when it comes to protecting your roof from the elements, but they're not the only one. The underlayment below your shingles also has a crucial role to play. If you would like to learn more about the role of underlayment, as well as three of the most common types, read on. This article will provide a handy beginning guide to roofing underlayment.
The Basic Idea
Underlayment has two crucial roles to play in keeping your roof safe. First of all, it acts as a water-resistant barrier beneath your shingles. Given the vast number of seams and points of intersection of a roof, this is a necessary part of keeping water from penetrating down into the vulnerable sheathing of your roof. Yet underlayment also works to prevent moisture damage coming from the other direction.
As you probably know, hot air is less dense, and so it rises upward. That means that, no matter how well insulated, a certain proportion of warm air is continually escaping out of through the attic. When this warm air meets cooler air, the moisture present in it tends to condense--often on the bottom side of the shingles. Roofing underlayment keeps this moisture from directly touching your roof's wood sheathing, thus preventing such problems as mold, mildew, and rot.
Asphalt felt is the historically dominant material used for roofing underlayment. As its name would imply, it consists of a sheet of felt that has been thoroughly impregnated with a diluted emulsion of asphalt. This increases both its durability and its waterproofing properties. Asphalted felt comes in two different thicknesses 15- and 30-pound. While the 30-pound felt is more durable, for most purposes, the 15-pound version is more than suitable and considerably less expensive.
Asphalted felt has the drawback of having to be attached by means of fasteners. In other words, some type of nail or staple is used to physically attach the felt to the surface of the roof decking. This has the unfortunate drawback of allowing water to easily penetrate in the event of a shingle failure. Rubberized asphalt, on the other hand, manages to avoid this potential pitfall completely.
This material--a compound containing both asphalt and rubber or rubber-like ingredients--is coated with adhesive on one side. This allows the underlayment to be pressed directly into place with none of the nail holes associated with asphalted felt--a fact that makes rubberized asphalt both more protective and drastically easier to install.
For more information, contact Specialty Commercial Contractors Llc or a similar company.Share
29 September 2016
One thing I never realized about roofing is what a difference it can make in the appearance of a home. The roofing on my home was more than 20 years old before we got around to replacing it. As we were working with our roofing contractor to choose the materials that we wanted to use, I learned quite a bit about the many, many options that we had to consider. Our blog will show you several of the options and provide you with facts about each type of material that you can use. Hopefully, what we have included here will help you choose the roofing that will look and perform the best on your home.