When you look at your roof, what you see is shingles – most likely! Only a few people – apart from the roof contractors, know what lies underneath. And even fewer people really care to know details about their roofing system’s components. All everyone wants is to have a good roof. A roof that will protect them, look nice, last for years.
But if you think about it, one thing depends on the other. Roofs look good, protect and last for a long time when they are installed correctly and have the right components. And when it comes to shingle roof installation and the basic components of the system, underlayment is found at the top of the list. Let us tell you why.
What is underlayment?
Think of underlayment as a membrane. Consider it the tarp of your roofing system. It’s an essential material, one of the most important components of the roof. The roofers put underlayment on the roof’s deck – the plywood, covering the entire roof. Underlayment is particularly important on sections most exposed to the elements or running the risk of water pooling. And so, underlayment is put along the roof’s perimeter, on valleys, around skylights, vents – anywhere there’s a risk of water penetration indoors. And so, it’s easy to understand that the main purpose of underlayment is to protect from the elements.
How many types of underlayment are there?
• Felt underlayment
Traditionally, underlayment was made of felt. To this day, it’s broadly used in most roof installations. We are talking about a thick, heavy-duty felt paper whose one side is covered with asphalt. It’s there where the shingles bond to. This is the most cost-effective underlayment.
• Synthetic underlayment
Synthetic underlayment is a more advanced product, compared to felt. Overall, it’s more durable and thus, ideal for areas with harsh weather conditions and lots of rainfall.
• Rubber underlayment
Although not widely used, rubber underlayment combined with its felt counterpart provides greater protection – necessary in regions which experience heavy snowfall and rainfall. Due to its material, rubber underlayment is very strong – hence, ideal for roof valleys, around chimneys, and all parts that might be subject to water penetration.
Is underlayment important?
The purpose of underlayment is to protect. And so, that’s its advantage. Acting as the membrane that will keep the water from entering the home, underlayment prevents all sorts of problems – leaks, wood rotting, roof components saturation, attic damage. Since the deck of the roof is right under the membrane, it will be badly affected without underlayment. Or, if the underlayment is not installed correctly or at the most critical sections of the roofing system.
Underlayment protects wood from the rain but also from the heat, reflected from the shingles when they are over-exposed to the sun rays.
And there’s one more thing. Underlayment protects the home from the elements in the event of shingle damage. Shingles may break, fly off, get damaged. There’ll still be a tarp covering the roof, not letting the elements or insects in.
Things to know about underlayment
Do all roofs need underlayment? Your roof contractor would know since it’s a matter of local building codes too. In the same context, you need to check what’s included in the warranty of your shingles. It’s often required to have underlayment and thus, better protect the shingle roof.
In order to decide on whether or not installing underlayment under the asphalt shingles is a good idea, you need to consider – apart from the warranty and building codes, the roof style and the climate. If there are some high-risk water penetration sections, like skylights, valleys, chimneys, underlayment becomes necessary. Even more if your area takes lots of rain.
But you know what? Underlayment is good for your pocket, peace of mind, the roof longevity, your home’s integrity. Unless a roofer tells you “no, don’t install underlayment” for some reason, why not have it? After all, it’s one more layer of protection, one more line of defense against the elements. Who doesn’t want that?