
An asphalt shingle roofing system is more complicated than some may expect. Its most noticeable parts are the asphalt shingles themselves, but there are still layers of other crucial components positioned just below the surface, all working together to keep your Washington home safe and intact against weather damage. One of these important components is the underlayment. But what exactly is the roof underlayment and why should homeowners pay attention to it?

What’s a Roof Underlayment?
You may hear this term when discussing roof repair or replacement with your local contractor. It refers to a thin waterproof or water-resistant material that’s installed directly between the roof deck and asphalt shingles. Basically, the underlayment provides the shingles a stable layer to rest on, while preventing the texture of the wood deck from being visible through the roof material.
Why Does Every Roof System Need an Underlayment?
On paper, the underlyament’s job doesn’t seem much, but it remains one of your roof’s most important components. In fact, a residential roofing system isn’t considered truly complete without it. Here are some of the things the underlayment can do:
- Provide Additional Weather Protection
While the asphalt shingles take the brunt of damage from inclement weather, it’s still possible for snow, rainwater, and high winds to get past them. When this happens, the roof deck, which is typically made of wood or wood composite, becomes susceptible to damage, too. But with a good roof underlayment in place, this shouldn’t be a problem. It acts as an extra barrier against the harsh elements, the final hurdle that snow, water and wind have to overcome before they can infiltrate your roof.

- Extend Roof Service Life
A residential roofing system is a huge investment, and you’ll want to make sure you can get the most out of it. The underlayment can help make that possible. It offers backup protection against moisture damage when the asphalt shingles have been compromised. Since the wood or wood composite decking isn’t exposed to moisture, there’s reduced potential for mold growth and rot — two major issues that can weaken the roof’s structural integrity when overlooked. Thanks to the moisture-preventing performance provided by the underlayment, however, avoiding premature roof failure and replacement is simpler.
Just how effectively the roof underlayment can keep your home dry will depend on two important factors: your choice of underlayment material and its installation.
Of What Is the Underlayment Made?
Most roof underlayments come in three types, and each one has its own pros and cons. Your available choices include:
- Rubberized Asphalt
Considered a premium roof underlayment (and with the price to match), rubberized asphalt does an excellent job at keeping the roof system sturdy and watertight. It looks and feels just like rubber — hence the name — and generally comes with a peel-and-stick design. Rubberized asphalt self-seals around the staples and nails of the roof, which is what makes it more watertight than its counterparts. If you’re not turned off with its higher cost, rubberized asphalt can give your roof the additional protection it deserves.

- Asphalt Saturated
The “grandfather” of the modern roof underlayment — that’s what asphalt saturated is. It used to be the go-to option for roof underlayment before it was eclipsed by newer and better alternatives. Despite that, asphalt saturated remains a viable choice for those looking for a roof underlayment that’s waterproof, readily available, and cost-effective. But keep in mind that this option has quite a few drawbacks. Asphalt saturated underlayment, for starters, is not ultraviolet (UV) resistant, so the roof contractor has to cover it with asphalt shingles immediately upon installation. It’s also less durable than its counterparts, so it damages easily and doesn’t last quite as long.
- Non-Bitumen Synthetic
This option is the “middle ground” between rubberized asphalt and asphalt saturated. In fact, it’s the underlayment that roofing contractors will likely recommend to you. Non-bitumen synthetic doesn’t use rubber or asphalt like its counterparts. Instead, it’s made of polypropylene polymers or polyethylene. Non-bitumen synthetic is more lightweight and has better tear strength and wind resistance than asphalt. It also doesn’t deteriorate as fast. Because this underlayment is impervious to UV rays, you won’t have to worry about it getting damaged in cases where the roof is left uncovered. And if you check the price tag of non-bitumen synthetic, you’ll find it far more reasonable than rubberized asphalt’s.
How About Something More Specific?
If you have trouble deciding on a good roof underlayment, KLIM Roofing & Construction may be able to help you out. We are a GAF Certified Weather Stopper® Roofing Contractor, so we can offer some of the highest quality roof underlayment options from this trusted industry name. Check these out:

- GAF Deck-Armor™ Premium Roof Deck Protection
This synthetic underlayment combines superior durability with premium breathable technology, allowing for exceptional protection against wind-driven rain and trapped moisture. It sets itself apart from conventional underlayments that absorb moisture and cause buckling and wrinkling in the roof. Since it’s lightweight and slip-resistant, this underlayment is fast and easy to install, even on steeply pitched roofs. And with our GAF Deck-Armor installed, you’re always sure that your roof system will be safe and mold-free, featuring an even surface that allows for a more seamless and finished look.
- GAF Tiger Paw™ Roof Deck Protection
The versatility of Tiger Paw underlayment makes it the ideal choice for a variety of roofing types, including asphalt shingles, metal, slate, wood shake, and mechanically attached tile. It’s made of premium UV-stabilized synthetic with a moisture control design, eliminating the potential for moisture infiltration in the roof deck. At the same time, it provides an extra protective layer against wind-driven rain that can damage the roof structure and home interior. Since Tiger Paw underlayment is designed for strength and resilience, it doesn’t rot or get brittle.
- FeltBuster®
Those looking for roof underlayment that combines value price with watertight performance should definitely consider this option. Its solid polypropylene construction allows it to resist tearing and moisture absorption. Compared to typical felt underlayment, FeltBuster lies flat and even on the deck to create a sleeker-looking roof system.

Where Do You Go for Quality Roof Underlayment Installation?
That’s an easy question with an even easier answer: KLIM Roofing & Construction. As a GAF certified roofer, we understand the importance of quality roof underlayment, and we also know that it’s just one of the many important components a complete roofing system should have. If your underlayment has worn down and failed, it can only mean your existing roof is already at the end of its life. Your next step should be roof replacement. Let us handle this project and we’ll make sure that every part of your roof, from the shingles to the underlayment, is installed to stringent quality specifications.
KLIM Roofing & Construction is not just a certified roofing company. We are also:
- Fully licensed, bonded and insured. We have the necessary credentials that make us eligible to perform residential roofing work in your area. Carrying significant worker’s compensation and liability coverage, we can ensure greater customer protection.
- Experienced. KLIM Roofing & Construction has served homeowners in Greater Seattle and Puget Sound for 15 years, providing only the highest quality solutions to all their roofing needs. Delivering superior workmanship that leaves no room for costly mistakes and unnecessary delays – that’s what we aim for and accomplish with every roof replacement.
- Well-reviewed. Many Washington homeowners and business owners have called on us to handle their roofing project, and we have never let them down. Our commitment to complete customer satisfaction is present in every five-star rating or review we’ve earned on Google My Business and Facebook.
