As a roofing professional, it's important to give your customers insight into the work required and their available roofing options so that they can be sure the job will be completed to the highest standard possible for their budget. This is particularly true when it comes to roofing underlayment, the material that's installed between the shingles and the sheathing or roof deck.
You typically have two choices for underlayment: felt or synthetic. While traditional asphalt-saturated felt has generally been the go-to product, synthetic options are becoming more popular due to their durability and ease of installation. In many ways, when it comes to features and benefits, synthetic roofing underlayment can't be beat.
What's the Difference between Felt and Synthetic Underlayment?
Underlayment protects the roof deck from exposure to rain, wind, snow, and other debris; deadens the sound of rain or other elements hitting the roof; and provides an even surface for laying down roofing material. Additionally, underlayment is a requirement for many roofing warranties and system approvals.
Traditional roofing felt consists of paper or fiberglass mats saturated with asphalt. It provides economical protection, but it can't be exposed to the elements for long without deteriorating. It's also heavy to lift and can be slippery to walk on.
Meanwhile, synthetic underlayment uses polymers such as polypropylene and polyethylene to create a weather-resistant barrier against the elements. It generally costs more than felt, but it's more durable and easier to install. That said, if you're considering this material, it's important to do your research. Synthetic underlayment isn't standardized in the industry, meaning no two products are the same.
Benefits of Synthetic Roofing Underlayment
There are many reasons why you should choose synthetic underlayment over traditional roofing felt.
Water-Repellant
The plastic polymers used in synthetic underlayment provide excellent protection against water intrusion. For example, GAF Deck-Armor™ Premium Breathable Roof Deck Protection installed under your shingles helps protect your roof system from wind-driven rain and can help reduce trapped moisture.
Lightweight
Synthetic underlayment is lighter than traditional felt, which makes it easier to haul up to the roof and install.
Walkable
This underlayment has a slip-resistant surface, is more durable, and can stand up to foot traffic. Accordingly, GAF Tiger Paw™ Premium Roof Deck Protection is often chosen by installers looking for excellent traction.
Durable
Synthetic underlayment won't tear and can withstand extended exposure to ultraviolet light and moisture (typically between 90 and 180 days, depending on the product) without degradation. This durability translates into longer warranty periods and additional protection in high-wind areas. For instance, GAF FeltBuster® Synthetic Roofing Felt is Miami-Dade County Product Control and State of Florida approved, and has even earned the Good Housekeeping Seal.
Fire-Safe
When installed with specified roofing system components, synthetic materials can provide a UL Class A rating when used with UL Class A-rated shingles. Class A represents the highest UL rating, meaning the roofing materials can withstand severe fire exposure. These materials help protect buildings against flame spread and penetration into the interior.
Mold- and Mildew-Resistant
Because the material is designed to repel water, it's also more resistant to mold and mildew growth. This helps to protect building occupants from those allergens and the roof from undue damage, making it a great choice in high-humidity areas.
Long-Lasting Protection
The life expectancy for felt underlayment is 12 to 20 years, while synthetic underlayment can last 25 to 40 years, depending on the product.
Easier Installation
With lighter rolls and a slip-resistant surface, synthetic underlayment makes installation easier and safer. Additionally, it tends to come in wider and longer rolls that can reduce installation time, saving you time, energy, and potentially money.
Smoother Finish
Synthetic underlayment provides a smoother, wrinkle-free finish, which improves the look of the roofing material once the installation is complete. Felt underlayment may also absorb water and wrinkle or warp, making it harder for the roofing material to lay flat.
Selecting the Right Roofing Underlayment
When selecting the right roofing underlayment for a specific project, consider a few factors:
Code Requirements
Local building codes may require a certain type/weight of underlayment.
Manufacturer Requirements
The roofing material manufacturer may require or recommend a certain type/weight of underlayment to avoid voiding the roofing system warranty.
Climate
Breathable synthetic underlayment provides better protection for buildings in humid climates.
How Long the Underlayment Will Be Exposed
If there's a delay between underlayment and roofing installation, synthetic underlayment is less likely to degrade when exposed to UV and avoid wrinkling and bubbling.
Roofing Material Lifespan
For roofing systems with a long lifespan (25 to 40 years), synthetic underlayment provides protection for an equal period of time.
Budget
While synthetic underlayment may be more expensive, it provides superior performance and durability that may help homeowners save money over time, and potentially cut down on install time.
Curious to learn more about synthetic roof underlayment? Explore the different options GAF offers, so you can help your customers understand what would best suit their needs.
