What Are the Best Underlayments for an Asphalt Roof?
When it comes to installing an asphalt roof, the shingles may be the most visible component, but the underlayment is just as important.
Acting as a protective barrier between your shingles and roof deck, underlayment helps prevent water infiltration, improves durability, and enhances overall roof performance. But with different types available, how do you choose the best one?
For over a decade, Rescue My Roof has been a leading educator in the roofing industry. We’ve helped thousands of homeowners make educated decisions for their homes. Now, we’re here to help you, too.
This guide will break down the best underlayments for asphalt roofs and what homeowners should consider before making a decision. Ultimately, you’ll know how to select the right roofing underlayment for your needs.
Why Is Roof Underlayment Important?
Roof underlayment serves several crucial purposes:
- Water Protection: It acts as a second line of defense against moisture, preventing leaks caused by heavy rain, ice dams, or wind-driven rain.
- Improved Durability: A quality underlayment can extend the lifespan of your roofing system by providing additional protection against weather damage.
- Code Compliance: Many building codes require a specific type of underlayment to meet safety and performance standards.
- Shingle Performance: Underlayment prevents shingles from sticking to the roof deck and provides a smooth surface for proper shingle installation.
Types of Asphalt Roof Underlayment
There are three main types of roof underlayment commonly used with asphalt shingles:
1. Asphalt-Saturated Felt (Traditional Felt Paper)
One of the oldest and most widely used options, asphalt-saturated felt—often referred to as “felt paper” or “tar paper”—is made from cellulose or fiberglass that is coated in asphalt.
Pros:
- Affordable and widely available
- Provides a good moisture barrier
- Easy to install
Cons:
- Less durable than synthetic underlayment
- Absorbs water, which can cause wrinkling and deterioration over time
- Heavier, making it more challenging to work with
Best for: Homeowners on a budget or those replacing older roofs with traditional materials.
2. Synthetic Roof Underlayment
Synthetic underlayment is made from engineered polymers, offering superior strength, durability, and weather resistance compared to felt.
Pros:
- Stronger and more tear-resistant than felt
- Lightweight and easier to install
- More resistant to mold, UV exposure, and water absorption
- Often comes with slip-resistant coatings for improved safety
Cons:
- Typically more expensive than felt paper
- Some brands may require specific fasteners for installation
Best for: Homeowners looking for long-lasting protection and superior performance in extreme weather conditions.
3. Rubberized Asphalt Underlayment (Peel-and-Stick)
Rubberized asphalt underlayment is a self-adhering membrane that provides the highest level of waterproofing protection.
Pros:
- Fully waterproof and self-sealing around nails
- Best protection against ice dams and heavy rain
- Ideal for high-risk areas like valleys, eaves, and low-slope sections
Cons:
- More expensive than other options
- Can be challenging to install without proper training
Best for: Homes in areas with heavy snowfall, frequent storms, or high humidity.
How to Choose the Best Underlayment for Your Roof
When deciding which underlayment is best for your asphalt roof, consider the following factors:
Climate: If you live in a region with harsh winters or heavy rain, a rubberized asphalt underlayment offers the best protection. For milder climates, synthetic or felt underlayment may be sufficient.
Budget: If cost is a concern, asphalt-saturated felt is the most budget-friendly option. However, synthetic underlayment provides better long-term value.
Roof Slope: Low-slope roofs are more prone to water pooling, making waterproof underlayments like rubberized asphalt a smart choice.
Longevity: If you’re looking for a long-lasting roof, synthetic underlayment provides the best combination of durability and performance.
Installation & Compatibility: Always check with your roofing contractor and manufacturer guidelines to ensure the underlayment you choose is compatible with your shingles and local building codes.
Selecting the Perfect Roof Underlayments
Choosing the right underlayment for your asphalt roof is essential for protecting your home from leaks, extreme weather, and premature roof failure. While asphalt-saturated felt remains a popular choice for budget-conscious homeowners, synthetic and rubberized asphalt underlayments offer superior durability and protection.
If you’re planning a roof replacement, consult with a professional roofer to determine the best underlayment for your specific needs. A well-installed underlayment will enhance your roof’s performance and longevity, giving you peace of mind for years to come.
Learn more with “What Is A Roof Underlayment” and “How Long Does A Roof Replacement Take?”
Are you experiencing roofing issues in southeastern Wisconsin? Rescue My Roof is here to help. Contact us today to get a free estimate.
