What’s the Best Type of Underlayment for Asphalt Shingles?

What’s the Best Type of Underlayment for Asphalt Shingles?

When it comes to installing asphalt shingles, the roofing underlayment plays a crucial role in ensuring your roof’s longevity, performance, and resistance to the elements. Underlayment serves as a secondary layer of protection, safeguarding your home from water, wind, and ice damage. But with various types of underlayment materials available, it can be challenging to decide which one is best for your specific needs.

In this comprehensive guide, we’ll explore the different types of underlayment for asphalt shingles, how each material performs, and which one is the best choice for your roofing system. We’ll also cover the factors that influence your choice of underlayment, including climate, durability, and cost considerations.

What Is Roofing Underlayment?

Before diving into the specifics of the best type of underlayment for asphalt shingles, let’s first understand what roofing underlayment is and why it’s so important. Underlayment is a layer of material installed between the roof deck and the shingles. It acts as a protective barrier against moisture, wind, and other elements, providing an extra layer of defense to the structure of your home.

Think of underlayment as the “first line of defense” for your roof. Even though asphalt shingles themselves are designed to shed water, the underlayment acts as a backup if water manages to penetrate the shingles due to heavy rain, ice dams, or wind-driven water. Without underlayment, your roof would be vulnerable to moisture infiltration, which can lead to leaks, mold, rot, and other costly repairs.

Types of Roofing Underlayment

There are three primary types of roofing underlayment: felt paper, synthetic underlayment, and rubberized asphalt underlayment. Each type has its own set of advantages and drawbacks, depending on factors such as weather conditions, budget, and personal preference.

1. Felt Paper Underlayment (Asphalt-Saturated Felt)

Felt paper is the traditional roofing underlayment material that has been used for decades. It’s made from a combination of felt (typically made of fiberglass or organic materials) and asphalt, which makes it durable and water-resistant. Felt underlayment is available in two main types: 15-pound and 30-pound.

• 15-pound felt: Lighter and thinner, but still offers decent protection against water infiltration. It’s less expensive but less durable than the 30-pound option.
• 30-pound felt: Heavier and thicker, providing better protection against water and increased durability. It’s the more popular choice for homeowners who want added security.

Advantages of Felt Paper Underlayment:

• Cost-Effective: Felt paper is one of the most affordable options for roofing underlayment.
• Proven Reliability: This material has been used for years and has a long history of success.
• Easy to Install: Felt paper is lightweight and easy for roofing contractors to install.

Disadvantages of Felt Paper Underlayment:

• Vulnerable to Moisture: Felt paper is made from organic materials, which means it can absorb moisture. If not installed properly or if it’s exposed to prolonged wet conditions, it can deteriorate quickly.
• Heavy and Bulky: The 30-pound felt paper can be heavy and cumbersome to handle during installation.
• Prone to Cracking in Cold Weather: When exposed to freezing temperatures, felt paper may become brittle and crack, reducing its effectiveness.

2. Synthetic Underlayment

Synthetic underlayment is a more modern alternative to traditional felt paper. Made from woven polymers, synthetic underlayment offers superior strength, durability, and moisture resistance. It’s typically lighter, thinner, and easier to handle than felt paper, while also offering better protection against the elements.

Advantages of Synthetic Underlayment:

• Enhanced Durability: Synthetic underlayment is highly resistant to tears, punctures, and UV damage. It doesn’t absorb moisture like felt paper, making it more suitable for areas with high humidity or frequent rain.
• Lightweight: Synthetic underlayment is easier to handle and install, reducing the overall weight on the roof structure.
• Better Performance in Extreme Conditions: It remains flexible even in freezing temperatures, and its resistance to moisture prevents mold and mildew growth.
• Longer Lifespan: Many synthetic underlayments come with warranties of up to 50 years, making them a long-term solution.

Disadvantages of Synthetic Underlayment:

• Higher Cost: Synthetic underlayment is typically more expensive than felt paper, although the cost difference is often justified by its superior performance and longevity.
• Slippery Surface: Some synthetic underlayments can be slippery, which may pose safety risks during installation. However, some manufacturers offer versions with added traction.

Best for: Homeowners in areas with high rainfall, snow, or extreme temperatures will find synthetic underlayment to be a great option due to its resilience and weather-resistant properties.

3. Rubberized Asphalt Underlayment

Rubberized asphalt underlayment is a premium option that offers the highest level of protection against water infiltration. This underlayment consists of a rubberized asphalt compound combined with a reinforcing layer, often made from polyester or fiberglass. It’s a self-adhesive material that bonds directly to the roof deck, creating a watertight seal.

Advantages of Rubberized Asphalt Underlayment:

• Superior Moisture Protection: Rubberized asphalt underlayment provides exceptional water resistance and is ideal for areas with frequent rain, snow, or ice.
• Self-Adhesive: The self-adhesive nature allows the material to stick directly to the roof deck, eliminating gaps and providing an airtight seal.
• Ice and Water Barrier: Rubberized asphalt underlayment is often used in conjunction with ice and water shields to prevent ice dams, which are common in colder climates.
• Long-Term Durability: This material is resistant to moisture, mold, and mildew, offering excellent protection for many years.

Disadvantages of Rubberized Asphalt Underlayment:

• Cost: Rubberized asphalt is the most expensive underlayment option, making it less appealing for homeowners on a tight budget.
• Difficult to Install: Due to its self-adhesive nature, this material requires careful installation to ensure proper bonding and avoid wrinkles or air pockets.

Best for: Rubberized asphalt underlayment is ideal for homes located in areas prone to ice dams, heavy rains, or extreme weather conditions. It’s also the go-to choice for areas with steep slopes where water runoff is a concern.

Factors to Consider When Choosing Underlayment for Asphalt Shingles

Now that we’ve covered the main types of underlayment, it’s time to explore the factors that should influence your decision when choosing the best underlayment for your asphalt shingles. The right underlayment can make all the difference in the durability and performance of your roof.

1. Climate and Weather Conditions

One of the most critical factors when choosing an underlayment is the climate in which you live. If you live in an area with heavy rain, snow, or ice, you’ll need an underlayment that offers superior water resistance and protection against ice dams. Rubberized asphalt or synthetic underlayment is the best choice for such regions due to their excellent waterproofing and durability.

If you live in a warmer climate with mild rainfall, felt paper underlayment may be sufficient. However, for homes located in areas with fluctuating temperatures, synthetic underlayment may be the more reliable option due to its ability to withstand both extreme heat and cold.

2. Roof Slope and Design

The pitch of your roof can also influence the type of underlayment you choose. For homes with steep roofs, rubberized asphalt underlayment is often recommended because it provides an extra layer of protection against water runoff and helps prevent leaks. On low-slope roofs, synthetic underlayment is a great choice due to its strength and ability to withstand constant exposure to the elements.

3. Cost vs. Performance

While it’s tempting to opt for the least expensive underlayment, it’s essential to balance cost with performance. Felt paper is the most affordable option, but it may not provide the long-term protection that synthetic or rubberized asphalt underlayment offers. If you want peace of mind and a roof that will last, investing in synthetic or rubberized asphalt underlayment is often worth the additional cost.

4. Warranty and Longevity

When choosing an underlayment, consider the length of time you expect the roofing system to last. Many synthetic underlayments come with warranties of 50 years or more, which means you can expect the material to perform well over the long term. Rubberized asphalt underlayment often provides the most extended warranty coverage, making it an excellent option for homeowners who want to ensure their roof’s protection for decades.

Conclusion: Which Is the Best Underlayment for Asphalt Shingles?

The best type of underlayment for asphalt shingles depends on various factors, including your location, the climate, your budget, and the performance requirements of your roof. Here’s a quick summary of the best options for each scenario:

• Felt Paper: Ideal for homeowners on a budget or in regions with mild weather conditions. Felt paper offers basic protection but may not be the best option in areas prone to extreme weather.
• Synthetic Underlayment: Best for homeowners in regions with moderate to severe weather conditions, synthetic underlayment offers durability, water resistance, and a longer lifespan. It’s a balanced option for those looking for performance at a reasonable cost.
• Rubberized Asphalt Underlayment: The top choice for homeowners in areas with extreme weather conditions, including ice, snow, and heavy rain. It offers the highest level of protection, though it comes at a higher cost.

No matter which underlayment you choose, always ensure it is installed properly to maximize its effectiveness. A reputable roofing contractor can help you select the best underlayment material for your specific needs and ensure that it is installed correctly for optimal protection.

If you need expert advice or roofing services in Northeast Ohio, consider reaching out to S&K Construction and Remodeling LLC, your trusted Owens Corning Preferred Contractor in the region. We are dedicated to providing high-quality roofing services that offer both protection and peace of mind.