How To Find The Best Roof Underlayment For Asphalt Shingles

Choosing the best roof underlayment for asphalt shingles is one of the most important decisions you can make for your home’s protection and longevity. The underlayment serves as a hidden yet vital layer between your shingles and roof decking, providing waterproofing, insulation, and stability. Homeowners in Ankeny and surrounding areas benefit from understanding their options to ensure their roofs stand up to Iowa’s changing weather.

• Added protection: The underlayment provides a moisture barrier to prevent leaks and water damage.
• Enhanced durability: It supports the shingles, helping them last longer and perform better.
• Energy efficiency: Some underlayments reflect heat, reducing attic temperatures and energy bills.

What Is Roof Underlayment and Why It Matters

Before choosing the right product, it’s important to understand the role roof underlayment plays in your roofing system.

This layer sits directly on top of the roof deck, underneath the asphalt shingles. It protects against water infiltration, wind-driven rain, and ice dams. Without proper underlayment, even high-quality shingles may not perform as intended. It is a critical component in ensuring your roof can withstand severe weather; learn more about restoring your system after heavy gusts in our guide to wind damage repair.

In climates like Ankeny and surrounding areas, where rain, humidity, and snow are common, underlayment acts as your roof’s first line of defense against moisture-related issues.

3 Main Types of Roof Underlayment

While all underlayments serve a similar purpose, not all materials are created equal. Each has its strengths, costs, and ideal applications depending on your home’s needs.

1. Asphalt-Saturated Felt

Also known as tar paper, asphalt-saturated felt is the traditional choice for roofing projects. It’s made from cellulose or fiberglass material soaked in asphalt for waterproofing.

• Cost-effective: Asphalt felt is one of the most affordable options.
• Variety: Available in 15-pound and 30-pound thicknesses, with 30-pound offering better durability.
• Downside: It’s heavier, more prone to tearing, and less water-resistant than newer materials.

2. Synthetic Underlayment

Synthetic underlayment is a modern alternative made from polypropylene or polyethylene. It’s lightweight, tear-resistant, and designed to outperform felt in nearly every category.

• Durability: Resistant to moisture, UV exposure, and mold growth.
• Safety: Provides a slip-resistant surface for roofers.
• Longevity: Can last significantly longer than felt, especially under asphalt shingles.

For homeowners in Ankeny and surrounding areas, synthetic underlayment is a smart investment for long-term weather protection.

3. Rubberized Asphalt Underlayment

Rubberized asphalt offers premium waterproofing capabilities. It’s often used in high-risk areas like valleys, eaves, and around penetrations such as vents and chimneys.

• Superior waterproofing: Contains rubber polymers that self-seal around nails.
• Flexible: Adapts well to temperature changes and complex roof shapes.
• Premium cost: More expensive but ideal for homes in areas prone to ice dams and heavy rain.

7 Key Factors To Consider When Choosing Underlayment

To find the finest roof underlayment for the best asphalt shingles, consider how your roof structure, environment, and budget align with the product’s performance features.

1. Weather Conditions: Homes in Ankeny and surrounding areas experience temperature swings, so choose underlayment that resists moisture and heat.
2. Roof Pitch: Steeper roofs may benefit from synthetic underlayment for better water runoff.
3. Budget: Felt is cheaper upfront, but synthetic options offer greater long-term value.
4. Installation Time: Synthetic materials are easier and faster to install, saving labor costs.
5. Longevity: Look for products with extended warranties to ensure lasting protection.
6. Material Compatibility: Make sure your chosen underlayment works well with asphalt shingles and local building codes.
7. Warranty Coverage: Check for manufacturer-backed warranties that protect your investment and give peace of mind.

How Underlayment Impacts Roof Performance

The right underlayment not only keeps your roof watertight but also influences the overall performance of your shingles.

Prevents Leaks and Water Damage

Underlayment provides a secondary barrier beneath shingles, reducing the risk of leaks during storms or heavy rainfall. This is especially beneficial in areas where snow or ice dams can cause water backup.

Extends Shingle Life

By limiting moisture exposure and stabilizing roof temperatures, underlayment helps asphalt shingles maintain their structure and color over time.

Boosts Energy Efficiency

Certain underlayments have reflective properties that reduce attic heat buildup, helping maintain comfortable indoor temperatures and lower utility bills.

Installation Tips for Proper Roof Underlayment

A great underlayment only performs well if it’s installed correctly. Working with an experienced roofing contractor ensures you get the most out of your investment.

• Clean surface: Make sure the roof deck is dry and free of debris before installation.
• Proper overlap: Overlap edges according to manufacturer recommendations to prevent water infiltration.
• Secure attachment: Use corrosion-resistant fasteners to hold the underlayment in place.
• Seal vulnerable areas: Apply additional protection around chimneys, skylights, and roof valleys.

In Ankeny and surrounding areas, where roofing materials face harsh weather conditions, hiring a certified roofing professional helps guarantee your underlayment performs as intended.

Comparing Felt vs. Synthetic Underlayment

Homeowners often wonder which option offers the best protection and value. Here’s how the two stack up.

Durability and Longevity

Synthetic underlayments generally last longer and are more resistant to tearing and UV rays. Felt, while reliable for basic use, can degrade faster under high heat or moisture exposure.

Installation Efficiency

Synthetic products are lighter and easier to install, reducing labor time. Asphalt felt can wrinkle or tear during installation, making it more challenging to handle.

Cost and Value

Although felt is cheaper upfront, synthetic underlayment offers better durability, fewer repairs, and lower long-term costs.

For most homeowners in Ankeny and surrounding areas, synthetic underlayment provides the best balance of protection, performance, and value.

When To Upgrade or Replace Your Roof Underlayment

Even the best roof underlayment for asphalt shingles won’t last forever. If your roof is aging or showing signs of damage, it may be time for replacement.

Warning Signs to Watch For

• Leaks or water stains: Indicate compromised waterproofing beneath your shingles.
• Wrinkled or sagging roof: May suggest trapped moisture under the underlayment.
• Frequent repairs: Could signal deteriorating protection that needs full replacement.

During a roof replacement, your contractor will inspect and replace old underlayment to restore full protection.

How Climate Affects Underlayment Choice

The Midwest’s variable climate makes underlayment selection even more critical. In Ankeny and surrounding areas, you need materials that handle moisture, wind, and fluctuating temperatures.

Cold Weather Performance

Rubberized asphalt is ideal for winter resistance, as it prevents ice dams and seals nail penetrations.

Hot Weather Performance

Synthetic underlayment resists warping and maintains integrity under prolonged sun exposure.

A balanced combination of materials—like synthetic for general coverage and rubberized asphalt in vulnerable spots—often delivers the best year-round protection.

Why Professional Installation Matters

Even top-quality underlayment can fail if installed incorrectly. Professional roofing contractors understand how to layer materials, overlap seams, and secure edges to prevent leaks.

They also assess your attic ventilation and insulation to ensure the entire roofing system performs efficiently.

Hiring a trusted local roofer in Ankeny and surrounding areas ensures you receive expert guidance, proper installation, and long-lasting results.

Trust Heartland for Your Roofing Needs

Finding the best roof underlayment for asphalt shingles doesn’t have to be confusing. By understanding the different materials, evaluating your climate, and working with skilled professionals, you can protect your home for decades.

Heartland proudly serves homeowners in Ankeny and surrounding areas with high-quality roofing solutions built to last. Whether you’re upgrading your shingles or replacing your underlayment, our team is here to help.

Contact Heartland today to schedule your free roofing estimate and ensure your home stays safe, dry, and energy-efficient all year long.