What Is Roof Felt & How Long It Lasts?

When it comes to protecting your roof—and your home—roof felt plays a crucial role. This unsung hero serves as an additional barrier against moisture, helping to keep your home safe and dry. But how long does roof felt actually last? And what factors can impact its lifespan? If you’ve been wondering about the durability of your roof felt, you’ve come to the right place.

In this guide, we’ll break down everything you need to know about roof felt, from:

• Its purpose
• Installation
• Average lifespan
• Tips for prolonging its durability

Whether you’re planning a roof replacement or simply want to understand more about your existing roof, we’ve got you covered.

What Is Roof Felt?

Roof felt, also known as roofing underlayment or tar paper, is a protective layer made from a combination of natural materials like wood pulp and synthetic materials like fiberglass. This layer is typically installed between the roof deck (the wooden or plywood base of your roof) and your roof’s outer covering, like shingles, tiles, or metal panels.

Roof felt is often saturated with asphalt or bitumen, making it water-resistant and more durable. Its primary function is to serve as an additional layer of defense against water, wind, and other weather-related elements.

Why Is Roof Felt Important?

Roof felt may not be visible from the outside, but its role is essential to the health and longevity of your roof. Here’s why it’s so important:

• Protects Against Water Damage: Roof felt provides an extra barrier to prevent water from infiltrating the home if the outer layer of the roof is damaged or compromised.
• Acts as a Moisture Barrier: It helps to reduce the risk of moisture getting trapped in the roof deck, which can lead to rot or structural issues.
• Adds Wind Protection: The underlayment creates an extra layer of protection against strong winds that can pry shingles loose.
• Provides a Safety Net: During the roof installation process, felt offers temporary protection should bad weather strike before the main layer of shingles or tiles is installed.

How Long Does Roof Felt Last?

Roof felt is durable, but like any material, it doesn’t last forever. The lifespan of roof felt depends on several factors, including the quality of the material, the type of roof felt, installation quality, and environmental conditions.

Average Lifespan of Roof Felt

• Traditional Roof Felt (20-30 lbs): Standard felt underlayment typically lasts between 15 to 20 years when it is correctly installed and well-maintained. However, some may degrade sooner in harsh climates.
• Synthetic Roof Felt: High-quality synthetic roof felts can last much longer—up to 25 to 40 years or more, depending on the brand and application. These types are becoming increasingly common due to their superior durability and resistance to wear and tear.

Factors That Affect Roof Felt Lifespan

Several variables can influence how long your roof felt will last:

1. Climate and Weather Exposure: Extreme weather conditions, such as heavy rain, snow, high winds, or scorching sun, can degrade roof felt faster.
2. Type of Roofing Material: The kind of outer covering on your roof—such as asphalt shingles, clay tiles, or slate—can impact how well the felt performs.
3. Quality of Installation: Poorly installed roof felt may not adhere properly or may wrinkle, which significantly reduces its effectiveness and longevity.
4. Ventilation: Poor roof ventilation can trap moisture and heat, shortening the lifespan of the roof felt.
5. Roof Pitch: The slope of your roof affects water runoff. Flatter roofs hold more water, which can wear down roof felt faster.

Signs It’s Time to Replace Roof Felt

While roof felt is built to last, there are clear signs that it might be time for a replacement. Keep an eye out for these red flags:

• Leaks Inside Your Home: If you’re noticing water stains or leaks indoors, there could be damage to the roof felt.
• Missing or Damaged Shingles: Missing shingles can expose roof felt to the elements, leading to faster wear and tear.
• Visible Wrinkles or Tears in the Felt: During an inspection, if you or a contractor notice tears or wrinkles in the felt, it may no longer provide adequate protection.
• Mold or Mildew Growth: Mold and mildew on your roof or inside your attic could indicate trapped moisture, meaning the roof felt isn’t functioning properly.
• Age of the Roof: If your roof is nearing the end of its intended lifespan (20+ years for traditional felt), it’s time to start planning for replacement.

How to Extend the Life of Your Roof Felt: 6 Popular Tips

Proper installation and regular maintenance are key to getting the most out of your roof felt. Here are some practical tips to help you extend its lifespan:

1. Schedule Regular Roof Inspections

A professional roof inspection once or twice a year can catch small problems before they become major issues. Inspections are especially important after severe weather events.

2. Ensure Proper Roof Ventilation

Adequate airflow in your attic can prevent heat and moisture buildup, which can damage both the roof deck and the roof felt.

3. Fix Damage Quickly

If shingles are missing or damaged, have them replaced as soon as possible to protect the roof felt beneath.

4. Use High-Quality Roofing Materials

Investing in top-quality felt and roofing materials during installation can significantly impact how long your roof felt lasts. Synthetic options tend to offer the best durability.

5. Keep Your Roof Clean

Remove debris like leaves, branches, and moss from your roof regularly. This prevents moisture retention that can lead to premature wear of the felt.

6. Partner with Professional Roofers

Ensure your roof felt and overall roofing installation is done by reputable contractors. Quality workmanship will enhance the performance and lifespan of your roof.

Roof Felt vs. Synthetic Underlayment—Which One is Better?

Recently, synthetic underlayment has become a popular alternative to traditional roof felt. If you’re considering your options, here’s a quick comparison:

Traditional Roof Felt

• Pros: Affordable, readily available, and time-tested.
• Cons: Less durable, absorbs moisture, and can rip or tear more easily during installation.
• Best For: Budget-conscious homeowners or homes in more moderate climates.

Synthetic Roof Felt

• Pros: More durable, lightweight, and resistant to water, UV radiation, and tearing.
• Cons: Higher upfront cost than traditional felt.
• Best For: Homes in extreme climates or those looking for longer-lasting protection.

Why Professional Installation Matters

While DIY roofing projects might seem tempting, improper installation of roof felt can compromise its performance and longevity. By working with experienced professionals like Roof Medic, you ensure:

• Proper alignment and adhesion of the felt to prevent wrinkles or overlap issues.
• Use of high-quality materials suited to your climate and roofing structure.
• The peace of mind of knowing your roof is built to last.

The Roof Medic Advantage

At Roof Medic, we understand how vital it is to have a functional and durable roofing system. That’s why our expert team goes beyond just fixing what’s broken. We ensure that every layer of your roof, including roof felt, meets the highest quality standards.

Why Choose Us?

• Experienced and certified roofing professionals.
• Honest assessments and upfront pricing.
• Top-quality materials for every project.
• Comprehensive warranties for peace of mind.

If you’re concerned about the condition of your existing roof felt or are planning a roof replacement, schedule a free consultation with Roof Medic today. We’ll assess your roof’s condition and recommend the best solution for your home.