Old-Style Felt vs. New Synthetic Underlayment: Which is Best for Your Roof?

Roofing technology has come a long way over the years, and one area where advancements have been particularly significant is in roofing underlayment. Traditionally, builders used asphalt-saturated felt, often referred to as “tar paper,” as the go-to underlayment material. However, synthetic underlayments have become the modern standard, offering significant advantages.

Whether you’re considering a new roof or replacing an old one, understanding the differences between traditional felt and synthetic underlayment can help you make an informed decision. Let’s dive into the pros and cons of each.

What is Roofing Underlayment?

Roofing underlayment is a protective layer installed between the roof deck and the shingles. Its primary purpose is to provide an additional barrier against water infiltration, acting as a safeguard in case shingles are damaged or improperly installed.

Traditional Felt Underlayment

Felt underlayment has been used for decades and is typically made of a combination of organic or fiberglass base sheets saturated with asphalt. It comes in two common grades: 15-pound and 30-pound felt, with the latter being thicker and more durable.

Advantages of Felt Underlayment:

1. Affordable: Felt is one of the most cost-effective roofing underlayments, making it appealing for budget-conscious homeowners.

2. Time-Tested: Having been around for decades, felt is a trusted and familiar option for many contractors.

3. Readily Available: It’s widely available at most hardware stores and supply centers.

Disadvantages of Felt Underlayment:

1. Less Durable: Felt is prone to tearing, especially during installation or in high winds. This can compromise its effectiveness.

2. Absorbs Moisture: Felt can absorb water, which may cause it to wrinkle or degrade over time.

3. Heavy: Compared to synthetic options, felt is heavier, making it harder to handle and install.

4. Temperature Sensitivity: Extreme heat can cause felt to dry out and crack, reducing its lifespan.

5. Limited Lifespan: Felt underlayment tends to degrade more quickly than synthetic materials, especially under prolonged exposure to the elements.

Synthetic Underlayment

Synthetic underlayment is a newer innovation made from woven or spun polyethylene or polypropylene. It is designed to outperform traditional felt in nearly every category.

Advantages of Synthetic Underlayment:

1. Durability: Synthetic underlayments are much stronger and more resistant to tearing, even under challenging conditions like strong winds or during installation.

2. Moisture Resistance: Unlike felt, synthetic materials do not absorb water. This makes them ideal for roofs that may remain exposed during construction.

3. Lightweight: Synthetic underlayments are lighter and easier to handle, making installation faster and safer.

4. UV Resistance: Most synthetic products can withstand prolonged UV exposure, giving contractors more flexibility during installation without risking degradation.

5. Longer Lifespan: Synthetic materials are designed to last longer, providing better protection for your home over time.

6. Slip Resistance: Many synthetic products have a textured surface, which provides better traction for roofers, enhancing safety during installation.

Disadvantages of Synthetic Underlayment:

1. Higher Cost: Synthetic underlayments are generally more expensive upfront compared to traditional felt.

2. Special Installation Requirements: Some synthetic underlayments may require specific fasteners or installation techniques, which could add to labor costs.

Key Differences Between Felt and Synthetic Underlayment

Which Underlayment is Right for Your Roof?

The choice between felt and synthetic underlayment depends on several factors, including your budget, the complexity of your roofing project, and your long-term goals.

• Budget-Friendly Projects: If cost is your primary concern, traditional felt may be a suitable option, especially for smaller projects or temporary fixes.

• Long-Term Durability: For homeowners looking to invest in a roofing system that provides superior protection and longevity, synthetic underlayment is the clear winner.

Why Midwest Exterior Recommends Synthetic Underlayment

At Midwest Exterior, we prioritize quality and long-term performance for our customers in Derby and the surrounding Kansas areas. That’s why we often recommend synthetic underlayment for roofing projects. While it may have a higher upfront cost, the durability, moisture resistance, and extended lifespan make it a smarter investment in the long run.

Whether you’re replacing a few shingles or installing an entirely new roof, we’ll guide you through the process and ensure you have the right materials for your home.

Contact Midwest Exterior Today

Need help deciding which underlayment is right for your roof? Contact Midwest Exterior for a free consultation. We’re here to provide expert advice, high-quality materials, and exceptional craftsmanship to keep your home protected for years to come.