Synthetic Underlayment vs. Roofing Felt: Which Is Better for Georgia Homes?

When you look at a finished roof, you see shingles.

What you don't see is one of the most important layers protecting your home: roof underlayment.

Underlayment sits between your roof decking and shingles. While shingles provide the primary protection against rain and weather, underlayment adds another protective layer underneath the roofing system.

If you're replacing your roof in McDonough, you'll likely hear about two common options: traditional roofing felt and synthetic underlayment.

So what's the difference, and which one makes more sense for a Georgia home? Let's break it down.

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What Is Roof Underlayment?

Once the old shingles are removed during a roof replacement, the contractor can inspect the wood decking underneath.

After necessary decking repairs are completed, underlayment is installed over the roof deck before the new shingles go on. Its purpose is to provide an additional layer of protection between the wood decking and the exterior roofing material.

A complete asphalt roofing system may include:

• Roof decking
• Underlayment
• Drip edge
• Starter shingles
• Field shingles
• Flashing
• Ridge cap
• Ventilation components

That's why a roof replacement should be viewed as a complete system, not simply new shingles.

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What Is Traditional Roofing Felt?

Roofing felt, sometimes called tar paper, has been used in residential roofing for decades.

It's generally made from a base material saturated or coated with asphalt. Common options include #15 and #30 felt.

Advantages of Roofing Felt

Traditional felt has a few benefits:

• Lower material cost
• Long history of use
• Widely available
• Familiar to roofing contractors

For many years, it was the standard underlayment used underneath asphalt shingles.

What Are the Drawbacks of Roofing Felt?

Felt works, but newer products offer some advantages. Traditional felt can be:

• Heavier to handle
• Easier to tear during installation
• More vulnerable if exposed to weather
• More difficult to walk on depending on conditions

If felt becomes damaged before the shingles are installed, those areas need to be addressed before the roofing system is completed.

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What Is Synthetic Roof Underlayment?

Synthetic underlayment is a newer alternative made from engineered materials rather than traditional asphalt-saturated felt.

It's designed specifically to provide a durable protective layer underneath the finished roofing material. Synthetic products vary by manufacturer, but they've become increasingly common on residential roof replacements.

Advantages of Synthetic Underlayment

There are several reasons contractors and homeowners choose synthetic underlayment.

It's Lightweight — Synthetic rolls can cover a large amount of roof area while remaining relatively lightweight. This makes installation easier and more efficient.

It's Tear Resistant — Synthetic underlayment generally offers strong resistance to tearing during installation. That's especially useful when crews are walking across the roof while installing shingles.

It Provides Good Traction — Many synthetic products are manufactured with textured surfaces designed to improve traction for installers.

It Handles Temporary Exposure Better — If weather interrupts a roofing project, certain synthetic products can tolerate temporary exposure better than traditional felt. The exact exposure limits depend on the manufacturer.

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Is Synthetic Underlayment Waterproof?

This is an important distinction.

Standard synthetic underlayment should not automatically be confused with a waterproof membrane. Your shingles remain the primary weather-shedding surface of an asphalt roof.

For areas especially vulnerable to water intrusion, contractors may use a different product commonly called ice-and-water shield or a self-adhering waterproof membrane.

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What Is Ice-and-Water Protection?

Ice-and-water membrane is designed to create a stronger water-resistant barrier in vulnerable areas of the roofing system.

Depending on the roof design and applicable installation requirements, it may be used around areas such as:

• Valleys
• Roof penetrations
• Chimneys
• Certain flashing areas
• Other vulnerable transitions

Despite the name, these membranes aren't useful only in northern climates. Heavy Georgia rain can push a roofing system hard, particularly around valleys and penetrations.

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Which Is Better: Synthetic Underlayment or Felt?

For many modern roof replacements, synthetic underlayment is an excellent choice because of its durability, lighter weight, tear resistance, and installation characteristics.

That doesn't mean every synthetic product is automatically better than every felt product. Product quality and proper installation still matter.

When comparing estimates, ask exactly which underlayment is included instead of accepting a proposal that simply says "install underlayment."

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Does Underlayment Make a Big Difference in Price?

Compared with the total cost of a roof replacement, upgrading the underlayment may represent a relatively small portion of the project.

Pricing depends on:

• Roof size
• Product selected
• Roof complexity
• Installation requirements

The bigger question is what you're getting for the overall price.

If you're researching replacement costs, read: How Much Value Does a New Roof Add to Your Home in McDonough, GA?

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What Happens to the Underlayment During a Roof Replacement?

On a complete tear-off, the existing roofing materials are removed so the contractor can evaluate what's underneath.

This is important because damaged decking shouldn't simply be covered up. Once the deck is ready, the new roofing system can be installed according to the project's specifications and manufacturer requirements.

This is one reason we generally prefer evaluating the complete roofing system rather than simply covering old shingles. Read: Can You Install a New Roof Over Old Shingles?

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Don't Choose a Roof Based Only on the Shingle Brand

It's easy to compare roofing estimates by looking at the shingle. But two contractors could use the exact same shingle and install very different roofing systems underneath it.

When comparing proposals, look at:

• Shingle manufacturer and product
• Underlayment
• Starter shingles
• Ridge cap
• Flashing
• Drip edge
• Ventilation
• Pipe boots
• Decking replacement terms
• Workmanship warranty

Those details can help explain why two roofing estimates aren't always apples-to-apples.

Learn more: Roof Warranties Explained: What McDonough Homeowners Should Know

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Ask What's Going Under Your New Roof

A new roof is expected to protect your home for years.

It's worth knowing what's underneath the shingles before everything gets covered up. A good roofing contractor should be able to explain the materials being installed and why they're being used.

If you're comparing roof replacement estimates, don't be afraid to ask questions.

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Request a Roof Replacement Estimate in McDonough

If your roof is aging or you're considering replacement, Stress Free Remodeling Co. can inspect your existing roofing system and walk you through your options.

We'll explain the materials included in your estimate so you understand what you're buying — not just the final price.

Request Your Free Roof Replacement Estimate

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Proudly Serving McDonough & Metro Atlanta

Stress Free Remodeling Co. proudly serves homeowners throughout:

• McDonough
• Stockbridge
• Locust Grove
• Hampton
• Henry County
• Metro Atlanta

Whether you need a roof inspection, repair, or complete replacement, we're here to help you make an informed decision about your home.