Synthetic Vs Felt Underlayment: Which One Should You Choose?
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Synthetic Vs Felt Underlayment: Which One Should You Choose?
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Synthetic Vs Felt Underlayment: Which One Should You Choose?

Posted on September 19, 2022

Estimated Reading Time : 4 Min.

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Synthetic Vs Felt Underlayment: Which One Should You Choose?

Are you getting a new roof? If the answer is yes, researching different roof components is a great place to start. If you are looking up synthetic vs felt underlayment, it is possible to find different views that can often seem confusing. So to help, our roofing experts have explained this topic in detail.

This article covers how synthetic and felt underlayments differ from each other, and which one is better. After that, you can confidently discuss your options with a local roofing contractor.

We will start by giving an overview of underlayments to make sure we are on the same page.

An Overview Of Roofing Underlayment

When asphalt shingles first came into use, people noticed that the rubbing of wooden beams and asphalt resulted in the faster deterioration of the shingles. That’s when the experts developed roofing underlayments.

Underlayment aids in a longer life span of your roof by shielding shingles and sheathing from premature wear and tear. Today, there are advanced underlayments that also offer protection against moisture damage, water leaks, ice dams, and pest infestation. You can also learn more from our blog: why you need a roof underlayment.

The most popular types of underlays are felt and synthetic. Felt is the traditional one, while synthetic underlayments are relatively advanced.

To explain synthetic vs felt underlayment, we will first compare their chemical composition. This will help you understand their attributes more clearly to take your pick.

What Is Felt Underlayment?

Felt underlays have been around for decades. You may also know this underlayment as felt paper or roofing felt. It is a mix of recyclable materials, including corrugated paper and saturated asphalt. Some manufacturers and roofing contractors reinforce felt with cellulose, sawdust, or fiberglass mats for added strength and protection.

What Is Synthetic Underlayment?

Almost 20 years back, researchers developed synthetic underlays that are weathertight and tear-resistant. This is the latest technology that most roofing contractors suggest these days. Synthetic underlayments are made of laminated polymers that are waterproof, sturdy, and durable.

When we discuss synthetic vs felt underlayment, one can certainly be better than the other. It mainly depends on the shingles, roof size, and the local climate. Below are seven factors that separate synthetic underlayment from felt.

Synthetic Vs Felt Underlayment: Which One Is Better?

Generally, homeowners want a product that has a good reputation at a good price. However, many more crucial factors make the underlayment cost-effective for you.

Resistance Power

Felt enhances the deck’s stiffness as it can handle hailstones, debris, and other impacts well. However, the cellulose in felt is prone to mold and moisture damage since it is an organic substance. Synthetic underlayments are highly resistant to water, fire, and wind. Since plastics don’t absorb moisture, synthetic underlayment remains free of wrinkles, mold, and algae.

Bonus Tip: Rubberized underlayment is the best choice for hail-prone areas, but it costs more than felt and synthetic underlayments.


Synthetic underlayments have incredible elasticity and they are resistant to tears. They can stay strong during extremely hot and cold temperatures without warping or releasing chemicals. On the other hand, severe heat or cold can cause a felt underlayment to absorb moisture and eventually crack apart.


When discussing synthetic vs felt underlayments, durability matters a lot. Your underlayment must have a lifespan as long as other roof components. Synthetic underlayments generally last longer than felt due to their resistance powers and flexibility. When your shingles are in good shape, a synthetic underlay can stay strong for 50 years and felt for 30 years. If you are using a felt underlayment, ensure that it is not exposed for long and the shingles are installed within one day. Otherwise, felt may develop cracks due to UV exposure.


While both underlays come in mats and rolls, synthetic underlayments are longer. When the rolls are long enough, you don’t need so many of them. Moreover, installing them is more manageable and this can possibly reduce the installation cost by a few dollars. Felt comes in smaller sizes, so you need more rolls and mats, and they require more time and labor to install.


Synthetic underlayments usually come in a peel-and-stick form, which is ideal for installation. It also has a non-slippery surface, ensuring the safety of the installation team on your roof which is vital to any roofing work. Synthetic underlayments also offer excellent support to the ice and water shield around the chimney, vents, and flashing.

Moving on to felt, this underlayment is installed using nails. Some homeowners may not prefer it since it requires drilling holes in the roof sheathing, which doesn’t sound pleasant. Moreover, its slippery surface is a huge concern during the roof installation process.


There are many different types of felt and synthetic underlayments. The primary cost depends on the quality and warranty of the underlayments, which depends on the manufacturer. Generally, felt underlayments have more affordable price tags, but the countless advantages of synthetic underlayments make them more cost-effective in the long run.

The final cost of your roof replacement project includes everything from start to finish. If you are looking for someone to help you choose suitable roofing materials, you can count on us.

We Can Help You Choose The Right Roofing Materials

All Around Roofing, Siding & Gutters is your friendly neighborhood company in Dayton, OH. We understand the importance of having a roof that can protect your home without fail for years. At All Around Roofing, Siding & Gutters, we are proud to have the most reliable and knowledgeable roofing specialists in the area. You can trust our team to guide you at every step of the way. Our experts have been helping the community build sturdy and beautiful homes for years!

We hope you find this article helpful, and you are now able to make a more educated choice for your home. If you want to learn more about underlayments, and other roofing components, call us at (937) 902-2839 for a free consultation.

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