Felt Underlayment vs. Synthetic Underlayment: Which is Better?

Felt Underlayment vs. Synthetic Underlayment: Which Is Better for Your Roof?

When it comes to roofing materials, one of the most important decisions homeowners and contractors need to make is selecting the right underlayment for the job. Roofing underlayment serves as a secondary barrier to protect your home from water, moisture, and extreme weather conditions. It is placed directly under the shingles, serving as a vital part of the roof’s structure.

There are two primary types of roofing underlayment materials that you may encounter during a roofing project: felt underlayment and synthetic underlayment. Both materials offer distinct advantages and disadvantages, and the choice between them can influence the longevity and overall effectiveness of your roof. As an Owens Corning Preferred Contractor based in Youngstown, Ohio, S&K Construction And Remodeling LLC has experience with both types of materials, and in this blog, we’ll explore the differences, benefits, and considerations of felt underlayment vs. synthetic underlayment, helping you make an informed decision for your roofing needs.

What is Roofing Underlayment?

Roofing underlayment is a water-resistant or waterproof material installed directly beneath the shingles of a roof. It provides an additional layer of protection against rain, snow, ice, and other weather elements that can cause leaks or damage. Underlayment plays a significant role in protecting the roof deck and preventing water infiltration in the event of a shingle failure or damage. It also serves as a protective layer between the roof deck and the shingles, ensuring that the roof’s performance is not compromised over time.

Felt Underlayment: A Traditional Choice

Felt underlayment, also known as tar paper or roofing felt, has been a staple in the roofing industry for many decades. Made from a fibrous material that is saturated with asphalt, felt underlayment provides a reliable moisture barrier that has been used in residential and commercial roofing for years.

Pros of Felt Underlayment

1. Cost-Effective: Felt underlayment is generally less expensive than synthetic underlayment. If you’re on a budget and need to keep roofing costs low, felt may be a more affordable option.
2. Durability: Felt underlayment has a long track record of performance. When installed properly, it can provide many years of protection.
3. Breathability: Felt is a more breathable material, allowing air to flow through the underlayment. This can help prevent mold and mildew growth in certain climates, especially in homes with ventilation concerns.
4. Proven Track Record: With over a century of use in the roofing industry, felt underlayment has a proven history of reliability and is trusted by roofing professionals worldwide.
5. Simple Installation: Felt underlayment is relatively easy to install, which can save on labor costs. It’s available in rolls that can be unrolled across the roof deck, making it suitable for both professional contractors and DIY enthusiasts.

Cons of Felt Underlayment

1. Heavy: Felt underlayment is heavier compared to synthetic options, which can make it harder to handle and install. This can also add to the overall weight of the roof structure.
2. Susceptible to Damage: Felt is vulnerable to tearing and damage during installation, and it can degrade over time if exposed to the elements. If it gets wet before the shingles are installed, it can lose its protective capabilities.
3. Limited Longevity: While felt is durable, it has a shorter lifespan compared to synthetic materials. Over time, felt can deteriorate due to prolonged exposure to moisture and UV rays, which may compromise the roof’s performance.
4. Absorption of Moisture: Felt can absorb moisture, which could lead to issues like mold growth, rot, or an overall reduction in its protective abilities. This is especially true in areas with high humidity or consistent rain.
5. Inconsistent Performance: Because felt underlayment is made from natural materials, its performance can vary depending on the quality of the product. Some lower-grade felt underlayment may not be as durable or effective in preventing leaks.

Synthetic Underlayment: The Modern Alternative

Synthetic underlayment has become a popular choice in recent years due to its advanced technology and numerous performance benefits. Made from polymers such as polypropylene or polyethylene, synthetic underlayment is designed to outperform traditional felt underlayment in many aspects.

Pros of Synthetic Underlayment

1. Superior Durability: Synthetic underlayment is much stronger and more durable than felt. It is resistant to tearing, punctures, and abrasion, making it an excellent choice for areas with harsh weather conditions.
2. Longer Lifespan: Synthetic underlayment is designed to last longer than felt. It can withstand exposure to UV rays and moisture for many years without deteriorating, making it a great option for long-term protection.
3. Lightweight: Synthetic underlayment is lighter than felt, making it easier to handle and install. This can reduce labor costs and improve installation efficiency.
4. Moisture Resistance: Unlike felt, synthetic underlayment does not absorb moisture. It acts as a true barrier against water infiltration, which helps protect the roof deck and other structural components.
5. Better Performance in Extreme Weather: Synthetic underlayment performs well in extreme weather conditions, including heavy rain, snow, and high winds. It remains intact and functional even in the most challenging environments.
6. Fire Resistance: Many synthetic underlayments are treated with fire-resistant chemicals, providing an added layer of protection for the roof. This is particularly beneficial in regions that are prone to wildfires or dry conditions.
7. Slip Resistance: Synthetic underlayment is often designed with a textured surface that makes it safer for roofers to walk on during installation. This can reduce the risk of accidents and improve overall safety on the job site.
8. Warranties: Many manufacturers of synthetic underlayment offer extended warranties, sometimes up to 50 years. These warranties provide peace of mind, knowing that the material is covered for the long term.

Cons of Synthetic Underlayment

1. Higher Cost: Synthetic underlayment tends to be more expensive than felt underlayment. While the initial cost may be higher, the extended lifespan and superior performance often make it a worthwhile investment in the long run.
2. Installation Complexity: While synthetic underlayment is lighter than felt, it may require special handling during installation due to its slick surface. Some installers may find it more challenging to work with, especially if they are not familiar with synthetic materials.
3. Heat Sensitivity: Some types of synthetic underlayment may be sensitive to heat and could become brittle when exposed to high temperatures. It’s essential to choose a synthetic underlayment designed for your local climate.

Felt Underlayment vs. Synthetic Underlayment: Key Differences

Let’s break down the key differences between felt underlayment and synthetic underlayment, comparing their performance across several important factors:

Factor	Felt Underlayment	Synthetic Underlayment
Cost	More affordable	Higher initial cost
Durability	Less durable, more prone to damage over time	Extremely durable, resistant to tears and punctures
Lifespan	Shorter lifespan (10-15 years)	Longer lifespan (20-50 years)
Weight	Heavier, more difficult to handle	Lighter, easier to handle and install
Moisture Resistance	Can absorb moisture, leading to mold and decay	Waterproof, does not absorb moisture
UV Resistance	Can degrade with UV exposure	UV-resistant, lasts longer in direct sunlight
Fire Resistance	Limited fire resistance	Often treated with fire-resistant chemicals
Slip Resistance	Less slip-resistant	Often designed with textured surface for better grip
Environmental Impact	Less environmentally friendly (natural material)	More eco-friendly (often made from recycled materials)
Warranties	Limited or no warranties	Extended warranties available, up to 50 years

Which Underlayment is Right for You?

The decision to choose between felt underlayment and synthetic underlayment depends on several factors, including budget, climate, and the long-term goals for your roof.

When to Choose Felt Underlayment

Felt underlayment may be a better choice if:

• You are working with a tighter budget and need a more affordable option.
• You live in a moderate climate with mild weather conditions that don’t see extreme rain, snow, or high winds.
• You are working on a historical home where traditional materials may be preferred.

When to Choose Synthetic Underlayment

Synthetic underlayment is ideal if:

• You are willing to invest in a higher upfront cost for better long-term protection.
• You live in an area with harsh weather conditions, such as heavy rain, snow, or high winds.
• You want a lighter, more durable material that will last longer and resist moisture and UV damage.
• You are interested in fire-resistant materials for added protection.

Conclusion

In the debate between felt underlayment and synthetic underlayment, both options offer significant benefits. Felt underlayment remains a trusted, cost-effective option for many roofing projects, but synthetic underlayment is often the superior choice for homeowners who seek enhanced durability, moisture resistance, and long-term protection. For residents in Northeast Ohio, where we experience a wide range of weather conditions, synthetic underlayment may be particularly beneficial in ensuring your roof’s longevity and performance.

At S&K Construction and Remodeling LLC, we offer a wide range of roofing solutions tailored to the needs of homeowners in Youngstown, Cleveland, Medina, and surrounding areas. Whether you are interested in upgrading to synthetic underlayment or maintaining your existing roof with felt underlayment, our team is here to help you choose the best materials and ensure a quality installation.

If you’re ready to take the next step in protecting your home with high-quality roofing materials, reach out to S&K Construction and Remodeling LLC today for a consultation. We’ll walk you through the options and help you make an informed decision that will provide lasting value for your home.