Synthetic vs. Felt Roofing Underlayment: Understanding the Pros and Cons

 When it comes to choosing roofing underlayment, the debate often centers around synthetic and felt materials. Each option has unique advantages and disadvantages, and the choice largely depends on factors such as budget, climate, and project requirements. In this article, we’ll explore the key differences, benefits, and limitations of both synthetic and felt roofing underlayments to help you make an informed decision.

What Is Roofing Underlayment?

Roofing underlayment is a protective layer installed between the roof deck and the shingles. It acts as a secondary barrier against water, ensuring that the roof remains durable and weather-resistant. Two of the most common types of underlayment are synthetic and felt, each with its own distinct properties and applications.

Understanding Synthetic Roofing Underlayment

Synthetic roofing underlayment is made from a combination of polypropylene or polyethylene, resulting in a lightweight and durable material. It is a newer innovation in roofing technology, designed to address some of the limitations found in traditional felt underlayment.

One of the main advantages of synthetic underlayment is its exceptional durability. It is resistant to tearing, UV exposure, and moisture, making it ideal for areas with extreme weather conditions. Its lightweight nature also simplifies installation, reducing the physical strain on roofing contractors and speeding up the process. Additionally, synthetic underlayment is highly resistant to mold and mildew, which enhances its longevity and performance.

However, synthetic underlayment tends to be more expensive than felt. For homeowners and contractors working with tight budgets, this cost difference can be a significant factor. Furthermore, while synthetic materials offer excellent performance, their environmental impact is a consideration, as they are not as easily recyclable as natural materials.

Exploring Felt Roofing Underlayment

Felt roofing underlayment, also known as tar paper, has been a traditional choice for decades. Made from a combination of asphalt and either organic or fiberglass material, felt is valued for its affordability and accessibility.

The primary benefit of felt underlayment is its low cost. It provides a reliable barrier against water and is sufficient for many standard roofing applications. Felt is also widely available, making it a convenient option for projects with limited time or resources.

Despite its affordability, felt underlayment has several limitations. It is prone to tearing, especially during installation or when exposed to high winds. Its water resistance diminishes if it remains wet for prolonged periods, which can compromise its effectiveness. Additionally, felt is heavier than synthetic options, which can make installation more labor-intensive. Over time, it may also become brittle, reducing its lifespan and performance.

Key Considerations for Choosing Between Synthetic and Felt

The choice between synthetic and felt roofing underlayment depends on several factors. If durability, weather resistance, and longevity are top priorities, synthetic underlayment may be the better option despite its higher cost. On the other hand, for budget-conscious projects or those with simpler requirements, felt underlayment can provide an adequate and cost-effective solution.

Climate also plays a significant role in the decision. Synthetic underlayment performs better in areas with heavy rainfall, strong winds, or extreme temperatures due to its superior resistance to moisture and tearing. Conversely, felt may suffice in milder climates where these conditions are less prevalent.

Final Thoughts

Choosing the right roofing underlayment is a critical step in ensuring the longevity and performance of your roof. Synthetic and felt underlayments each offer distinct benefits and drawbacks, and understanding these differences is key to making the best choice for your needs. By considering factors such as budget, climate, and project specifications, you can select an underlayment that provides optimal protection and value for your roofing system.