what is the purpose of roofing felt

Understanding Roofing Felt’s Essential Purpose

Did you know that roofing felt serves as a vital protective layer for your roof, guarding it against moisture damage and leaks?

Roofing felt, also known as roofing underlayment or tar paper, may not be the most glamorous part of a roofing system, but its benefits are undeniable. It acts as a shield between the roof deck and the shingles, providing crucial protection against the elements.

Key Takeaways:

  • Roofing felt is a protective layer that prevents moisture damage and leaks.
  • It acts as a barrier between the roof deck and shingles.
  • Roofing felt provides additional water repellency and backup protection.
  • It improves the aesthetics and uniformity of the roof.
  • Roofing felt is important for compliance with fire ratings and preventing wood resin stains.

What is Roofing Felt and its Composition?

Roofing felt, also called roofing tar paper or roll roofing, is a crucial component of a roofing system. It is made of a base material, either natural, such as wood cellulose, or synthetic, like fiberglass or polyester. This base material is then coated or saturated with a protective coating, typically bitumen (asphalt). The composition of roofing felt allows it to repel water while still allowing the roof to breathe, making it an indispensable barrier between the roof deck and shingles.

Roofing felt serves multiple functions, primarily providing additional protection against moisture and weather elements. It acts as a safeguard against leaks and water infiltrations, ensuring the longevity and integrity of the roof. The protective coating on the felt helps repel water and prevents it from seeping through the roof, keeping the underlying structure dry. Additionally, the roofing felt provides an extra layer of defense against extreme weather conditions, such as heavy rain or snow.

The composition of roofing felt also plays a role in its durability and performance. The use of natural or synthetic materials affects the strength and longevity of the felt. Natural materials like wood cellulose offer excellent insulation properties, while synthetic materials like fiberglass or polyester provide enhanced strength and resistance to tears and punctures. The protective coating of bitumen helps seal the felt and ensures its ability to withstand exposure to various weather elements.

Overall, roofing felt is an essential component of a roofing system, and its composition and design contribute to its numerous functions and benefits. The combination of base materials and protective coating provides the necessary support and protection to ensure the longevity and performance of the roof.

The Importance of Roofing Felt as an Underlayment

Roofing felt serves as an underlayment for the roof, providing essential benefits and protection. It holds great importance in ensuring the longevity and integrity of your roof.

  • Preventing water infiltration: One of the main advantages of roofing underlayment is its ability to prevent water infiltration. By creating an additional barrier between the roof deck and the shingles, roofing felt helps protect your home from moisture damage, leaks, and potential mold growth.
  • Backup protection: In the unfortunate event of ice or water damage, roofing felt acts as a backup protection layer. It provides an extra level of water resistance, ensuring that any moisture that penetrates the shingles has an additional barrier to overcome before reaching the roof deck.
  • Extra weather protection: Roofing felt enhances the overall weather resistance of your roof. It helps shield the roof deck from harsh weather elements such as wind, rain, and snow, reducing the risk of damage and increasing the lifespan of your roofing system.
  • Improved look and uniformity: The uniformity provided by roofing felt gives your roof a polished appearance. It creates a smooth surface for the shingles, enhancing the overall aesthetic appeal of your home.
  • Prevention of wood resin stains: Roofing felt prevents wood resin from seeping through the shingles and staining the roof deck. This helps maintain the integrity of the roof’s structure and prevents unsightly discoloration.

Roofing felt is an invaluable component of your roofing system, fulfilling crucial roles in protecting your home from moisture damage, leaks, and other weather-related issues. It is important to invest in quality roofing underlayment to ensure the full benefits and protection it offers.

To illustrate the importance of roofing felt, take a look at the following comparison table:

Roofing Felt No Roofing Felt
Water Resistance Provides an additional barrier against water infiltration Increased risk of moisture damage and leaks
Backup Protection Acts as a secondary defense against ice and water damage Minimal protection in case of water intrusion
Weather Protection Enhances overall weather resistance Greater susceptibility to weather-related damage
Appearance Creates a uniform and polished look Uneven surface and less appealing appearance
Wood Resin Stains Prevents wood resin stains on the roof deck Risk of unsightly discoloration

Importance of Roofing Felt Installation

By understanding and recognizing the advantages and importance of roofing felt as an underlayment, you can make informed decisions about your roofing system and ensure the long-term protection of your home.

Choosing the Right Weight and Amount of Roofing Felt

When it comes to selecting roofing felt for your project, it’s important to consider the weight and amount that will best suit your needs. Traditional options include 15-pound and 30-pound felts, with the weight referring to the amount in pounds per hundred square feet.

The 15-pound roofing felt is ideal for lighter duty projects and steeper pitched roofs. It provides adequate protection and is more cost-effective for projects where heavy-duty protection is not necessary. On the other hand, the 30-pound felt offers increased durability and resistance to severe weather conditions, making it suitable for projects that require extra protection.

If you’re looking for an alternative to traditional roofing felt, synthetic underlayment is also available. This lightweight and durable option provides excellent protection against moisture and offers superior resistance to tearing and wrinkling. Synthetic underlayment is a popular choice for both residential and commercial roofing projects.

To determine the amount of roofing felt you need, first calculate the area of your roof in square feet. Then, divide that number by the area contained in the rolls of roofing felt you are considering. This will give you an estimate of how many rolls you will need. It’s always a good idea to have about 10% extra material to account for waste and to ensure complete coverage.

Felt Weight Benefits
15-pound – Suitable for lighter duty projects
– More cost-effective
– Ideal for steeper pitched roofs
30-pound – Offers heavy-duty protection
– Increased durability
– Resistance to severe weather conditions
Synthetic Underlayment – Lightweight and durable
– Excellent moisture protection
– Superior resistance to tearing and wrinkling

By choosing the right weight and amount of roofing felt, you can ensure that your project is protected against moisture damage, leaks, and other weather-related issues. Whether you opt for the traditional 15-pound or 30-pound felts or decide to go with the synthetic option, you can have peace of mind knowing that your roof is in good hands.

Choosing the Right Weight and Amount of Roofing Felt

Installation and Application of Roofing Felt

When it comes to installing roofing felt, there are a few important considerations to keep in mind. One of the most common questions we receive is whether to nail or staple the roofing felt in place. The answer is simple: you should use roofing nails to secure the felt to the roof decking. Nails are more reliable and provide better hold than staples, ensuring that the underlayment stays in place even under extreme weather conditions.

While there are cases where gluing roofing felt to the decking might be appropriate, it is generally not recommended. Gluing is less common and typically reserved for low-slope roof applications where adhesive is specified. For most standard residential roofs, nails are the preferred method of attachment, as they offer greater stability and durability.

It’s essential to check the manufacturer’s instructions for your specific roofing felt to determine the recommended fasteners and installation method. The manufacturer will provide guidelines based on their product’s design and intended use, ensuring proper installation for optimal performance.

Another important point to note is that you should never install shingles over roofing felt that has accumulated frost or snow. This is because the underlayment needs to be dry before shingle installation to prevent moisture-related issues. If the roofing felt is wet or frozen, it is best to wait until it is dry before proceeding with shingle installation to ensure a successful and long-lasting roof.

Installation Dos Installation Don’ts
  • Use roofing nails for secure attachment
  • Follow manufacturer’s instructions
  • Avoid using staples as they provide less stability
  • Don’t glue roofing felt unless recommended by the manufacturer

Quote from our experts:

“Correctly installing roofing felt is crucial for the overall performance and longevity of your roof. Secure it with roofing nails and avoid gluing, unless specified by the manufacturer. And always ensure the underlayment is dry before installing shingles. These simple steps will help protect your home and investment.”

can roofing felt be glued

Installing roofing felt is a critical step in the roof construction process. By following the proper installation methods and using the right fasteners, you can ensure that your roof is well-protected and durable. Remember, it’s always best to consult with a professional roofer if you have any questions or concerns about the installation process.


Roofing felt is a crucial component in protecting your roof and residence from moisture damage, leaks, and other weather-related issues. Its benefits go beyond providing additional water repellency and backup protection. Roofing felt also offers extra weather resistance and improves the overall aesthetics of your roof.

Choosing the right weight and quantity of roofing felt is essential for optimal performance. It ensures that your roof receives the right level of protection based on its specific needs. Additionally, following proper installation and application methods is crucial to achieve the best results with your roofing felt.

In conclusion, roofing felt is an essential part of any roofing system. Its numerous benefits contribute to the longevity and integrity of your roof, providing you with peace of mind and added protection for your home. If you require professional roofing services and expertise, don’t hesitate to reach out to Lynchburg Roofers at 434-555-0164. We’re here to help you make the most out of your roofing felt and ensure your roof stays strong and secure.

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