Roofing Underlayment: 3 Essential Types in 2023 

Roofing underlayment is a crucial component of any roofing system as it serves as a protective barrier under your roofing material. It helps safeguard your home from water, wind, and other external elements. With the right underlayment, you can extend the life of your roofing system and avoid costly damages.

There are three main types of roofing underlayment: asphalt-saturated felt, synthetic, and self-adhered. Each type has its unique benefits and is suited for different situations. By understanding the differences between these underlayment types, you can make an informed decision for your home’s roof and improve its longevity, energy efficiency, and durability.

Understanding Roofing Underlayment

History and Importance

Roofing underlayment plays a vital role in protecting your home as the first line of defense against weather elements like rain, snow, and heat. Before synthetic materials came into play, traditional roofing underlayment was made of asphalt-saturated felt, which has been the popular choice for many years due to its affordability and effectiveness.

In recent times, advances in technology have introduced new roofing underlayment materials, focusing on improved durability and resistance to water and fire damage. As a homeowner, understanding the different types of roofing underlayment and their benefits will help you make an informed decision when choosing the right one for your home.

Materials Used

There are three main types of roofing underlayment materials available: asphalt-felt underlayment, non-bitumen synthetic underlayment, and asphalt-saturated felt underlayment.

1. Asphalt-felt underlayment: This has been the go-to choice for many homeowners due to its affordability. It is made of fabric-like material such as polyester, wood cellulose, fiberglass substrate, and soaked in asphalt to make it stronger and water-resistant. It is available in two weights: 15 pounds and 30 pounds per 100 square feet. However, it may not be the most durable option and can tear easily during installation.
   
2. Non-bitumen synthetic underlayment: This type of underlayment is made from synthetic materials like rubber polymers, synthetic fibers, and synthetic polymers. It provides enhanced durability and resistance to water and fire damage. Some synthetic underlayments contain a fiberglass reinforcement layer for added strength. Non-bitumen synthetic underlayment can be more expensive than asphalt-felt but offers better performance in terms of longevity and protection.
   
3. Asphalt-saturated felt underlayment: This is another type of underlayment made from traditional asphalt-saturated felt, but with added waterproof materials and polymer film. It shares some similarities with asphalt-felt underlayment, but with improved water resistance.
   

Choosing the right roofing underlayment for your home depends on factors like your budget, your local building codes and regulations, and the preferences of your roofing contractor. By considering the advantages and benefits of each type, you’ll be well-equipped to make the best decision for your home’s protection.

Roofing Underlayment Types

When it comes to protecting your home, it’s crucial to choose the right type of roofing underlayment. This article will discuss three main types of underlayment used in residential roofing systems: Asphalt-saturated Felt, Non-bitumen Synthetic, and Rubberized Asphalt. Understanding their characteristics will help you make an informed decision on the best roof underlayment for your needs.

Asphalt-saturated Felt

Asphalt-saturated felt, often referred to simply as “roofing felt” or “tar paper,” is a type of building material commonly used in roofing and construction. It is made from a base material, usually a heavy-duty paper or fiberglass mat, which is saturated with asphalt to make it waterproof and resistant to moisture. Here are some key points about asphalt-saturated felt:

• Waterproofing: The primary purpose of asphalt-saturated felt is to provide a waterproof barrier between the roofing material (such as shingles) and the underlying structure of a building. It prevents water from seeping into the roof deck and causing damage to the interior of the structure.
• Weather Resistance: Asphalt-saturated felt also provides protection against wind, rain, and other weather elements. It helps to create a weather-resistant layer that shields the roof from the effects of the environment.
• Underlayment: Roofing felt is typically installed as an underlayment beneath other roofing materials, such as asphalt shingles, wood shakes, or metal roofing. It serves as a protective layer between the roofing material and the roof deck.
• Durability: Roofing felt is designed to be durable and long-lasting. It can withstand exposure to UV rays from the sun without deteriorating too quickly. However, its lifespan can vary depending on the quality of the material used and the local climate conditions.
• Moisture Management: In addition to its waterproofing properties, asphalt-saturated felt also helps manage moisture within the roofing system. It allows any trapped moisture to escape without damaging the roof structure.
• Installation: Roofing felt is typically rolled out in overlapping layers and secured to the roof deck using nails or staples. Proper installation is essential to ensure that it functions effectively as a moisture barrier.
• Types: There are different grades and types of roofing felt available, with varying thicknesses and weights. Heavier and thicker grades are typically used in areas with harsher weather conditions or as an extra layer of protection in critical areas of the roof.
• Code Requirements: Building codes and regulations may dictate the type and installation of roofing felt in specific regions. It’s essential to consult local building codes and follow manufacturer recommendations when installing roofing felt.

Non-bitumen Synthetic Underlayment

Non-bitumen synthetic underlayment is an alternative roofing underlayment material that is used to provide a protective barrier between the roof deck and the roofing material (such as shingles or tiles). Unlike traditional asphalt-saturated felt, non-bitumen synthetic underlayment is made from various synthetic materials, such as polyethylene, polypropylene, or fiberglass. Here are some key characteristics and advantages of non-bitumen synthetic underlayment:

• Waterproofing: Non-bitumen synthetic underlayment is designed to be highly waterproof, preventing water from infiltrating the roof structure. It offers superior waterproofing compared to traditional felt underlayment.
• Lightweight: Synthetic underlayment is typically lighter than asphalt-saturated felt. This lightweight nature makes it easier to handle during installation and reduces the overall weight load on the roof structure.
• Strength and Durability: Non-bitumen synthetic underlayment is known for its strength and durability. It is less prone to tearing and damage during installation and in high-wind conditions, providing a longer-lasting roofing solution.
• UV Resistance: Many synthetic underlayment are designed to be highly resistant to UV radiation, preventing degradation and damage from prolonged exposure to sunlight. This is a significant advantage over traditional felt, which can break down over time when exposed to UV rays.
• Slip Resistance: Synthetic underlayment often has a textured surface that provides good traction for roofing contractors working on the roof. This slip resistance can improve safety during installation.
• Installation Efficiency: The lightweight and flexible nature of synthetic underlayment makes it easier and quicker to install than traditional felt. It typically comes in rolls that can be quickly rolled out and fastened to the roof deck.
• Tear Resistance: Synthetic underlayment is less likely to tear or wrinkle during installation, ensuring a smooth and uniform surface for the roofing material to be applied over it.
• Resistance to Mold and Rot: Unlike organic materials like felt, synthetic underlayment is not susceptible to mold, mildew, or rot, even in damp conditions.
• Versatility: Synthetic underlayment can be used in various roofing applications, including steep-slope roofs, low-slope roofs, and metal roofing installations.
• Code Compliance: Synthetic underlayment materials typically meet or exceed building code requirements for roofing underlayment.

Non-bitumen synthetic underlayment is often considered the best roofing underlayment for long-lasting protection and enhanced energy efficiency. It works well with a variety of roof types, including asphalt shingles.

Rubberized Asphalt Underlayment

Rubberized asphalt underlayment is composed primarily of asphalt and rubber polymers. Its unique composition offers increased durability, flexibility, and waterproofing capabilities, making it an excellent choice for areas prone to extreme weather conditions. It is designed to provide superior protection against moisture and to enhance the overall performance of roofing systems. It is often used as an alternative to traditional asphalt-saturated felt or non-bitumen synthetic underlayment. Here are some key characteristics and advantages of rubberized asphalt underlayment:

• Waterproofing: Rubberized asphalt underlayment is exceptionally effective at preventing water infiltration. It is engineered to be highly waterproof and can create a watertight seal when properly installed.
• Durability: This type of underlayment is known for its durability and resistance to damage. It can withstand various weather conditions, including extreme heat, cold, and UV exposure, without breaking down or deteriorating.
• Self-Healing Properties: Rubberized asphalt underlayment often has self-sealing properties. If it is punctured or damaged during installation, it can typically “heal” or self-seal around the puncture, maintaining its waterproof integrity.
• Tear Resistance: Rubberized asphalt underlayment is tear-resistant, which means it can withstand the stresses and movements that can occur on a roof, especially in high-wind areas.
• Flexibility: It is designed to be flexible, allowing it to conform to the contours of the roof deck and adapt to temperature-related expansion and contraction.
• Improved Traction: The surface of rubberized asphalt underlayment is often textured or coated to provide improved traction for roofing contractors working on the roof, enhancing safety during installation.
• Reduced Noise: Rubberized underlayment can help reduce noise transmission, making it a suitable choice for homes or buildings where noise reduction is a concern.
• Compatibility: It is compatible with a wide range of roofing materials, including asphalt shingles, metal roofing, and tile roofing systems.
• Ice and Water Shield: Some rubberized asphalt underlayments are marketed as ice and water shield underlayments, which provide additional protection against ice dams and water intrusion in vulnerable areas of the roof, such as eaves and valleys.
• Code Compliance: Rubberized asphalt underlayment typically meets or exceeds building code requirements for roofing underlayment, offering peace of mind to homeowners and builders regarding its performance and safety.

Although this type of underlayment is typically more expensive than the other options, its high-performance characteristics make it a worthwhile investment for homeowners seeking premium protection.

By understanding these three types of roofing underlayment, you can confidently make the best choice for your specific needs to ensure long-lasting protection for your home.

Benefits of Roofing Underlayment

Protection from Weather

Roofing underlayment provides a crucial protective layer that helps safeguard your home from various weather-related elements. It greatly reduces the risk of water damage by offering excellent water resistance, which is essential especially in areas prone to heavy rain or snowfall. With a high-quality underlayment, you can minimize the chances of leaks, ice dams, and wind-driven rain penetrating your roof.

In addition to protecting against moisture, underlayment can also shield your home from extreme temperatures and harsh weather conditions. This layer helps keep high temperatures at bay during hot summer months, providing better protection against heat damage. In cold climates, it contributes to retaining the heat inside your home, reducing heating costs and improving overall comfort.

Roofing underlayment is designed to withstand strong winds and high winds, helping to maintain your roof’s structural integrity and durability. This added stability ensures that your roof can handle adverse weather conditions without succumbing to damage.

Additional Benefits

Beyond weather protection, roofing underlayment serves a number of other important functions:

• It creates a waterproof seal, effectively forming a waterproof barrier between your roofing materials and your home’s structure. This helps prevent fungal growth, decay, and other moisture-related issues.
• Underlayment offers additional insulation, contributing to your home’s energy efficiency by reducing heat loss or gain, depending on the season.
• This extra layer provides enhanced protection to your roof surface, minimizing the risk of damage during the installation process or when exposed to fluctuating temperatures and harsh environments.
• An effective underlayment can also help evenly distribute the weight of your roofing materials, adding to the overall strength and resilience of your roof structure.

In summary, investing in a suitable roofing underlayment means providing optimal protection and strength for your home, ensuring it can better withstand various challenges posed by weather and external factors.

Choosing the Right Underlayment

Considerations for Different Roof Types

When selecting the right type of underlayment for your roof, it’s essential to consider the top roof layer material. For metal roofs, rubberized or synthetic underlayment can provide added protection against water, whereas asphalt-felt may be the best choice for tile roofs. For flat roofs or low-slope roofs, it is vital to opt for a material that prevents water from pooling, while for steep slope roofs, durability and added support are essential features.

Local Building Codes

Always refer to your local building codes before choosing a roof underlayment. These codes dictate specific requirements for materials and installation, ensuring your roof system adheres to regional safety and performance regulations. Consulting the codes will help you make the best choice for your home, while also avoiding potential fines or penalties.

Global Climate Adaptations

The climate in your area plays a crucial role in determining the most suitable underlayment for your roof. In colder climates or areas with extreme temperatures, it’s crucial to choose an underlayment that can withstand harsh conditions and provide efficient insulation. Synthetic underlayment is often the preferred choice for its durability and resistance to water and fire damage. Conversely, in less extreme climates, felt or rubberized underlayment could offer the additional protection you need for your roof system.

Conclusion

In summary, it is crucial to choose the right type of roofing underlayment for your home. This choice depends on factors such as your local climate, roofing material, water resistance, and cost. The three main types of underlayment are felt, self-adhered, and synthetic.

Felt underlayment is the most affordable option and is widely used due to its availability and ease of installation. It provides a basic layer of protection against water and weather conditions. However, it is less durable than the other options and may not be suitable for long-term, heavy-duty use.

Self-adhered underlayment is a more advanced choice that offers superior water resistance and durability compared to felt. This type of underlayment features adhesive qualities, ensuring that the material remains securely in place and can handle severe weather conditions. A disadvantage may be the higher cost associated with this option.

Lastly, synthetic underlayment provides the highest level of protection and durability among the three types. It is typically made from materials such as fiberglass and asphalt, which give it exceptional tear resistance and stability. Roofing professionals may prefer this option due to its superior water resistance and long-lasting performance. However, the increased cost and potential for UV damage should be taken into consideration.

By carefully weighing the pros and cons of each type of underlayment, you can make an informed decision that best fits your home’s needs and budget. A well-chosen underlayment will help protect your roof, prolong its lifespan, and ultimately keep your home comfortable and dry.