Roofing Underlayment: Types, Installation, and Benefits

A roofing system is a complex structure that involves multiple layers and components, each serving a specific purpose. 

One of the essential components of a roofing system is the underlayment, a protective layer installed between the roof deck and the roofing material. 

The underlayment provides an extra layer of protection against water infiltration, prevents leaks, and improves the roof’s overall durability. 

So here we’ll discuss the different types of roofing underlayments, their installation methods, and the benefits of installing them.  

Types of Roofing Underlayment

Roofing underlayment comes in different materials and types, each with its advantages and disadvantages. The most common type of roofing underlayment are

Asphalt-saturated felt: Also known as tar paper, this type of underlayment is made from organic materials such as wood pulp or rag fibers. It is the most affordable option but has a shorter lifespan compared to the synthetic underlayment.

Synthetic underlayment: Made from materials such as polypropylene, this type of underlayment is more durable and resistant to tearing and UV radiation. It is more expensive than asphalt-saturated felt but has a longer lifespan and better performance.

Rubberized underlayment: This type of underlayment is made from rubber and is highly resistant to moisture, making it an ideal choice for areas with high humidity or heavy rainfall.

Self-adhering underlayment: Also known as peel-and-stick underlayment, this type of underlayment is easy to install and does not require any additional adhesive. It is ideal for steep-slope roofing and areas prone to wind damage.

Factors to Consider when Choosing Underlayment

Choosing the right type of underlayment for your roofing system depends on several factors, such as the climate, slope, and roofing material. 

For example, in areas with high humidity or heavy rainfall, a rubberized underlayment would be a better choice to prevent water infiltration. In areas prone to wind damage, a self-adhering underlayment would be ideal to prevent wind uplift. 

The slope of the roof also plays a significant role in determining the type of underlayment to use. Steep-slope roofs require a more robust underlayment to prevent water infiltration and provide better traction for workers during installation.

Installation Methods

There are two main methods for installing roofing underlayment: the shingle method and the peel-and-stick method.

Shingle method: This method involves installing the underlayment in between the roof deck and the shingles. It is the most common method and is ideal for sloped roofs. It involves nailing the underlayment to the roof deck and overlapping each row by at least six inches to prevent water infiltration.

Peel-and-stick method: This method involves installing the underlayment directly onto the roof deck using an adhesive backing. It is ideal for steep-slope roofs and does not require any nails or an additional adhesive. The underlayment is overlapped by at least six inches to prevent water infiltration.

Benefits of Underlayment

Installing roofing underlayment provides several benefits, including:

• Prevents water infiltration: Underlayment provides an extra layer of protection against water infiltration, preventing leaks and water damage to the roof deck and the interior of the house.
• Improves roof durability: Underlayment improves the roof’s overall durability and lifespan by providing an additional layer of protection against weathering and other external factors.
• Provides better traction: Underlayment provides better traction for workers during installation, improving safety and reducing the risk of accidents.
• Enhances energy efficiency: Certain types of underlayment, such as reflective underlayment, can enhance the roof’s energy efficiency by reflecting heat and reducing the amount of heat absorbed by the roof.
• Meets building codes: Installing underlayment is often required by building codes to ensure the roof’s safety and longevity.

Maintenance and Repair

Maintaining and repairing your roofing underlayment is essential for ensuring the roof’s longevity and preventing water infiltration. Regular inspections can help identify any damage, such as tears or punctures, and take prompt action to repair them. It is also important to ensure that the underlayment is properly sealed around any roof penetrations, such as chimneys or vents, to prevent water infiltration.

How do I know if I need to use a specific type of roofing underlayment?

The type of roofing underlayment you need will depend on several factors. For example, if you live in an area with heavy rainfall or snow, you may need a more water-resistant underlayment. 

If you have a low-slope or flat roof, you may need a specific type of underlayment designed for this type of roof. The type of shingles you are using may also impact the type of underlayment you need. 

It’s best to consult with a roofing professional who can assess your specific situation and recommend the best type of underlayment.

Can I install the roofing underlayment myself, or do I need to hire a professional?

While it’s possible to install roofing underlayment yourself, it’s recommended that you hire a professional roofer to ensure that it’s installed correctly. 

Improper installation can lead to leaks and other issues, so it’s best to leave it to the experts. 

A professional roofer will also have the necessary tools and experience to complete the job efficiently and safely.

What is the difference between the synthetic underlayment and asphalt-saturated felt?

Asphalt-saturated felt is a traditional type of underlayment that has been used for many years. It is made from paper or fiberglass that is saturated with asphalt, which makes it water-resistant. 

Synthetic underlayment, on the other hand, is typically made from polypropylene or polyester and has a higher level of durability and moisture resistance. It is also typically lighter and easier to install than asphalt-saturated felt. 

Synthetic underlayment is becoming increasingly popular among roofing professionals due to its superior performance.

How long does roofing underlayment typically last?

The lifespan of roofing underlayment will depend on several factors. For example, the type of underlayment, local climate conditions, and how well it was installed will all impact its lifespan. 

In general, most roofing underlayments will last between 15 and 30 years. However, it’s important to have your roof inspected regularly to identify any potential issues with the underlayment and to ensure that it’s replaced when necessary.

Conclusion

Roofing underlayment is a crucial component of a roofing system that provides an extra layer of protection against water infiltration and improves the roof’s overall durability. 

Choosing the right type of underlayment and installing it correctly can enhance the roof’s safety, longevity, and energy efficiency. Regular maintenance and repair can help prevent water infiltration and prolong the underlayment’s lifespan.