3 Types of Roofing Underlayment and Its Great Importance

Roofs, as we all know, are an essential component of any home. A home’s roof is what protects it from storms, cold, and heat. It keeps us warm and dry no matter what the weather is like outside. However, most roofing types have numerous seams, which is why roof underlayment is so beneficial.

Whether or not your roof type requires it, a roofing underlayment is usually a good option because it adds another layer of protection to your home. If you’ve ever wondered, “What is roof underlayment?” or “How should I choose a roofing underlayment?”, you’ve arrived to the correct place.


Roofing Underlayment

What is roofing underlayment?

Roofing underlayment is applied to the surface of your roof deck before the roofing is installed. The underlayment will not be visible until your roof construction is complete. It will appear as sheets of asphalt-saturated felt, rubberized asphalt, or non-bitumen synthetic underlayment before being concealed by the roofing materials.

The roof deck, often known as roof sheathing, could be:

  • Plywood
  • OSB, or
  • Step sheathing

These boards are attached to the rafters or trusses to assist stabilize them and provide structure to the entire roof.

Roofing underlayment comes in a variety of styles. Each type has different levels of durability and quality. It’s comprised of water-resistant or waterproof materials to keep your roof deck safe from water penetration, heat, snow, and other inclement weather.

“What roofing underlayment should I use?” you might inquire. Then think about your priorities in terms of water resistance, cost, and environmental friendliness. Rubberized asphalt is perfect if you need something waterproof. If you’re on a tight budget, asphalt-saturated felt is the way to go.

Types of roofing underlayment

In general, there are three types of roofing underlayment: felt, self-adhered, and synthetic. Each has its own set of advantages and disadvantages, and which one you choose is mostly determined by your roofing contractor’s comfort level as well as local construction standards and regulations.

  1. Felt Underlayment

One of the most traditional types of roofing underlayment. Tar paper or felt paper are two frequent names for it. It’s made of a water-resistant organic mat or paper that has been wet with asphalt.

Felt underlayment is generally available as two standard weights:

  • 15 pounds per hundred square feet or No. 15 felt
  • 30 pounds per hundred square feet or No. 30 felt

No. 15 felt can be used for light-weight crafts. It does, however, rip readily and can absorb water and wrinkle if exposed to the outdoors during installation.

Contractors may propose No. 30 felt, which is more durable than No. 15 felt, to homeowners who choose felt underlayment. It can be placed in many layers for added protection, just like any other underlayment product.

When dealing with slate or tile shingles, some roofing professionals prefer to utilize felt underlayment, while others prefer self-adhered underlayment. It may differ depending on the country’s geography.

  1. Self-Adhered Underlayment

This type of roofing underlayment comprises a high percentage of asphalt and rubber polymers, making it a water-resistant option.

The sticky back of self-adhered underlayments allows them to attach to the roof deck. This sticky backing aids in the waterproofing of the roof deck and underlayment. This sort of underlayment is designed to protect the roof from damage in areas where water collects or where the roof deck has been penetrated.

Some examples of leak-prone areas include:

  1. Eaves
  2. Valleys
  3. Vents
  4. Chimneys, and
  5. Skylights

In areas with harsh winter weather, self-adhered underlayments are extremely valuable.

To enhance weather resistance, the upper surface of this type of roofing underlayment may comprise granulated, polyethylene, or polyester components. It also produces a non-skid surface, which is intended to make roofers’ jobs safer by making it simpler for them to move around on.

  1. Synthetic Underlayment

Synthetic underlayment has become a popular option for homeowners in the last decade or so. While the materials used vary by manufacturer, most synthetic roofing underlayment is made up of numerous layers of woven polymers.

Several advantages of synthetic underlayments include:

  • Tear-resistant and durable
  • It covers more area per roll and typically lighter (in comparison to most other types of underlayment products), reducing ladder trips
  • Secure walking surface
  • Lines are well defined and overlap guides for easier installation
  • It repels water and is mold-resistant.

Why is roofing underlayment necessary?

Your shingles are undoubtedly your first line of defense in the never-ending struggle against the elements that homeowners and contractors wage. Shingles can help reflect sunlight, block precipitation, and endure strong winds.

However, roofing underlayment adds a second layer of protection that:

  • Protects your roof against shingles tearing away due to severe winds.
  • Helps to prevent your roof deck from ice dam damage during cold weather.
  • Protects your roof from harsh weather during the installation procedure, prior to shingle attachment

Your home’s roofing system must comprise a roofing underlayment product and a roof covering to meet local construction requirements. Underlayment is also required by shingle manufacturers as part of their guarantee.

How to Pick the Right Roofing Underlayment for Your Roof

The most crucial aspect of deciding on a roofing system is to consider your budget. Finding the correct underlayment for your home means figuring out what works best with your roof type.

Metal roofs, for example, benefit from a synthetic underlayment with a stronger heat resistance (due to the metal’s ability to trap more heat), but a standard asphalt shingle roof will benefit from a roofing felt underlayment.

It’s also crucial to think about the environment in which you reside and the regular climate.

If you live in a hotter area, you’ll want to choose an underlayment that can withstand the heat, whereas if you live in a snowy region, you’ll need something more durable.

Finally, when it comes to choosing your underlayment, you should think about cost. Various types of roofing underlayment are suitable for various budgets.

Determine your budget, and you’ll be able to determine what underlayment options are available to you more simply.

Seek advice from the experts

Roofing underlayment can help extend the life of your roof and keep your home dry and safe.

Always remember that it is always easier to prevent water intrusion than to deal with costly repairs or damage.


Roofing Underlayment


EcoShield Roofing specializes in roof replacements and repair for metal and shingle roofs. We are a roofing business with all the correct credentials and the required local and state licenses to get your job done right. 

We also offer roof repair and gutter installation to ensure that your roof continues to work properly for years to come. To get started on your new roof, schedule a free estimate now!

Avatar photo

Author: William Sessions

William Sessions started a roofing business in 2018 with a mission to create high-quality roofs for Winston-Salem and surrounding areas. He did jobs for Safeco, Liberty Mutual, All-State, and Nationwide for two years. In that experience, he learned how to properly inspect for Hail, Wind and other damages to shingles that would impact insurance claims. After that, he started his own family business and proudly served roofing service in North Carolina. He leverages his roofing knowledge and provides useful insights through blogs on ecoshieldnc.com