The Importance of Underlayment

March 17, 2018 posted In Roofing

We all know that the weather in Chicago is extremely unpredictable. With high winds, rain, and snow present throughout the year, Chicago roofs can take a serious beating from the elements. That’s why it is imperative that your new roof is properly constructed from beginning to end, starting with the roof’s underlayment.

The underlayment is the part of the roof that provides an extra layer of protection between the roof deck and the shingles. For the most part, homeowners don’t understand the intricacies involved in a proper roofing installation system, and that includes the fact that roofing shingles alone do not provide the best protection. Roofing shingles are actually not waterproof on their own, so they need a leak protection system in place underneath them to fully protect your home.

Roof underlayment is a critical sub-roof system that provides a secondary layer of defense underneath the roofing shingles. It is the best way to protect your home from moderate to substantial precipitation throughout the year, and that includes the wind-driven rain and ice/snow build-up that creates dreaded ice dams. Ice dams occur when snow builds up on the roof and temperature changes cause it to melt in certain areas but not others, trapping moisture in the roof and causing detrimental leaks.

Types of Roof Underlayment

There are three main types of underlayment for roofs:

  • Asphalt-saturated felt – water-resistant, but not waterproof; available in two thicknesses, 15- and 30- pound
  • Rubberized asphalt – self-sealing and self-adhering, moisture-resistant, can be used in high-temperature situations
  • Non-bitumen synthetic – lightweight and high-strength, wrinkle-free and resistant to fungal growth, and completely resistant to moisture

new roof underlayment

The photo above shows an example of felt roofing underlayment before it is rolled out onto the roof.


Roof Underlayment Benefits

Roofing underlayment has many benefits and should definitely be used when installing a new roof in Chicago. The many benefits of underlayment are as follows:

  • Allows moisture to escape from your attic and provides a layer of protection against wind-driven rain
  • Helps resist “telegraphing”, or wrinkling and buckling, allowing for a better-looking roof
  • Helps prevent inside moisture from becoming trapped within your roofing system- and possibly causing mold, mildew, and expensive structural damage
  • Provides long-lasting leak protection


To learn more about roofing underlayment and how Archway provides this service as part of all of our roofing replacement systems, please contact us today to set up a complimentary consultation.

chicago roof underlayment