Roofing Underlayment Types: What You Need to Know


Now that we’ve discussed the different types of roofs, it’s time to discuss a vitally important part of the roof: the roofing underlayment, and the different roofing underlayment types.

Roof underlayments go underneath the actual roof and insulation, but above the roof deck, and they’re essential for protecting your home from weather and the elements, particularly rain and hail. All roof underlayments have a basemat, which is the flexible base layer.

This underlayment is so vital because in addition to the purposes already listed, it is also your last line of defense in the event that the outer roof layer is damaged. In the unfortunate case where the roofing material gets broken, torn off, or crushed, this layer needs to be able to protect the house.

The tiles or topmost roofing material are functional and aesthetic, but the underlayment is the primary waterproofing element.

Roofing Underlayment Types

There are three common types of roofing underlayment:

  • Common Asphalt-saturated felt, or “felt paper,” 15#, 30#, 40# etc. has an organic basemat (basically cardboard) that is saturated with asphalt, giving it good waterproof quality.  Asphalt-saturated felt is stiff and sturdy, which means it holds up reasonably well to impact from things like hail and airborne debris. Asphalt-saturated felt is a cost-affordable option still in use today,, but not the most durable, and used to be the most popular roofing underlayment type until better materials overtook it.
  • Rubberized asphalt underlayment, predictably, consists of a fiberglass basemat saturated with rubberized asphalt..  The fiberglass mat will not absorb moisture and  rubberized underlayment is very elastic, which makes it a great choice for areas that have extremely hot or cold weather. SBS rubberized underlayment is the most popular underlayment in use in our area and a great step up from common felt paper.
  • Synthetic underlayment, or non-bitumen synthetic underlayment, is gaining in popularity. It’s made with durable plastics such as polyethylene or polypropylene, which makes it a strong, elastic, and water-resistant choice. Synthetics are still relatively new and it’s use as the best underlayment under tile roofs has still not been proven.

What Is the Best Roofing Underlayment for an Arizona Roof?

The best roofing underlayment for homes in Arizona is the one that accounts for the extraordinary heat stress of Arizona’s summers and the water and wind stress of the monsoon season. It also depends upon the roofing material chosen. Clay tile roofs may perform better with a different choice than the concrete tile roofs that are so popular and attractive right now.

A good roofing company will assist you in determining the best roofing and underlayment for your new roof or for your roof repair. If you work with a qualified and experienced company like Roofstar, you will be given several options to complete your project since there are different ways to meet the same goals and we have the expertise to guide you in these important decisions.

Since there are constant changes in materials for these roofs, we recommend you contact a trusted roofing company like ours to find the most advanced option that will give you the best product at the best value.

Get the Truth About Your Roof

Here at Roofstar we pride ourselves on offering you the absolute truth about your roof and discussing whether repairs or replacement is ideal  for your particular situation. Give us a call right away at (480) 426-1915 to get the best roofing underlayment and best roof possible.

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We can handle all kinds of residential roof repairs. Call us today to schedule an assessment with one of our Field Inspectors. We also assist with insurance claims. Learn more about Our Real Estate Services.

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