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Posted by McElroy Metal ● Aug 1, 2019 7:00 AM

What is the Best Underlayment for a Metal Roof?

Underlayments are designed to provide a secondary barrier of weather protection for a building's interior. During construction, an underlayment helps keep the interior of the structure dry. They also provide contractors a surface to walk on. Once the roof construction is finished, if for some reason the metal roofing above is compromised, an underlayment also helps to shed water away from the conditioned building interior. In essence, underlayments protect the structure and anything stored directly below the roof both during and after construction.

what is the best underlayment for a metal roofHistorically, asphalt-saturated felt underlayments, sometimes called roofing tar paper, were the go-to roof underlayment choice. However, this style of underlayment presents a few challenges.

Asphalt-saturated felt underlayment is typically available in 2 or 4 square rolls which requires numerous rolls to complete an averaged sized roof.  Additionally, installing this style of underlayment can be a challenge as it has a tendency to buckle and wrinkle. Perhaps most important is the fact that as a paper product, asphalt-saturated felt underlayment can degrade rather quickly.

To offset this disadvantages, we recommend selecting a synthetic underlayment for metal roofing projects instead of the asphalt family of products.  

Manufactured from high-performance polymers, synthetic underlayments address the downside of asphalt-saturated felt underlayment in the following ways.

Hydrashell metal roof underlaymentSynthetic underlayment is typically manufactured in 10 square rolls, so fewer rolls are needed to cover a roof completely. Significantly lighter than asphalt-saturated felt underlayment, synthetic underlayment is also easier to work with and maneuver. The nature of the product also means that it is easier and quicker to install with fewer buckles and wrinkling.

Finally, once again due to its polymer composition and strength, synthetic underlayment offers greater longevity than its paper-based counterpart. So, if you are looking for the best underlayment to install under a metal roof, a synthetic underlayment is your best option.

Learn More

Want to learn more about metal roof underlayment and how to install it? Check out this article.

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About McElroy Metal

Since 1963, McElroy Metal has served the construction industry with quality products and excellent customer service. The family-owned components manufacturer is headquartered in Bossier City, La., and has 13 manufacturing facilities across the United States. Quality, service and performance have been the cornerstone of McElroy Metal’s business philosophy and have contributed to the success of the company through the years. As a preferred service provider, these values will continue to be at the forefront of McElroy Metal’s model along with a strong focus on the customer.

Topics: Metal Roofing, Substructural Components, FAQ, Installation, Architect Resources

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