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What Do You Put Under Metal Roofs?

Posted on March 30, 2023

Estimated Reading Time : 5 Min.

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What Do You Put Under Metal Roofing

Metal roofs make a durable and long-lasting roofing option for homes and commercial buildings. However, the myth that metal roofs are noisy when it rains has put off a lot of people from choosing it as their roofing option. 

Many people that are seeking information about metal roofs come to the same question; What do you put under a metal roof? To provide answers to this question, we’ve curated a comprehensive guide on the topic. Read the guide till the end to make the best decision for your roofing system. 

What Is Roof Underlayment? 

Roof underlayment is a layer found between the roofing material and the roof deck. It’s made of different materials depending on the type of roofing system. However, for metal roofs, there are a few types of underlayment available. Some types of underlayment for metal roofs include felt, synthetic, and peel-and-stick underlayment. The main advantage of having roof underlayment is to protect the roof deck from the damaging effects of ponding water and the sun and to soundproof the roofing system. 

Without roof underlayment, a roof is more prone to damage, deterioration, rotting, and corrosion. Additionally, metal roofs, which are considered noisy during rain, storms, and hail, need to have underlayment over the roof deck. This way, the sound generated on a metal roof will be muffled, creating a soundproof environment for the people living below the roof. 

Types Of Underlayment Used For Metal Roofing

There are many types of underlayment available for different roofing systems. However, the ones mentioned below are specific to metal roofing. 

A. Synthetic Roof Underlayment

This is the newest type of underlayment on the market, as it’s manufactured using advanced technology and polymers. Synthetic underlayment is the most durable and long-lasting type of underlayment that provides a protective layer between the metal roof and the roof deck. This thick, tear-resistive layer, made of polymers, prevents water leaks and rust from forming. In fact, synthetic underlayment has a similar lifespan to a metal roof, which varies between 50 to 70 years, depending on the type of metal the roof is made of. 

B. Asphalt-Saturated Felt

Known by many different names, such as tar paper, felt, and asphalt-soaked felt, this underlayment is the most popular and common type of underlayment used for metal roofs. It’s preferred among home and business owners for its water-resistant and adhesive properties. However, the main disadvantages that it comes with are its short lifespan and its low resistance to water vapor. In some cases, this underlayment will need additional layers to provide stronger durability. 

C. Peel-And-Stick Roof Underlayment 

A peel-and-stick membrane, also known as self-adhesive underlayment, has a self-adhesive backing that allows it to be easily installed without the need for additional fasteners. It is typically made from a synthetic polymer material and has a high-tack adhesive that creates a strong bond with the roof deck. This type of underlayment is also known as a vapor barrier, preventing water infiltration and moisture from seeping into the adhesive and, thus, the roof deck. 

In regions with frequent snow or rain, metal roofs require additional protective layers to prevent water damage, such as moisture becoming trapped. Because this underlayment is self-adhesive and forms a strong bond with the roof deck, it’s the perfect choice for metal roofs in rainy and snowy regions. 

Reasons For Putting Underlayment Under Metal Roofs

For countless reasons, underlayment must be installed with metal roofs, and we’ve included some of these reasons below. Take them into account when buying underlayment for your metal roofing system. 

A. Moisture Protection

This is one of the main reasons to install underlayment between the roof deck and the metal sheets. If the metal roof is installed without underlayment beneath it, water can penetrate the roof through gaps and create leaks that cause severe damage to the building’s interior. This can lead to costly repairs and be a significant inconvenience for those living under the roof. 

B. Thermal Insulation

Though a metal roof is energy efficient on its own, having underlayment beneath it provides an additional insulative layer that cuts the cost of energy bills. With installed underlayment, a metal roof turns out to be stronger, thicker, and more protective. Underlayment is also an advantage for people seeking isolation from the warm and humid outside air. 

C. Noise Reduction

The belief that metal roofs are noisy during rain and hailstorms has led to discussions about the importance of underlayment. Regardless of the roofing material used, all types of roofing systems require the underlayment to help protect them from the elements, including rain. Metal roofs are no exception, and they are typically installed with underlayment designed to reduce the noise generated during heavy rain or hail.

To know more about roof decks, read our blog, 5 facts you didn’t know about roofing decks. 

D. Improved Aesthetics

In addition to protecting against moisture, underlayment can enhance the roof’s overall appearance by creating a smooth surface for the metal roofing to be installed. This can help prevent any irregularities in the roof deck from showing through the metal panels, resulting in a more polished and professional finish. 

With a more polished finish, the overall curb appeal of a building is improved, making it a more attractive option for potential buyers or renters.

E. Improved Fire Resistance

The fact that underlayment and metal roofs are both fire-resistant makes a home or business durable and long-lasting. In fire-prone areas, having underlayment installed can be a life savior. 

Factors To Consider When Choosing Underlayment

To build a perfect combination with your metal roof, you need to buy an underlayment that meets all the conditions your home requires, including:

A. Climate And Weather Conditions

Your local climate is a big consideration when choosing an underlayment for your metal roof. If you live in a location with frequent fires, rain, or hail, you need to buy an underlayment that suits specific weather conditions in your area. 

B. Building Codes

Your local building codes may require the use of a specific type of underlayment or have further rules that you don’t want to ignore. By using the required underlayment and following the rules of your local government, you’ll be protected from lawsuits or other issues that concern the safety of your home. Therefore, buying underlayment that matches the local building codes can enhance your home’s protection and overall appeal to potential buyers. 

C. The Type of Metal Roof

Considering the type of metal your roof is made of is essential when buying underlayment for your roofing system. As different underlayment is made for different metal roofs, installing one that matches the longevity of your roof extends its lifespan and durability. 

D. Your Budget

Some underlayment comes with advantages such as fire resistance, waterproofing, and self-adhesive properties, which are expensive. However, they make the perfect companion for your metal roof and, therefore, your home. You may want to consider expanding your budget when it comes to purchasing underlayment, as good quality material is worth it in the long run.  

Do You Want A Durable And Long-Lasting Metal Roof? 

If you are considering installing a metal roof to accompany your home for a lifetime, you are in the right place. Call BRH Enterprises today at (920) 249-4228 to discuss your metal roofing project. 

The team at our company is proficient in handling all kinds of roofing projects, including roof installation, roof replacement, and repair. With our team, you can install an underlayment that will suit your metal roof and protect your home for years to come. 

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