Thermal Movement in Metal Roof Systems

Did you know thermal movement can affect your roof’s performance and lifespan? As a homeowner, you may have invested in a metal roof system due to its durability and longevity.

It’s essential to know that they are highly susceptible to thermal expansion and contraction, which can cause stress on the roof system and result in leaks and damage if left unaddressed.

Let’s explore this concept, why it occurs, and how business owners and homeowners can mitigate its effects.

How does it happen?

Thermal movement in metal roofs results from the material’s expansion and contraction due to temperature changes. Metal expands when they are heated and contracts when cooled, and this can cause stress on the roof system if not accounted for during installation and maintenance.

Let’s consider an example of a 100-foot-long metal roof that experiences a temperature change of 50°F. According to the Coefficient of Thermal Expansion (CTE) for steel, 6.5 x 10^-6 in/in/°F, the roof will expand by approximately 0.325 inches.

This may not seem like much, but the expansion can add significant stress to the roof system when multiplied over the entire roof length.

What causes this?

Here are some causes of thermal expansion in metal roof systems:

Cooling breezes: They can cool down the metal roof surface, causing it to contract. This contraction can put stress on the roof system, especially if it is not installed properly or has an insufficient allowance for thermal expansion and contraction.

Cloud cover: When a cloud passes overhead, it can block the sun’s rays and cause the roof surface to cool down, leading to contraction. Similarly, when the sun re-emerges from behind the cloud, the roof surface can heat up and expand, causing stress on the roof system.

Rain: It can cause the metal roof surface to cool down rapidly, leading to contraction and stress on the roof system. And if the roof is not properly installed or maintained, rainwater can accumulate and add weight to the roof, further exacerbating the effects of thermal movement.

Other environmental factors, such as wind and humidity, can also impact thermal movement in metal roofs. Wind can lead to rapid changes in temperature by carrying cool or warm air over the roof surface, while high humidity can lead to condensation on the roof, which can affect thermal expansion and contraction.

How to Control Thermal Movements

The best thing is to allow room for expansion and contraction during installation and maintenance. This can be achieved through methods, such as using fasteners that allow movement, installing expansion joints, and providing adequate ventilation.

Suppose a metal roof is installed too tightly or without sufficient thermal expansion and contraction allowance. In that case, the resulting stress can cause fasteners to break or loosen and the roof panels to warp or buckle. This can result in gaps that allow water to penetrate the roof, leading to leaks and other issues.

Proper ventilation is also crucial for controlling thermal movements in metal roofs. Adequate ventilation can help regulate the temperature and humidity levels in the attic space, which can help prevent condensation and other issues that can affect the roof’s thermal movement.

We can help

At HKC Roofing, we understand the essence of properly controlling thermal movements in metal roofs to ensure their longevity and durability. That’s why we use state-of-the-art techniques and materials to ensure your metal roof system is properly installed and maintained to withstand the effects.

We can help you select the right materials and design for your metal roof system and ensure it allows expansion and contraction. Whether you need a new roof installed, regular maintenance to keep your roof in top condition, or repairs due to the effects of thermal movement, we can help. Schedule an estimate today and protect your investment for years to come.

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