Heat, Humidity, and Your Roof

Jun 25, 2024

The dog days of summer are here. While Wisconsinites might love being outside during June, July, and August, our roofs react differently.

“When we talk about roof damage, it’s easy to think about heavy rain, wind, or snow,” said Wendy Cline, co-owner of J & B Construction. “But heat is also a common pain point for our roofs. For example, if it’s 90 degrees out, your unshaded roof can reach 150 degrees, causing wear and tear.”

High heat and humidity, especially during July and August, can cause these problems to develop on your roof:

Damaged Shingles

“When asphalt shingles on your roof are new, they are flexible and can adjust to the shape of your roof,” Wendy said. “However, extreme heat can dry them out over time.”

Dry shingles can crack, protrude from the rest of the roof, or become misshapen. This can cause leaks and gaps, making your house more vulnerable to the outside elements.

In addition, when the shape of the shingles is abnormal, nails and screws can pop out, causing you to lose the shingles altogether.

Thermal Shock

Wisconsin weather can be unpredictable, with severe temperature differences from one day to the next. In the summer specifically, days can be hot, and nights can be cool.

“This swing in temperature can cause thermal shock to your roof,” said Wendy. “Heat makes your roofing material expand while cooling contracts it. The constant change causes stress to your roof and can lead to the materials splitting or cracking.”


Just like the color of your skin can become a bit darker when you spend time in the sun, your roof’s color can become bleached when exposed to heat. Ultimately, this can impact your house’s curb appeal.

“The color of the roof also correlates to protecting your home,” Wendy said. “The color helps reflect the sun’s light, keeping direct heat from entering inside.”

Furthermore, heat can also cause the metal components of your roof to rust, weakening it little by little.

Appearance of Rust, Mold, and Mildew

Rain and thunderstorms also make an appearance during Wisconsin summers. When it rains, the gutters lining your roof remove the water and direct it elsewhere. If your gutters are clogged or not working properly, long-standing water on your roof can cause rot.

“Mold and mildew, which can be common on roofs, often grow in damp, shady conditions, like in the corners or near the awnings of your roof,” said Wendy.

J & B Construction Can Help

“Small problems with your roof can lead to massive headaches down the line,” Wendy said. “That’s why it’s so critical to replace or repair your roof if you see any of the above issues. J & B Construction can recommend the right solution for your roof and has an in-house metal shop to help with repairs.”

J & B Construction can also help you prevent problems from developing on your roof. Its expert attic insulation can provide a barrier between your roof and the outside temperatures, while its custom-made built-in and seamless gutters protect your roof from water damage.

For all things roofing, J & B Construction, southeastern Wisconsin’s most trusted roofing company, has you covered. If you require roofing repairs, contact us today.

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Enjoy Peace Of Mind
 The only complaint I have is when I have J&B do my roof in another 30 years or so, is Dave their sales man (a great guy) would not guaranty I could get the same great crew I had this time. They did a fantastic job. Much better than the last roofing company did. A nice bunch of guys. Did a very nice job cleaning up. I'd give them 10 stars but 5 is the limit. If you need a roof done this is the company you want to do it. One more point I need to make. The guys that did the chimney flashing are artists. I went up on the roof when they were done and was very pleased with not only the roofing job but the sculptured sheet metal work. It's kind of a shame it's on the roof and not hanging on the family room wall :). You get the point. Hire em. You'll like em. 
 We live in a historic designated neighborhood and recently had our 30 year wood shingle roof replaced with another wood roof and new gutters. From Day 1 of the project to the final day, the entire team was responsive, professional, and very competent. When some minor changes were proposed by us they quickly and effortlessly complied. After going through this experience with J&B, I would highly recommend them to anyone considering a roof and gutter replacement, whether it be a simple or complicated project. 
 J & B did an amazing job from start to finish. The initial meeting at my home took place exactly at the time that was agreed upon and Scott was thorough in his explanations and transparent about costs. When the time came to begin the project, the team that showed up was friendly, professional and timely in getting the project done. The cleanup afterward was such that it looked like they hadn't been there at all. The roof looks great, there were no surprises and Scott came by to inspect the work and explain the warranty upon job completion. I would highly recommend them. 
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W140 N10589 Fond du Lac Ave, Unit C
Germantown, WI 53022
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