As summer temperatures soar, the temperatures on your roof soar even higher. Roof temperatures are typically 8˚C to 40˚C higher than temperatures on the ground.
Consider these numbers on a 32˚C day:
White Asphalt Shingles 40 – 60˚C
Gravel Roofing 52 – 60˚C
Unpainted Metal Roofing 59 – 63˚C
Black Asphalt Shingles 60 - 75˚C
Asphalt shingles are manufactured at much higher temperatures than even the hottest summer days, and therefore, can withstand high temperatures well. However, constant heat exposure can cause negative effects, stressing your roof, breaking it down faster, and reducing its lifespan.
In addition, a scorching-hot 75˚C roof in the sunshine can cool to 10˚C in the night. Sixty-five degrees from day to night is quite a temperature fluctuation! Variations in temperature, with hot days and cools nights, can put your shingles to the test. This is called thermal shock. High temperatures expand your roofing materials during the day, and cooler temperatures contract the materials at night. Constant expansion and contraction strain your roof and can cause damage.
The colour of your roofing can create hotter or cooler temperatures, as can the material. Some materials, such as metal, and lighter-coloured roofs reflect the sun’s rays. Other materials, such as asphalt, and darker-coloured roofs absorb the sun’s heat, and radiate it into your home. In colder climates like Alberta’s, it is recommended to have a mid-toned asphalt roof as it is helpful in our long, winter months when the heat is absorbed. However, we do not recommend a black roof as it will cause your home to become unbearably warm during our short, hot summers.
Indoor Comfort on Hot Days
A hotter roof means a hotter interior. To increase your comfort indoors, consider these suggestions.
- Increase your attic and ceiling insulation to keep outdoor heat from coming in.
- Proper attic venting allows hot air to escape from your home.
- Plant a fast-growing deciduous tree. In summer, when you want things cool, a deciduous tree’s leaves will shade your home and roof. In winter, when you want the sun’s warmth, the leaves disappear and allow the sun to shine through.
- As a short-term quick-fix, some people spray their roofs with water. We don’t recommend this, as the good effects don’t last long enough to effect temperature change, and will only increase your water bill.
Maintenance and Protection
In the fall, inspect your roof after many days of cooler temperatures. Look for signs of melted materials near joints and shingle seams. Also look for cracking due to temperature fluctuations and thermal shock. Please do not go onto your roof after hot weather. Your weight on heat-softened materials could damage it.
Twice-yearly inspections are recommended to help you “stay ahead of the game” and mitigate damage while it is still small, making it easier and less expensive to repair. Book your inspections with us as part of your home’s regular maintenance. Remember, your roof is the biggest heat shield and the main water shield of your home.
Generally speaking, new roofs perform better in high heat than older ones. Aging roofs lack new technologies and improvements that your home could benefit from, plus, due to their age, old roofs are more prone to warp, buckle and erode. Consider replacing your roof, especially if has been 15 years or more since you last did.
Contact us for a quote. We’d be happy to hear from you!