How to Beat the Heat: Summer Temperatures & Your Roof

While you’re sweating through those hot summer days, your roof temperatures can skyrocket. Find out what factors affect your roof’s temperature and how keeping a cool roof can protect your home (and save you some money)!

Most Canadians worry about their roof in the winter and spring, when high winds, heavy snow, and freeze/thaw temperature fluctuations can cause some serious damage. 

Summer maintenance isn’t usually a top priority, but maintaining your roof’s integrity is a year-round commitment. Homeowners should also be aware of how the summer can affect their roofs. With hot weather and heat waves causing roof temperatures to jump to 60-88°C, maintaining your roof through the summer can help keep your home cool and prevent thermal shock. 

Learn more about summer heat effects and how to cool your roof in our guide below.

How Summer Heat Affects Your Roof

As Hamilton roofing contractors, we know that Canadian summers can get hot and sticky quickly. Between UV light, humidity, and more, the stress can sometimes cause structural issues on your roof. 

High Temperatures

Though trees sitting too close to the roofline can drop twigs, branches, and debris on your home, they also provide some much-needed shade on a hot 30° day, when your dark-shingled roof gets even higher than the temperature of the air. Extreme heat causes your roof’s materials to break down more quickly, affecting its overall lifespan. 

UV Light

Ultraviolet light causes damage to most surfaces it hits - that’s why we need to wear sunscreen. UVs are at their strongest in the summer, and though shingles are made of tougher materials than our skin, you may see colour fading, buckled, split, or peeling shingles. Your roof contains protective oils that can dry out during hot summer months, making it more prone to breakage.

High Humidity

Humidity isn’t just uncomfortable for us - it brings moist air in and around your roof, where it can condense under the shingles or in small cracks or gaps between materials. Unfortunately, that moisture often stays put, leading to leakage, water damage, or the development of harmful mold.

Thermal Shock

Ontario is known for its weather extremes - something our team of roofers in Hamilton, Ontario, knows all too well. While temperatures can skyrocket during the day, they often drop significantly in the evening. These big fluctuations cause materials in your roof, like wood or underlayment, to quickly expand and contract. That added pressure creates tension on the materials, which may weaken your roof’s integrity and permanently warp it. 

How to Protect Your Roof From the Heat

Roof quality doesn’t need to be compromised by summer heat. Try these tips and tricks to reduce your roof’s heat, protect your investment, and lower your A/C costs significantly. 

#1: Try a White Roof

Light-coloured roofing systems, like light-coloured clothing, stay cooler because they reflect more light. White roofs with cool roof shingles absorb less heat, naturally keeping your home and the rooftop itself much cooler than traditional dark shingles. 

White roofs tend to last twice as long as black roofs because of their heat-reflecting properties - you’ll typically see longer warranties, fewer repairs, and less maintenance if you invest in one. 

Since metal roofs are more energy-efficient and often come with factory-applied cool coatings, you can double down on your roof’s cooling properties by investing in a white metal roof.

#2: Add a Cool Roof Coating

Not ready to replace your current roof with a white one? You can paint an existing dark roof with cool roof paint or a reflective roof coating, effectively upgrading your system to lengthen its lifespan. After painting, your reflective shingles have a solar reflectance index (SRI) of up to 90% - that’s some serious cooling power. 

You can find heat-resistant paint for roof cooling in two main categories:

• Cementitious coating contains ceramic or concrete particles to improve solar reflectance. 

• Elastomeric coating works as a watertight membrane to make your roof less brittle. 

Both work wonders to cool your home and roof, but while elastomeric coatings work independently, cementitious coatings are only effective if your roof underneath is already adequately waterproofed. 

#3: Plant Some Trees

Planting trees around your home’s exterior cuts the heat off at the source, reducing the UV rays that hit your roof to help it stay cooler. You must be strategic about your tree placement to ensure that they shade your roof without increasing the potential for damage from falling branches, leaves, and other debris. 

If you’re unsure where to plant, consult roofing contractors in Hamilton to discuss your yard’s “safe zones.”

#4: Install a Misting System

A roof misting system can help you keep your existing roof cool without replacing it, thanks to sensors that monitor your roof’s moisture and temperature. Whenever your roof temperature gets too hot, the system sprays some cool water across the affected area to bring it back down to a normal range. As the water evaporates off the roof, the temperature goes down. 

#5: Improve Roof Ventilation

Though the above solutions all work to cool your roof’s exterior, you can cool your roof from the inside out by improving your ventilation system. When your roof and attic have proper ventilation, the air moves freely and keeps your roof and home cooler. Using ridge vents, wind turbines, radiant barriers, and insulation, you can reduce the temperature in your attic by as much as 10°C. 

#6: Try a Single-Ply Membrane

If your home has a low-sloping roof, you can try a single-ply membrane, a cooling sheet for roof protection, in place of the liquid roof coatings we previously mentioned. These single-ply membranes come in vinyl or plastic and contain the same sun-reflecting properties in their coating or materials.

Installers can roll these sheets onto your roof deck and attach them to its structure using chemical adhesives, fasteners, ballast, or a combination. Essentially, you’re cling-wrapping your roof with a heat-resistant coating. 

The most commonly used single-ply membranes are:

• Ethylene propylene diene monomer (EDPM),

• Polyvinyl chloride (PVC),

• Thermoplastic polyolefin (TPO).

Ready to cool your roof?

You don’t have to faint at the sight of your summer utility bills or replace your roof sooner than you should - beat the heat with a better cool roofing solution. 

Our team of Hamilton roofers at Sameday is ready for your call. Let’s discuss cool roofing and book a free cost estimate. Call us at (905) 544-4667 or send a message today.