How Summer Heat Affects Your Asphalt (And What to Do About It)

Winter gets all the attention when it comes to driveway damage — and for good reason. But summer has its own impact on asphalt that's worth understanding, especially during London's increasingly hot July and August stretches. Here's what heat actually does to asphalt, and how to protect your investment through the warm months.

Asphalt Is Designed to Be Flexible — Until It Isn't

Asphalt is a petroleum-based product, which means it responds to temperature. In winter it becomes hard and brittle; in summer it can soften significantly. On a hot day, the surface temperature of dark asphalt can reach 50 to 60°C or more — well above the surrounding air temperature. At those temperatures, fresh asphalt becomes pliable.

This flexibility is actually one of asphalt's strengths — it can absorb stress and movement better than rigid concrete. But it also means that heavy loads, sharp objects, or even extended parking in the same spot can leave impressions in a softened surface.

Watch for These Heat-Related Issues

Rutting or tracking — When vehicles sit on very soft asphalt, especially near the top of a driveway that gets full afternoon sun, you may notice tire marks or slight depressions. This is most common with newly installed or freshly sealed asphalt that hasn't fully set, and in areas where vehicles regularly idle or turn in place.

Edge softening — The edges of an asphalt driveway — especially where they meet soil — can soften and spread slightly during extreme heat. Over time, this weakens the border and makes the edge more vulnerable to cracking.

Accelerated oxidation — Heat accelerates the oxidation process that causes asphalt to dry out, fade from black to grey, and become more brittle. This is the same process that happens year-round, but UV exposure in summer speeds it up significantly.

Existing cracks expand — Thermal expansion causes the asphalt itself to shift slightly as temperatures rise and fall. Existing cracks can widen during summer heat cycles, which allows more water in when fall rains arrive.

What You Can Do

Avoid parking heavy vehicles in the same spot repeatedly on very hot days. This is especially true if your asphalt is new or was recently sealed. Give it time to re-harden in the cool of the evening.

Consider a quality sealcoat. A good sealcoat applied in spring or early summer does more than protect against water — it slows oxidation, shields against UV damage, and gives the surface a layer of protection during the hottest months.

Fill cracks before summer gets going. Any crack that goes into summer unfilled will be wider by fall. Water that gets in during an August rainstorm sits in the crack and causes more damage.

Keep vehicles with sharp or metal edges off fresh sealcoating. Kickstands, trailers with metal feet, and low-clearance vehicles can all mar a freshly sealed surface.

Summer Is Still a Great Time to Seal

Despite the heat, summer is one of the best times to get sealcoating done. Warm temperatures help the sealant cure properly, and dry weather makes scheduling easier. The key is to choose a day when the forecast stays dry for at least 24 to 48 hours after application.

Lawns & Lanes offers asphalt sealing throughout the summer months. Call us at 226.234.6541 or visit lawnsandlanes.ca to book your appointment.