Surviving Summer

Jul 8, 2019 | Roofing

Will Your Shingle Roof Survive Summer Heat?

Check Attic Ventilation

Quality brand name shingles should have no problems in protecting your home under normal conditions. But if vents have become blocked, or fans no longer work, heat can build up quickly below the shingles, turning your attic into a hot box. If the temperatures exceed manufacturers’ expectations, shingle performance could suffer. Should you have any concerns about your roof’s ventilation system, be sure to contact a professional.

Blistering Shingles

There are two primary reasons for asphalt shingles to blister. The first is moisture that could have been trapped within the shingles themselves. As the roof heats under the sweltering summer sun, trapped moisture can expand, causing blisters to rise. The second is poor ventilation. As already covered, inadequate ventilation in the attic can allow the roof to become too hot for the shingles.

If you encounter blisters on your shingles you’ll want to keep an eye on them. As long as the blisters on the shingles retain their granules, the condition may not impact the longevity of the roof. The size of the blisters will often go down as the roof cools.

If the blisters pop, granules can become dislodged, resulting in asphalt areas that are unprotected from the harsh UV rays of the sun.

If you see blistered shingles, it’s best to avoid walking on them. Falling debris can also bring harm to blistered shingles. Check the surrounding trees and cut back some of the limbs. This could prevent branches, pine cones, and acorns from falling on the shingles.


Hail damage can often look just like blister damage. If blisters have popped due to human weight, they will generally be limited to areas of foot traffic. Hail damage, on the other hand, will be far more uniform. If granules have been lost due to hail strikes, the roof’s defense against the sun and weather could have been compromised. Should your roof endure a hail storm this summer, it’s a good idea to have it professionally inspected for storm damage.

Granule Loss

Granule loss from asphalt shingles can seriously impact both the performance and lifespan of the roof. Granules are adhered to the surface during the manufacturing process and protect the asphalt shingle from the damaging effects of UV light and local weather conditions. These granules also reflect light, keeping your home cooler during the summer months.

We’ve already discussed several of the causes of shingle granule loss: blisters that have popped, mechanical damage from foot traffic, and hail. If you’ve had work done on the chimney, or the gutters cleaned, it’s a good idea to check for signs of wear. Another form of mechanical damage can result from tree branches too close to the roof’s surface. Curled shingles can flap about in a storm. Even if they don’t break in the wind, sometimes they will shed many of their granules.

Note: A brand new shingle roof will shed loose granules for a while, so finding granules in the gutters may not be cause for alarm. Roofs will also lose granules due to normal aging. Weather, dramatic temperature changes, and sun exposure cause the shingles to lose their flexibility over time, resulting in a breakdown of the adhesive properties keeping granules in place.

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