A roof in Edinburg came up on our list because the homeowner’s insurance company wrote to them and said it had to be replaced. The roof is eleven years old. It was sold as a 30-year roof. And when you get up on it, the shingles look like someone worked them over with a hammer.
That look gets called hail damage constantly. On this house it is not hail. It is the attic.
What blistering actually is
A shingle is asphalt with granules pressed into the surface. Asphalt holds a small amount of moisture and gas. Heat it hard enough from underneath and that expands, lifting the surface into raised bubbles. The bubbles eventually break open and take the granules with them, leaving small craters across the roof.
The heat comes from the attic. Every attic needs intake venting low down and exhaust venting up high, sized to the square footage, so air moves through continuously. When those numbers are never calculated — and on a cheap roof they often are not — the attic holds heat all summer. In the Rio Grande Valley that is a long summer.
How to tell it apart from hail
- Look at the soft metals. Hail that is big enough to damage shingles also dents vents, flashing, gutters and the mailbox. Clean metals with a chewed-up roof points away from hail.
- Look at the pattern. Hail is random and directional, usually worse on the slopes that faced the storm. Blistering is spread evenly and tracks where the attic is hottest.
- Look at the shape. Blisters are round craters with soft edges. Hail hits are bruises, often with a shiny spot where the mat is exposed.
This matters because the two have completely different answers. Hail is a claim. Blistering from a hot attic is an installation problem, and no claim is going to cover it.
What else was wrong on this roof
The venting was the headline, but it was not alone. The first course at the eave was leftover field shingles turned upside down instead of a real starter strip, so the bottom edge never sealed properly. The drip edge was installed so that you could see the metal from on top of the shingles, which lets water wick back over it and into the soffit and fascia instead of running off. Both of those are the same story as the venting: the cheapest way to get the job done.
We see the starter strip problem constantly — there is a whole video on what it does to the edge of a roof.
If your roof is young and already looks old
A 30-year roof that is finished at eleven was not a bargain. If your shingles are cratered, if the ridge line has faded early, or if your insurance company has sent you a letter, it is worth having someone get in the attic as well as on the roof.
A roof inspection from Frontline Roofing is free and you get photos of what we find. Call or text (956) 586-5711. We cover McAllen, Mission, Edinburg and the rest of the Rio Grande Valley, and we handle roof replacement and insurance work.
Watch the full walkthrough: why the insurance company says this 11-year-old roof has to go. More on the Frontline Roofing video page.