When you call a roofing contractor to check your asphalt shingle roof for damage, one of the things they may check is the condition of the roof deck. The deck is made of sections of plywood, and the plywood can rot and get weak due to water damage. Finding problems with moisture on your roof is important because the roof could collapse if the deck rots out completely. Here's how roofers check for moisture damage on asphalt shingle roof decks.

Look For Moisture Damage On Shingles

The roofing contractor may start the search for moisture damage by looking at the shingles. If shingles look more worn in one area, or if the edges are curling, that might indicate there is moisture trapped under the shingles that is affecting the roof deck. Fortunately, it's easy to spot deck damage by looking under the shingles. Since you don't want the roofer to lift every shingle, looking for signs of shingle damage is a good way to narrow down the hunt for moisture problems.

Examine The Plywood Visually

When roofers check for leaks on commercial buildings that have flat roofs, they use infrared cameras, moisture meters, or core samples to find moist areas. The images produced by an infrared camera let the roofer know where moisture is hiding under a membrane roof that can't be lifted to see what's under it.

While a roofer might use moisture-detecting equipment on an asphalt shingle roof too, it isn't necessary since all the roofer has to do is lift a few individual shingles to look at the deck. By looking for water damage and pressing the deck to see if it's soft and soggy, the roofer can tell exactly where moisture is a problem and a leak is likely to develop.

As the plywood soaks up rain, the water damage spreads through the deck. The deck could have a much larger area of water damage than you might expect from a small hole in the roof. It's important the roofing contractor finds the edges of the water damage so all the wet plywood is replaced.

Inspect The Inside Of The House

When a roofing contractor is looking for a leak, they'll probably check the inside of your house, including the attic. They'll look for water stains, mold, a musty odor, and wet insulation. They may also examine your living space for water stains on the ceiling and walls. Signs of a water leak in your house let the contractor know the roof has water damage too, and then the roofer has to go to the top of the roof to look for the leaky area and determine how much of the plywood deck is affected so it can be replaced.