Asphalt roofs are designed to keep rain from getting under the layer of shingles and coming in contact with the wood deck. When rain seeps under the roofing through cracks or holes, it's just a matter of time until water damage occurs. Sometimes, dampness in your attic on the underside of the roof can cause problems too. Here are four ways moisture can get on your roof and cause problems.
1. Rain Leaks Cause the Deck to Rot
Your roof is made up of a plywood or wood deck and topped with underlayment and shingles. When the shingles wear out and it's time for a new roof, the deck doesn't have to be replaced unless it has rotted areas.
The deck might get wet when a shingle has a crack or when a nail falls out of a hole. Rain can also leak in due to rats gnawing on the roof or when gutters are clogged and water backs up under shingles.
When the deck gets wet, it slowly decays and gets spongy. It can be dangerous to walk on then, and once the wood decays, water will leak in your attic. A roofer can repair a rotted deck by cutting out the bad plywood and patching in new material. After that, new shingles are put on to stop the leak.
2. Mold Can Make Your Roof Ugly
Mold can grow on the deck or on top of the shingles. Mold may not harm your roof, but it can create ugly black stains. A roofer can remove mold from asphalt shingles, but it's also important to correct the problem that's causing your roof to hold moisture.
It's also important to distinguish between mold, algae, and moss. Moss will hold moisture against the roof and cause the shingles to decay faster, so moss should be removed as quickly as possible.
3. Condensation Leads to Rotting
Moisture problems in the attic cause further rotting of the roof. Moisture might build up in the attic if a bathroom vent releases warm, humid air in the attic. Any leak from your living space below allows warm air to rise to the attic roof and cause condensation. If the problem goes on long enough, the roof, which is the underside of the roof deck, can start to rot. This can also lead to mold that circulates through your home. To fix this problem, you'll need to block warm air from entering your attic. You may need a mold removal professional to clean mold from the attic and a roofer to replace rotted roof sheathing.
4. Rotting Leaf Clumps Trap Moisture
Another way your roof can develop moisture problems is when leaf clumps get caught in a valley. When the leaves stay damp a long time and begin to decay, they affect the shingles and deck underneath them. Leaves should always be removed if they don't blow off on their own, or you might need to have shingles or part of the deck replaced.