Even though your roof is exposed to rain and snow, it's still important to keep the part of the roof underneath your shingles as dry as possible. Shingles tolerate rain on the surface because the rain dries out fairly fast by the wind and sun. Rain that gets underneath the shingles can cause the roof to rot since the moisture doesn't dry out. Here are some signs your roof may be rotting and what your roofer might do about it.
Signs Your Roof Is Rotting
When you check the roof from inside your attic, you might notice dark spots on the bottom of the roof or on the rafters. The presence of mold inside your attic is a sign the roof has been leaking, and that could indicate the deck of the roof has water damage and rot.
If the situation is bad, your roof may eventually start sagging, and that's a dangerous situation since a saggy roof could collapse, especially when your roofer walks on it. A roof that's rotted also has a different feel when you walk on it. Rather than being firm, it feels spongy.
If your roof has moss growing on it, that's a sign your roof could have a moisture problem, and where there is moisture, there could be rotting.
Causes Of Rot On An Asphalt Shingle Roof
Rotting begins when water leaks under the shingles or under loose flashing. The underlayment blocks the water initially, but if the underlayment is worn away or has a hole, water can still get to the roof deck.
Once a leak develops and gets the deck wet, it takes a long time to dry out since the deck is covered. This can cause the deck to mold and rot. Water might get underneath shingles due to anything that can lift the shingles such as wind, moss, and tree branches. Damage to the shingles such as cracks, holes, and missing shingles can also let in rain.
Repairs Your Roofer May Need To Do
The first thing your roofer has to do is find out how large the rotted area is. Your roof could potentially have widespread damage and need to be replaced entirely. However, it's also possible the rotted area is confined to a small portion of the roof. In that case, repairs might be possible.
All the shingles that cover the rotted deck and the underlayment under the shingles need to be torn off to expose the deck. The roofer keeps tearing them off until dry decking is reached. Then the rotted deck can be removed from the roof. Once the deck is out of the way, the rafters can be examined.
If the rafters have rotted, the roofer may need to add another board alongside each rotted rafter to provide support. Then new plywood decking can be applied and nailed to the new rafters. After that, underlayment and new shingles are put on to complete the repairs.
For more information, contact a local roofer.