Even with faithful roof repair and maintenance, your roof will deteriorate over time. The main reason for the deterioration is the roof’s exposure to the sun’s UV radiation. Here’s a look at how the different parts of your roof are affected.
Asphalt shingles are made of a base layer saturated with asphalt and then embedded with reflective particles. The asphalt reacts to the sun, causing the shingle’s backing to weather more at the exposed edges than in the center. The result is cupped shingles that hold water instead of shedding it, rendering your roof unable to protect your home.
As the asphalt deteriorates, it also becomes less able to resist water. If your shingles contain an organic backing, they may even start to absorb water. If your shingles have started cupping, you are in serious need of a new roof. At this point, it’s time to call in a professional roofing company.
Everywhere your roof is penetrated by a pipe, a skylight, or chimney, your roof is vulnerable to leaking. To prevent leaks, roofers use flashing and sealants to waterproof those areas. Unfortunately, the best sealants can stand up to the sun for about five years and must be replaced fairly often.
Flashing is part of the waterproofing strategy used by roofers to keep roofing penetrations and valleys from leaking. Flashing also deteriorates much more quickly than the shingles. Different types of flashing weather at different rates. Exposure to rain and sun causes the flashing to corrode and fail. Deteriorated flashing is a common source of many roofing leaks.
Underlayment is a sheet of water resistant fabric applied under your roof’s shingles. Called tar paper or roofing felt, this fabric gets its water resistant properties from asphalt and loses its effectiveness over time for the same reason that shingles do, as was mentioned above. Some types of underlayment have no warranty while others are warranted for 10 to 15 years. When reroofing your home, it is important to use the underlayment recommended by the shingle manufacturer to get the full benefit of both.
An improperly ventilated attic can reach temperatures in excess of 150 degrees. The heat of the attic in combination with the heat of the sun beating down on your roof can accelerate the decomposition of the asphalt that waterproofs your roof’s components. When this happens, your roof will deteriorate faster than it should, causing you to need a roof replacement prematurely. Some manufacturer’s warranties are voided in cases where the attic is not properly ventilated.