When shingles have worn out and lost their granules, the reinforcing mat inside the shingle contracts, which causes the shingle to curl. If you have signs of curling you should have your roof inspected. Roofs with a lot of curling need to be replaced. They not only look bad, but can leak and blow off, among other issues.
Improperly installed, or old shingles may blow off in wind storms, leaving your roof vulnerable to leaking. Often times the missing shingles can be replaced and other loose or unsealed shingles can be glued back down.
Widespread cracking in shingles can be caused by an under-vented roof, age, or even a manufacturers defect.
AS a shingle ages, naturally it will loose granules. You will notice dark spots where the colored granules are missing and the tar is exposed, or the shingles will have spots that glimmer in the sun. This is where the fiberglass is exposed. Some people will notice an excessive amount of granules in rain gutters, or coming out of downspouts.
Of course a major part of a good roof is what is underneath the shingle, a solid plywood deck is a must. Part of a good roof inspection and estimate should be a visual inspection of the roof, looking for any waves or lumps. Putting some weight in several spots on the roof and listening for cracking is also an effective way to test the plywood’s strength. If the plywood cracks it is a sign of the attic being overheated for a long time, this is due to an improper ventilation system. Unfortunately when this is the case, there is a good chance the roof will need a lot, or all new plywood.
Of course roof leaks are a sign that you might need a new roof. You might see signs of dripping through the soffits on the eaves of the house or water penetrating the ceiling on the inside of the house. It is so important to have roof leaks fixed right away. Over time the water damage can cause damage to sheet rock, stucco, siding, soffits, and even structural issues. In some cases, the water penetration can cause mold to grow. Mold can be a very dangerous health concern.