How old is your existing asphalt shingle roof? Most experts agree that a typical roof will last between 20 and 25 years. It also depends on whether the old roof was removed and you only have one layer of shingles, and if it is properly ventilated. If the roof was installed over another layer or several layers and it is older than 20 years, chances are you need a new roof.
2. Shingles curling and buckling