Serious Water Damage
Water can heavily damage any roof. Water damage is an indication that something is seriously wrong and needs to be replaced as soon as you can. If you see areas inside that have obvious water damage, this is an indication that the roof has suffered major damage. Signs of water damage can include brown patches where there were none before. You may also see peeling paint or even areas of obvious green mold.
Natural disasters can have a huge impact on the state of the roof. Even a relatively low pass from a hurricane can linger for hours and cause shingles to fall off. A tornado can hit and immediately damage the entire roof structure. Other natural disasters can cause problems for an entire neighborhood in the space of a day. The same is true of other kinds of weather conditions. Ice and snow over a long winter can easily damage the entire roof. The homeowner should look at the structure in the aftermath of a harsh winter and see what has been done.
The Age of the Roof
In general, a roof is good for a certain number of years. As the roof ages, it may be approaching the end of its useful life. The homeowner should know when the roof was put on when they bought the house. They should also know if efforts have been made to repair the roof before they purchased the home. A good home inspection can reveal approximately when the roof was created and what additional efforts have been made to repair it. The homeowner can then decide if it makes sense for them to have the entire structure replaced rather than repaired again.
Different types of material are used in creating a roof. These different types of materials will all have different lifespans. For example, if the roof is made from asphalt shingles, these generally last about three decades before it might be necessary to replace the entire structure to fix it. The second layer of shingles may have been added to extend the life of the roof and they may also be reaching the end of their useful life. The roof might be made from other materials such as wood shingles that also have a specific lifespan.