The Age of the Roof
Most asphalt shingled roofs last about 15-20 years. Nowadays, there are new types of GAF asphalt shingles which last about 30 years (if maintained well). If your roof has numerous leaks, several damaged areas and is close to 15 years old, then you will likely need to replace it.
Number of Roof Layers
If your roof is leaking and already has several layers, you might need a completely new roof. Roofers refer to this as a “complete tear-off.” All the layers are torn off and new wood roof framing is installed. New shingles are then installed. City codes are usually very strict regarding the amount of layers permitted. In most areas, the maximum number of layers is three. Check with a local roofer who will be most familiar with the roofing codes in your area.
Other Signs That an Older Roof May Need Replacement
Missing or Torn Shingles
Torn, damaged or missing shingles are often a sign of other roof problems. Peeling shingles could be caused by poor roof ventilation. Poor ventilation results in warm air escaping through the roof. The warm air can lead to moisture under the shingles and cause them to peel. Mold growth or black spots are also a sign of a moisture problem. Before considering a new roof, make sure that you have enough intake and outtake roof and attic vents.
Condition of Interior Walls
The condition of the interior walls that touch the roof can give many clues about what is going on up on top of the roof. If you notice a significant loss of paint and heavy moisture marks on your walls (and ceilings), then there could be some serious leaks originating on the roof. If you have safe access to your attic, climb up and check for evidence of moisture.
Extreme Weather Conditions
Tornadoes and hurricanes can cause roof damage that cannot be repaired. Structural damage to the roof cannot always be seen. A professional roofer (with experience in repairing and replacing weather damaged roofs) can help determine if you need a new roof.
Is your roof less than 15 years old and suffering from major problems? It could be that it was improperly installed or that faulty materials were used. Many roofs come with warranties for the materials used and some even cover the labor. Check with the roofing company who installed your roof.