• If you have water coming through your ceiling, you could have a roof leak.Michael Blann/Digital Vision/Getty Images
  
  The rhythmic drip-drip of a leaking roof can mean serious damage to the interior of your house when it rains. Leaks that occur in roofing material are not uncommon, and the leak generally happens in the same few ways. If you have noticed wet spots on your ceiling, there are a handful of places on the roof where the water is likely to be seeping through. Knowing the different types of roof leaks may help you diagnose the problem easier and pinpoint where the repairs need to happen.
  
  

Shingles

• One of the most common roof leaks is a leak in the field of shingles spread across the roof. This type of leak is more difficult to pinpoint because the source of the leak could be anywhere in the general vicinity of the interior drip. Think about the natural flow of water to help narrow down the location. The cause of the leak is possibly that a nail has backed out of a shingle and simply needs to be tapped back in. Wind could also have blown shingles off and left a leak, in which case they'll need to be replaced.
  
  

Valleys

• If the flashing of the roof isn't installed just right, or if it becomes dislodged somehow, leaks are likely to occur in the places where water accumulates the most during rain. The valleys of the roof sections where water flows down into the gutters for drainage could be the source of this kind of leak.
  
  To prevent future leaks in the valleys of the roof, the flashing needs to cover the valley completely and must be made of a durable material like metal or there should be rolled roofing to cover the valley completely. If the roof valleys are stitched shingles, the shingles must be trimmed correctly to prevent water from getting under one of the shingles and forming a leak.
  
  

Chimney

• Any area where the roof shingles meet an area where another object protrudes through, there is a good opportunity for a leak to develop. The chimney is one place where this commonly happens. Cracked cement, old caulking or damaged flashing can cause a leak here, making it one of the most leak-prone areas of the roof. Peeling off old caulking or chipping away cracked cement and putting down new material will probably fix the problem. Flashing problems are also easy to remedy through replacement.