Causes

• Most roof leaks are caused by poorly installed, damaged or deteriorated flashing around the chimney, plumbing vents or head wall vents. Cracked or torn roof shingles may leak if a nail is exposed or the shingles in the valley are not cut correctly. Weather-related problems such as an ice dam or strong winds force water from the roof into a wall cavity.
  
  

Inspection

• Locating a roof leak is a challenging venture. Gravity may direct leaking water several feet from the original source. Tom Silva of This Old House recommends inspecting the roof flashing from the underside of the roof, in the attic, before attempting a wide-scale roof replacement.
  
  

Considerations

• Use binoculars to safely inspect the roof from the ground. Walking atop a steeply pitched roof is extremely hazardous. If you are hesitant to clamber onto the roof yourself, hire a professional to inspect the roof flashing and shingles.