Q: Why is my roof leaking? A: Leaking roof: Normal weathering of asphalt roofing shingles will not cause leaking. Causes: Flashings are crucial areas that must be watertight to avoid leaks. These are the areas most frequently identified as the causes of leaks. Damaged shingles leave the roof exposed to leaks and should be repaired without delay. When installing shingles take note of the alignment of the cutouts, depending on the type of BP shingle chosen, as well as the nailing location as these areas are crucial to the ease with which water can infiltrate a roof. They should always be covered by overlying shingle tabs. Inadequate ventilation can cause ice damming, frost and condensation accumulation. These problems can all be easily prevented with proper air circulation.