Do you have a screen porch or covered deck or patio? Have you found that periodically the roof will leak when it rains but only occasionally? There are several potential explanations for this.
If the roof was properly constructed with the appropriate felt paper, flashing, valleys, ridge, etc…this can still happen! The reasons vary but are most likely one of two issues. At times, individual shingles can be damaged by something hitting them (hail stone, football, etc…) and they begin to curl up and allow moisture to penetrate. Secondly, a driving or sideways rain can make it appear the roof is leaking when it is in fact not. the rain can come in from below the header and make it appear that the ceiling is wet from above. Thirdly, even when roofs are flashed, sometimes the silicone or caulk loses it adhesive from weather wear and tear and simply needs to be resealed. For more information and even repair work, go to charlotte.archadeck.com