AIn most cases, roofing problems are discovered after damage has occurred from a leak. However, not all leaks produce visible damage immediately. Some leaks can occur for months or year before visible damage is seen. To avoid this hidden problem, it is important to have your roof inspected periodically and especially after harsh weather events by a qualified roofing contractor. Periodic inspections often can uncover fractured, cracked, warped or missing shingles; it can also reveal deteriorated matting, inadequate flashings and penetration failures. If you see excessive shingle granules accumulating in the gutters or at flowerbeds where downspouts are, then it would be good to call a roofing expert because this could be a sign of potential roof problems. There are other visible signs of roof problems that show up on the interior such as cracked paint, discolored drywall and moisture buildup in ceilings etc… On low slopes you may notice cracks or holes in the seams of the roof or flashing, exposed nails are another place where water can get in and cause damage.