Even good quality asphalt shingles won't keep the water out of a house if they've been applied improperly, or if important details have been overlooked. On an inspection of a three-year-old roof, Mark Parlee immediately spotted problems that were causing leaks, related not to the shingles themselves but to how the shingles or the flashing had been installed. Among the problems:
- No new step flashing, and no effort to integrate new shingles with existing flashing.
- Inadequate offset between courses of shingles.
- Haphazard nailing patterns.
- No drip edge on any of the roof edges.
- No boots over plumbing vents.
The roof had so many problems Parlee could only recommend it be removed and completely replaced. Although most roofs don't share all of the problems found here, many roofing jobs suffer from one or two of them -- and it only takes one to cause a leak.