I am a homeowner who selected the GAF Slateline shingles to be installed on a new home construction.
The home is a two story home with the upper roof shedding water onto the lower roof both with shingle drainage and valley drainage onto the lower roof.
In two sections where the valley drainage sheds water onto the lower roof, the water drains to the lower roof at a 90 degree angle so that the water hits the lower shingle from the side rather than from the top of the shingle.
In these two areas, we have had roof leakage both under the shingles and at the side wall flashing.
Numerours repairs, ice and water shields, nail cement, new flashing, new roof deck (rot) have resulted in what appears to be a dry roof for now.
GAF says there is no manufacturer’s defect in their shingle.
The contractor and the roofing subcontractor both say the shingle is defective due to the center “key” allowing water to enter when the upper water hits the lower shingle at a 90 degree angle.
An independent third party, who is also a Master Certified GAF installer, says installing gutters to keep the water from hitting the lower shingle with such force should solve the problem. (He inspected the property twice)
The builder’s warranty is still in effect and has both a workmanship and material’s defect paragraph.
Any opinions on whether I should try the gutters first or simply replace the entire shingle system?
If gutters are chosen, who should be responsible for payment of the gutters? Homeowner or roofer/contractor to solve a leakage problem?