Valley leaks
Where two roof slopes meet
Flashing is what seals every junction on a roof — walls, chimneys, valleys, penetrations — and it is where most leaks begin. It fails through corrosion, through movement opening the joint it was set into, and through having been installed as a surface detail rather than stepped properly into the courses. Replacing it means working into the surrounding material rather than sealing over the top, which is why it costs more than a patch and why it lasts.
Great Neck sits on a barrier-adjacent island where three things attack a roof at once. Salt air corrodes every metal component up there — flashing, fasteners, drip edge, vent collars — so the parts meant to outlast the shingles frequently do not, and most leaks here turn out to be metal failures rather than shingle failures. Nor'easters bring sustained wind with rain driven sideways, which gets under courses that would shed any amount of vertical water. Then winter adds ice damming at the eaves, where meltwater running down a warm roof refreezes over the cold overhang and backs up beneath the shingles. Housing stock across Nassau County runs older than the national average, with a lot of complex roof geometry, dormers and additions — and every junction is another place flashing has to work.
Great Neck has a population of about 11,145, and the housing stock here sets the pattern for what fails first on a roof.
It is thinner material in the most exposed position, and it sits across a joint between two things that move at different rates. On most roofs the flashing is the first component to need attention, often by a decade.
Yes. It means lifting and reinstating the surrounding courses, but it is a localised job on an otherwise sound roof and far cheaper than replacement.
Where two roof slopes meet
Ponding, seams and parapet flashing
Fasteners, washers and seams
Damp insulation, dry ceiling
The boards behind the gutter
Cedar shake roofs
You will get a straight answer on whether Great Neck needs someone out today or whether it can wait — before anyone quotes you for anything.
Call (706) 696-1888