What the New Jersey year does to an Irvington roof
New Jersey gives a roof no easy season. The summer here is hot and humid, and the heat that builds in an unvented Irvington attic bakes asphalt shingles from below while the sun cooks them from above. Then the storms arrive. The afternoon thunderstorms that sweep across Essex County in July and August drive rain sideways into anything that is not flashed tight, and the nor'easters that come later in the year stack wind on top of hours of heavy rain. A roof that has been quietly aging all summer suddenly has to shed a serious volume of water under real wind pressure, and that is when the weak spots give way.
Winter brings the slowest and most damaging force of all. When snow sits on an Irvington roof and the attic below is warm, the snow melts, runs down to the cold eave, and refreezes into an ice dam that backs water up under the shingles. The same freeze-thaw cycle that builds ice dams also works on every small crack and gap, prying it open a little wider with each cold snap. The leak that shows up in February was often created by a brittle flashing detail the previous August. That is why we are so insistent on inspecting before the cold sets in, while there is still time to seal up the vulnerable spots before water and ice ever reach them.