Philadelphia averages 30 freeze-thaw cycles per winter. Ice forms in the gaps between skylight flashing and shingles, then melts, then refreezes. This cycle expands and contracts the metal flashing, breaking sealant bonds and creating micro-gaps. When spring rains arrive, water infiltrates these gaps. The problem worsens on north-facing roof planes, where ice lingers longer and freeze-thaw cycles are more frequent. Proper flashing installation with ice and water shield protects against this seasonal stress, but older skylights installed before modern codes lack this protection.
Philadelphia's roofing landscape includes historic districts with strict architectural guidelines and rowhomes with shared roof valleys. Skylight repairs in these homes require knowledge of local construction methods and materials. Atlas Roofing Philadelphia works with the city's building codes and understands the requirements for permits and inspections. We coordinate with historical societies when working in protected neighborhoods. This local expertise ensures your skylight repair meets code, preserves the architectural integrity of your home, and does not create problems with your neighbors or the city.