Building Envelope, Roofing, and Weatherproofing
Building Envelope, Roofing, and Weatherproofing tests water management, flashing, roof assemblies, and air and vapor control in New Jersey's freeze-thaw climate.
Water management
Manage water in layers: roof covering, underlayment, flashing, drainage plane, and foundation drainage. Install drip edge, valley flashing, step flashing at sidewalls, counterflashing, and proper laps so upper materials shed over lower materials. Housewrap and weather-resistive barriers must be lapped shingle-fashion and integrated with window and door flashing. Do not rely on sealant as the primary flashing.
Roofing
Asphalt shingles generally require a minimum 2:12 slope with underlayment; lower slopes need a low-slope assembly. Ice-dam protection is required where the adopted code mandates it, typically along eaves in cold climates. Provide attic ventilation and air sealing so warm, moist air does not bypass insulation and form ice dams.
Vapor and air control
In New Jersey's mixed climate, air sealing is the first defense against moisture movement. Vapor retarders must be placed correctly for the assembly and season; a poorly placed retarder can trap moisture in the sheathing.
Worked example
A roof leaks beside a chimney. The roofer caulks the joint. The actual defect is missing step flashing and a counterflashing reglet. The repair should remove shingles, install a proper cricket if the chimney is wide, weave step flashing with each course, and set counterflashing into the masonry. Sealant alone will fail at freeze-thaw movement.
Traps
Reverse-lapping housewrap; caulking instead of flashing; blocking weep holes in brick; omitting ice barrier at eaves; venting a bathroom into the attic.