Roof Defects and Performance Issues
Domain 3 tests failure modes: hail, wind, flashing, moisture, ventilation, and installation defects. The exam wants you to distinguish damage from normal wear and to connect a symptom to its likely cause.
Common defects
- Hail: granule loss, bruised or shiny spots, cracked mats. Damage is random and may be corroborated by dents on metal vents. Blistering is raised and bubbled, not impact-shaped.
- Wind: missing shingles, lifted tabs, broken seal strips, creased tabs. Check ridges, hips, and perimeters first.
- Flashing: missing step flashing at sidewalls, counterflashing not embedded, missing kickout flashing at wall-roof intersections, open valleys.
- Moisture: ceiling stains, rot, mold, efflorescence. Ice dams form from heat loss and poor ventilation; ponding occurs on low-slope roofs.
- Ventilation: intake soffit vents plus exhaust ridge or static vents; blocked soffits defeat the system.
- Installation: exposed fasteners, overdriven nails, poor stagger, insufficient overlap, damaged boots.
Worked example
A ceiling stain appears below a sidewall. Shingles look intact. The likely cause is missing or improperly lapped step flashing, or counterflashing that is not embedded in the masonry. Water runs down the wall, behind the siding, and into the roof assembly. Caulking alone is not a repair; the flashing must be rebuilt and a kickout installed where the roof edge meets the wall.
Traps
Do not call all granule loss hail. Do not confuse blisters with hail hits. Do not ignore kickout flashing. Do not assume a stain means an active leak today; report it as evidence of moisture intrusion and recommend evaluation.