Roof repair glossary
Atmospheric river
A long band of moisture in the atmosphere that can bring prolonged heavy rain and wind to Northern California.
C-39
The CSLB license classification for roofing contractors in California.
Class A roof
The highest fire-resistance rating for a roof assembly under standard fire tests. California's WUI code requires a Class A roof assembly on new buildings in designated fire hazard zones.
Drip edge
Metal edging at eaves and rakes that directs water into gutters and away from the fascia.
Fire Hazard Severity Zone (FHSZ)
An area CAL FIRE has mapped as Moderate, High or Very High fire hazard. Your zone can affect building requirements.
Flashing
Thin metal (or other material) that seals joints where the roof meets walls, chimneys, skylights, vents and valleys.
Pipe boot
The collar that seals around a plumbing vent pipe where it passes through the roof. Cracked boots are a common leak source.
Roof deck (sheathing)
The plywood or boards the roofing is fastened to.
Standing seam
A metal roof system with raised, interlocking seams and concealed fasteners.
Underlayment
The water-resistant layer installed between the roof deck and the roof covering.
Valley
The channel where two roof slopes meet. Valleys carry a lot of water and collect debris.
WUI code
The California Wildland-Urban Interface Code, Title 24, Part 7, which sets wildfire-resistant building standards, formerly in Chapter 7A of the building code.