HAAG Roof Inspector key terms

The angle of a roof surface stated as the ratio of vertical rise to horizontal run, such as 4:12. It determines drainage behavior, material choices, and which installation methods apply.

The incline of a roof expressed as a fraction of total span, often written as 1/4 or 1/3 pitch. Inspectors convert between pitch and slope when describing steep-slope assemblies.

A roof with a slope of 2:12 or less, commonly covered with membrane or built-up systems. Water drains slowly, so seams, ponding, and flashing details demand close inspection attention.

A roof steeper than 2:12, typically finished with shingles, tiles, or metal panels. Faster runoff means underlayment and flashing laps must be checked carefully for water-shedding performance.

A roofing product made of a fiberglass mat coated with asphalt and mineral granules, nailed in overlapping courses. Inspectors check for granule loss, curling, nail pops, and sealant strip failure.

The wearing away of the mineral surfacing on asphalt shingles, exposing the asphalt beneath. Widespread loss suggests age or hail abrasion and shortens remaining service life.

A fastener that has backed out of the sheathing or missed it and now protrudes through or lifts the shingle above. It creates a leak path and a snag point for wind uplift.

A water-resistant layer installed beneath the finished roofing to shed any water that passes the surface covering. Inspectors verify material type, laps, and coverage at valleys and eaves.

A self-adhering waterproof sheet applied along eaves and in valleys to prevent water backup from entering the roof deck. Codes specify how far up-slope it must extend.

A ridge of ice forming at the eave when melted snow refreezes, trapping water that can back up under shingles. It often signals attic heat loss or inadequate ventilation.

The structural surface that supports the roofing assembly, such as plywood, oriented strand board, or structural concrete. Its condition, fastening, and deflection affect everything installed above it.

The panel material fastened over rafters or joists to form the roof deck substrate. Inspectors look for delamination, sagging, rot, and gaps that compromise fastener holding power.

Metal or membrane components that direct water away from joints, penetrations, and roof-to-wall intersections. Improper flashing is among the most common sources of reported leaks.

L-shaped metal pieces woven into shingle courses along a sidewall or chimney to shed water in steps. Each piece must lap the one below and sit behind the wall cladding.

Metal embedded in or attached to a wall or penetration that overlaps the base flashing to keep water out. Missing or loose counterflashing allows water behind the roof membrane.

A metal strip at the eave edge that directs runoff clear of the fascia and roof deck. It also helps resist wind-driven rain and keeps shingles from drooping over the edge.

The finished board along the roof edge that supports the gutter and encloses the rafter ends. Rot or separation here often points to water entry or gutter overflow.

The internal intersection where two roof planes meet and concentrate runoff. Valleys require special lining and correct shingle weaving or cutting to avoid leaks.

Intake and exhaust openings that move air through the attic to control heat and moisture. Poor ventilation contributes to ice dams, condensation, and premature shingle aging.

Moisture that forms when warm humid air contacts a cooler surface inside the roof assembly. It can mimic a leak and cause deck rot or mold if ventilation is inadequate.

A channel at the eave that collects runoff and carries it to downspouts. Detached, clogged, or undersized gutters cause fascia rot and foundation water problems.

A vertical pipe that carries gutter water to the ground or drainage system. Inspectors check fastening, discharge location, and whether water is being dumped against the foundation.

Any object passing through the roof surface, such as a vent pipe, skylight, or HVAC curb. Each penetration needs a properly flashed and sealed collar or curb detail.

A raised framed box around a roof opening or rooftop unit that keeps water away from the penetration. Curbs must be flashed, and their height is often set by code.

A low-slope assembly of alternating layers of bitumen and reinforcing felt, topped with surfacing. Inspectors check for blistering, splitting, and open seams at laps.

A rolled sheet membrane of asphalt modified with polymers such as SBS or APP, applied by torch, hot asphalt, or adhesive. Seam and end-lap integrity are key inspection points.

A roofing sheet such as EPDM, TPO, or PVC installed in one layer over the deck. Inspectors evaluate seams, fastening, punctures, and shrinkage at perimeter terminations.

A metal strip that mechanically clamps a membrane edge at a wall, curb, or roof edge. Loose or missing bars let water migrate behind the membrane.

Standing water on a low-slope roof that remains more than 48 hours after rain. It adds load, accelerates membrane deterioration, and points to inadequate slope or clogged drains.

A fitting that carries water from a low-slope surface into interior piping. Inspectors check strainers, clamping rings, and the seal between the drain and membrane.

An opening through a parapet wall that lets roof water drain to the exterior. Blocked or undersized scuppers cause ponding and can allow water to back up under the membrane.

The low wall extending above the roof edge, common on commercial buildings. Its coping and flashing details are frequent leak points and are exposed to high wind pressures.

The cap covering the top of a parapet wall that sheds water away from the wall. Loose coping can be lifted by wind and can allow water behind the wall flashing.

A raised platform supporting a rooftop mechanical unit above the membrane. Inspectors check curb height, flashing, and whether the unit is secured against wind uplift.

Mechanical units, ducts, and supports mounted on a commercial roof. Their attachment, curbs, and the penetrations they create must be reviewed for both leaks and wind risk.

Upward pressure on a roof caused by wind flowing over and around the building. It is strongest at corners and edges, where failure often begins during high-wind events.

The perimeter strip of a roof where wind uplift pressures are highest. Fastening and adhesive patterns in this zone are typically more stringent than in the field.

The roof area where two perimeter edges meet, experiencing the greatest wind uplift. Inspectors check for concentrated fastening, extra adhesive, and secure edge metal here.

The pulling out of nails or screws under wind or load, leaving the covering unfastened. It is a common failure mode after storms and is checked by probing and lifting shingle edges.

A soft, crushed spot on a shingle where hail has fractured the mat under the granules. It may not be visible immediately but can lead to premature failure and is often confused with wind damage.

The separation of roofing material from the deck due to wind, often seen as curled or missing shingles at edges. Its pattern helps distinguish wind damage from wear or installation defects.