Roofing Glossary: Common Terms Explained
Roofers, adjusters and manufacturers all use their own shorthand. Here's what the common terms actually mean, without the jargon.
A – D
- ACV (Actual Cash Value)
- An insurance payout method that factors in depreciation for the age and condition of what's being replaced, as opposed to its full replacement cost.
- Algae streaking
- Dark streaks on a roof caused by a type of airborne algae (Gloeocapsa magma), common in humid climates like Houston's, mostly cosmetic but linked to shortened shingle life if left unaddressed.
- Attic ventilation
- The system of intake and exhaust vents that lets air move through an attic, controlling heat and moisture buildup under the roof deck.
- Decking (roof deck)
- The structural wood layer, usually plywood or OSB, that shingles and underlayment are attached to.
- Deductible
- The amount a homeowner pays out of pocket on an insurance claim before the carrier's coverage applies.
- Drip edge
- A metal flashing installed along roof edges that directs water away from the fascia and into the gutter.
E – L
- Fascia
- The vertical board that runs along the edge of the roofline, usually where gutters are mounted.
- Flashing
- Thin metal installed at roof joints, valleys, chimneys and penetrations to redirect water away from vulnerable seams.
- Granules
- The mineral coating on the surface of asphalt shingles that provides UV protection and color; granule loss is a sign of aging or damage.
- HOA approval
- A sign-off some homeowners associations require before a roof replacement, often governing shingle color or material within a community.
- Hurricane season
- The period from June 1 through November 30 when tropical storm activity is most likely along the Gulf Coast.
- Ice and water barrier
- A self-adhering underlayment used at vulnerable areas like valleys and eaves for extra protection against wind-driven rain.
- Ledge/step flashing
- Individual pieces of flashing woven into shingle courses along a wall or chimney to shed water in layers.
M – R
- Manufacturer warranty
- Coverage from the shingle or system manufacturer against defects in the materials themselves, independent of who installed the roof.
- Modified bitumen
- A low-slope commercial roofing material made of asphalt reinforced with modifiers for flexibility and durability.
- Nail pops
- Roofing nails that back out of the decking over time, often visible as small raised bumps under a shingle.
- Pitch
- The steepness of a roof, usually expressed as a ratio like 4:12 (4 inches of rise for every 12 inches of run).
- Ponding water
- Water that collects and sits on a low-slope roof for an extended period instead of draining, a common issue on flat commercial roofs.
- RCV (Replacement Cost Value)
- An insurance payout method that covers the cost to replace damaged property without deducting for depreciation, sometimes paid in two stages.
- Ridge vent
- A ventilation component installed along the roof's peak that allows hot attic air to exhaust continuously along its length.
S – Z
- Scope of loss
- The itemized list an insurance adjuster prepares describing what will be repaired or replaced and at what cost, following an inspection.
- Soffit
- The underside of a roof overhang, often ventilated to allow intake airflow into the attic.
- Starter strip
- A specialized shingle product installed along roof edges before the first course of field shingles, designed to seal and resist wind uplift.
- Steep-slope roofing
- Roofing systems, typically shingles or tile, installed on roofs with enough pitch that water sheds quickly rather than pooling.
- Supplement
- An additional item or cost submitted to an insurance carrier after the initial scope of loss, when something genuinely necessary was missed.
- Tear-off
- Removing existing roofing material down to the deck before installing a new roof, rather than layering over it.
- TPO
- Thermoplastic polyolefin, a reflective single-ply membrane commonly used on low-slope commercial roofs.
- Underlayment
- A water-resistant layer installed between the decking and the shingles, providing a secondary barrier against moisture.
- Valley
- The internal angle where two roof slopes meet, directing water down toward the gutters; a common site for flashing and leaks.
- Ventilation intake/exhaust
- The paired system — intake typically at the soffit, exhaust typically at the ridge — that allows continuous airflow through an attic.
- Workmanship warranty
- Coverage for how a roof was installed, provided by the contractor rather than the material manufacturer.
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