Roofing has its own vocabulary, and a lot of it sounds jargon-y until you build something. This glossary covers the roofing terms (or roof terminology, as it is more formally called in trade publications, or sometimes simply roof definitions) that you will hear from contractors, see on permit drawings, or run into on shingle packaging — defined in plain language with cross-references to the relevant calculator or guide on this site. Whether you are looking up roofing terms and damages after a storm, roofing terminology with pictures for a permit application, roofing terms and pictures for general reference, roofing structure terms for a framing project, or basic roofing terms and definitions for any roof project — the glossary below covers the most common 100+ terms organized by category.
Terms are grouped roughly by topic — framing, materials, components, finishes — and listed alphabetically within each group. Use the on-page search if you are looking for a specific term.
Framing terms
These terms describe the wood (or steel) skeleton of the roof — the structural members that carry load.
- Common rafter — a sloped framing member running from the wall plate up to the ridge. Most rafters on a typical roof are common rafters.
- Hip rafter — a sloped member running diagonally from a corner of the building up to the ridge end. Used on hip roofs.
- Valley rafter — a sloped member at the inside corner of two intersecting roof planes, running from the wall plate up to where the two ridges meet.
- Ridge board (or ridge beam) — the horizontal member at the peak of the roof that the upper ends of all common rafters butt against. A ridge beam is structural; a ridge board is non-structural.
- Top plate (or wall plate) — the horizontal lumber at the top of a wall, on which the rafters bear. Usually doubled in residential framing.
- Bird's mouth — a notch cut into a rafter where it meets the wall plate. Composed of a horizontal seat cut and a vertical heel cut.
- Plumb cut — the angled cut on the upper end of a rafter that meets the ridge. Cut at 90° minus the pitch angle from the rafter's long axis.
- Tail cut — the cut on the lower end of a rafter, past the bird's mouth, that forms the eave. Can be plumb (vertical) or square.
- Run — the horizontal distance from the wall plate to the centerline of the roof. Half the building's span on a symmetrical gable.
- Span — the total horizontal distance the roof covers, plate to plate.
- Rise — the vertical distance from the top of the wall plate to the ridge.
Roof shapes
Different roof shapes serve different functions. Most homes are built with one of these basic forms or a combination of them.
- Gable — a simple two-plane roof with two sloping surfaces meeting at a horizontal ridge. The most common residential roof shape.
- Hip — a roof with four sloping planes, all meeting at a central ridge or peak. No vertical gable walls.
- Shed — a single-plane roof, like one half of a gable. Common on additions, sheds, and modern designs.
- Mansard — a double-pitched hip roof, with a steep lower slope and a much shallower upper slope. Originally French, used to add a finished attic floor.
- Gambrel — a two-pitch gable roof, similar to a mansard but with gable ends rather than hipped ends. The classic barn roof.
- Saltbox — an asymmetrical gable, with one slope much longer than the other. Originally a New England Colonial form.
- Flat — visually flat, but actually slightly pitched (1/4 to 1/2 inch per foot) for drainage. Modern membrane systems handle nearly flat surfaces.
- Butterfly — two slopes meeting at a low central valley rather than a high ridge. Modernist design, requires careful drainage detailing.
Material terms
These terms describe the layers of material that make up the actual weather barrier.
- Asphalt shingle — a flexible mat of fiberglass coated with asphalt and granules. The dominant residential roofing material in North America.
- 3-tab shingle — a flat asphalt shingle with three tabs cut along its lower edge. Less expensive and shorter-lived than architectural shingles.
- Architectural shingle — a thicker, multi-layer asphalt shingle without visible tabs. Most modern residential roofs use these.
- Metal panel — long sheets of formed steel or aluminum used as roofing. Standing-seam panels have raised vertical seams; corrugated panels have repeating ridges.
- Underlayment — a water-resistant layer between the deck and the finish material. Felt (15 or 30 lb) or synthetic.
- Ice-and-water shield — a self-adhering rubberized membrane applied at eaves and valleys to prevent ice-dam leakage.
- Drip edge — a metal flashing along the eave and rake that directs water away from the fascia.
- Starter strip — the first course of shingles installed along the eave, providing a sealing surface for the second course.
- Ridge cap — special shingles or caps that cover the ridge and hips, sealing the joint where two roof planes meet.
- Flashing — sheet metal pieces that seal joints around chimneys, skylights, walls, and other roof penetrations.
Measurement and ordering terms
These terms come up when you are estimating, ordering, or paying for a roof.
- Square — 100 square feet of roof surface area. The standard unit for ordering shingles, underlayment, and labour.
- Pitch — rise over a fixed run of 12. A 4/12 rises 4 inches per 12 inches of run.
- Slope — rise divided by run, often expressed as a percentage. A 4/12 pitch is a 33.3% slope.
- Slope factor (or roof multiplier) — the ratio of actual roof surface to footprint. Multiply footprint by slope factor to get surface area.
- Linear foot — 1 foot of edge length, used for ridge cap, drip edge, and starter strip.
- Bundle — a packaged unit of shingles, typically covering one-third of a square (33.3 sq ft).
- Square footage — the total area of the roof surface, used to calculate material quantities.
- Tributary width — the horizontal distance a beam or rafter is responsible for supporting. Used in structural sizing.
- On-center spacing (OC) — the distance between framing members measured center-to-center. Standard residential spacing is 16 or 24 inches.
Trim and roof edge terms
These describe the visible edges and details where the roof meets the rest of the house.
- Eave — the lower horizontal edge of the roof, where it overhangs the wall. The "drip line" of the roof.
- Rake — the sloped edge of the roof at the gable end, running from eave to ridge.
- Soffit — the underside of the eave or rake overhang, typically finished with vented panels for attic ventilation.
- Fascia — the vertical board mounted at the eave end of the rafters, behind which the gutter typically attaches.
- Frieze board — a horizontal trim board between the top of the wall and the soffit. Largely cosmetic.
- Bargeboard (or vergeboard) — the trim board running along the rake edge of a gable. Decorative on traditional architectural styles.
- Cornice — the broader assembly of fascia, soffit, frieze, and any decorative moldings at the eave. The architectural detail of the roof edge.
- Crown molding — decorative top moulding, sometimes used at the cornice in traditional architectural styles.
- Overhang — the horizontal distance the roof extends past the wall, measured perpendicular to the wall. Typical residential: 12-24 inches.
- Header — a structural beam over a window or door opening. Sized per IRC R602.7 prescriptive tables or by an engineer.
- Rake board — a board running along the rake edge under the rake fascia, typically just visible from the gable end.
Water management terms
Roofs exist primarily to keep water out of the building. These terms describe the components and details that handle water flow.
- Valley — the inside corner where two sloped roof planes meet. Water from both planes flows down the valley to the eave.
- Hip — the outside corner where two sloped roof planes meet. Water flows away from the hip on each plane.
- Ridge — the peak where two opposing roof planes meet at the top.
- Step flashing — small L-shaped pieces of metal flashing installed in courses where a roof meets a vertical wall. Each piece overlaps the one below.
- Counter flashing — a piece of flashing installed against a vertical wall (typically masonry) that overlaps and protects the step flashing below it.
- Apron flashing — a single horizontal flashing strip installed where a roof slope meets a vertical wall at the bottom of the slope (like below a chimney).
- Cricket (or saddle) — a small triangular roof structure built behind a chimney or other obstruction to divert water around it.
- Kickout flashing — a piece of flashing installed at the bottom of a roof-wall intersection to redirect water away from the wall siding.
- Drip edge — a metal flashing strip installed along eaves and rakes to direct water past the fascia.
- Gutter — a horizontal trough along the eave that collects rainwater and routes it to downspouts.
- Downspout (or leader) — a vertical pipe that carries water from the gutter down to the ground or drainage system.
- Splash block — a small concrete or plastic block at the base of a downspout that disperses water away from the foundation.
- Gutter guard — a screen or cover over a gutter that keeps debris out while allowing water to enter.
- Scupper — an opening through a parapet wall or curb that allows water to drain off a flat roof to the exterior.
Ventilation terms
Attic ventilation prevents heat and moisture buildup that shortens roof life. These terms describe the components.
- Soffit vent — a vent in the underside of the eave that lets fresh air enter the attic. Intake side of the ventilation system.
- Continuous soffit vent — a long perforated strip that runs the full length of the eave. Provides more vent area than discrete vents.
- Ridge vent — a vent that runs along the peak of the roof, allowing hot air to exit. Exhaust side of the ventilation system.
- Gable vent — a vent in the gable wall (rather than the roof). Less effective than ridge ventilation for most attic geometries.
- Off-ridge vent (or roof vent) — a discrete vent installed near but not at the ridge. Used when ridge ventilation is impractical.
- Turbine vent (or whirlybird) — a wind-powered rotating exhaust vent. Less common in modern construction.
- Powered attic ventilator — an electric exhaust fan in the attic. Controversial — can pull conditioned air from the living space if intake is undersized.
- Net free vent area (NFVA) — the open area of a vent through which air can pass, measured in square inches. Code requires 1 sq ft of NFVA per 150 sq ft of attic floor area, balanced 50/50 between intake and exhaust.
- Balanced ventilation — equal NFVA between intake (soffit) and exhaust (ridge), required by code for proper air movement.
- Air baffle — a foam or cardboard channel installed in the rafter bay above the wall to keep insulation out of the soffit-to-attic airway.
Fasteners and hardware
These are the small metal components that hold a roof together.
- Roofing nail — a galvanized steel nail with a large flat head, typically 1.25 to 2 inches long. Used to fasten shingles to the deck.
- Coil nail — a roofing nail formatted for use in a pneumatic coil nailer. Standard for production roofing.
- Cap nail — a nail with a plastic cap that distributes load and seals the underlayment around it. Used to fasten synthetic underlayment.
- Hurricane tie (or rafter tie) — a metal connector that secures the rafter to the wall plate, resisting wind uplift. Required by code in hurricane zones.
- Joist hanger — a metal U-shaped bracket that supports the end of a joist or rafter where it bears on a beam.
- H-clip — a small metal clip that supports the unsupported edge of roof sheathing between rafters. Spaced 24 inches OC on most decks.
- Truss plate (or gang nail) — a perforated metal plate pressed into the joints of a wood truss to connect the members.
- Strap (or hold-down) — a metal strap connecting framing members across joints, providing tension capacity.
- Lag screw — a heavy-duty wood screw with a square or hex head, used to fasten beams and structural members.
Code and inspection terms
Roofing work in the U.S. is governed by building codes and inspected by local authorities. These terms come up in that context.
- IRC — International Residential Code. The model code for one- and two-family dwellings, adopted in some form by most U.S. jurisdictions.
- IBC — International Building Code. The model code for commercial and larger residential buildings.
- AHJ — Authority Having Jurisdiction. The local building department or other entity that issues permits and conducts inspections.
- Permit — written authorization from the AHJ to perform construction work. Required for most roofing projects beyond minor repairs.
- Inspection — a code official's in-person review of work at specific stages (typically during tear-off, after underlayment, and at completion).
- CO (Certificate of Occupancy) — final approval that a structure is safe to occupy. Required after major renovations or new construction.
- Setback — the minimum distance a structure must be from a property line, road, or other reference. Affects where eaves can extend.
- Snow load — the design weight of snow accumulated on a roof, in pounds per square foot. Varies by location; check your AHJ for ground snow load values.
- Wind load — the design pressure from wind on a structure. Hurricane-prone regions have higher wind load requirements.
- Live load — the design weight from temporary loads like people, snow, and equipment. Code-minimum residential roof live load is 20 psf.
- Dead load — the design weight from permanent loads — the weight of the roof structure and finishes themselves.
Tools and equipment terms
These describe the tools used in roofing work.
- Speed square — a triangular framing square used for marking 90° and angled cuts on dimension lumber. Has a built-in protractor for any angle up to 90°.
- Framing square — a large L-shaped steel square with rafter and stair tables embossed on the blade. Used for traditional rafter step-off layout.
- Combination square — a sliding-blade square for fine layout, marking parallel lines, transferring depths, and checking 45°.
- Roof bracket (or roof jack) — a metal bracket that hooks under shingles and supports a plank, providing a foothold on steep roofs.
- Pump jack — an adjustable scaffold system that climbs a vertical pole, used for siding and roofing work on tall walls.
- Slate hook (or slate hammer) — a specialized tool for cutting and installing slate roofing.
- Shingle hammer (or roofing hatchet) — a hammer with a built-in gauge for setting shingle exposure during hand-nail installations.
- Tin snip — a metal-cutting hand shear used for trimming flashing, drip edge, and other thin-gauge metal.
- Brake (or sheet metal brake) — a portable bench tool that bends sheet metal to precise angles. Used for fabricating custom flashing.
- Coil nailer — a pneumatic nail gun that uses coils of roofing nails. Standard tool for production roofing crews.
Damage and repair terms
These describe the failures roofers diagnose and the work they do to fix them.
- Granule loss — gradual wearing away of the protective granules on asphalt shingles. Heavy granule loss in gutters indicates end-of-life.
- Curling — shingle edges lifting up from the substrate as the shingle ages and dries. Indicates near end-of-life.
- Cupping — shingle middles dipping down between curled edges. Same root cause as curling.
- Blistering — small bubbles in the shingle surface caused by trapped moisture or manufacturing defects.
- Streaking (or staining) — dark streaks on shingles caused by algae growth (Gloeocapsa magma). Cosmetic; treatable with zinc strips.
- Hail damage — circular bruises or punctures in shingles from hail impact. Insurance-covered if recent.
- Wind damage — shingles lifted, creased, or torn off by wind. Insurance-covered if from a documented storm.
- Ice dam — accumulated ice at the eave that traps melting snow behind it, forcing water under the shingles.
- Leak — water entering the structure through the roof. Diagnosis requires tracing from the visible water mark back to the actual entry point.
- Flashing failure — degradation or displacement of flashing causing leaks at chimneys, skylights, walls, or valleys. Most common leak source.
Need to run the numbers?Use the free roof pitch calculator on the home page to convert pitch to angle, calculate rafter length, or estimate roof area in any unit.