ALGAE DISCOLORATION

A type of roof discoloration caused by algae. Commonly called fungus growth.

ASPHALT

A bituminous waterproofing agent applied to roofing materials during manufacture.

BACKER

Narrow slates laid roughly over a wide slate to accommodate the increasing number of slates as work progresses up the roof.

BASE FLASHING

Portion of the flashing attached to or resting on the deck to direct the flow of water onto the roof covering.

CAULK

To fill a joint with mastic or asphalt cement to prevent leaks.

CHALK LINE

A line made on the roof by snapping a taut cord dusted with chalk.

DECK

A surface installed over the supporting framing members, to which the roofing is applied.

DORMER

A framed window unit projecting through the sloping plane of a roof.

EAVES

The horizontal, lower edge of a sloped roof.

EXPOSURE

Portion of the roofing exposed to the weather after installation.

FELT

Fibrous material soaked with asphalt and used as an underlay to sheathing paper.

FIXINGS

Nails or pegs.

FLASHING

Pieces of metal or roll roofing used to prevent seepage of water into a building.

GABLE

The upper portion of a sidewall that comes to a triangular point at the ridge of a sloping roof.

GAUGE

The spacing of laths or battens up the roof slope.

GRP

Glass Reinforced Polyester.

GUTTER

The trough that channels water from the eaves to the downspouts.

HEAD

The top edge of a laid stone slate.

INSULATION

Any of a variety of materials designed to reduce the flow of heat, either from or into a building.

JOIST

Any of the small timbers, metal or wood beams arranged parallel from wall to wall to support a floor, ceiling, or roof of a building.

KNEE CAP

A metal cover trim that fits over a panel rib after it has been cut and bent.

LAP

Covering the surface of one shingle or roll with another.

LATH

Split wooden support for hanging stone slates.

LEAD

A soft workable metal used for miscellaneous flashings.

MASTIC

An asphalt based cement used to bond roofing materials.

MEMBRANE

A flexible or semi-flexible material, which functions as the waterproofing component in a roofing or waterproofing assembly.

NEOPRENE

A synthetic rubber (polychloroprene) used in liquid-applied and sheet-applied elastomeric roof membranes or flashings.

OVERHANG

Portion of the roof structure that extends beyond the exterior walls of a building.

PITCH

The angle of the rafters to the horizontal... the degree of roof incline expressed as the ratio of the rise to the span in feet.

POINTING

Use of mortar to fill the vertical joints and to seal the tail gap of stone slating.

QUALITY ASSURANCE

Statement of warranty; guarantee of workmanship.

RAFTER

The supporting framing member immediately beneath the deck, sloping from the ridge to the wall plate.

REROOFING

The process of re-covering, or tearing-off and replacing an existing roof system.

RIDGE

Highest angle on the roof, represented by a horizontal line where two roof areas intersect, running the length of the plane.

SLATE

Natural flat, retangular roofing material, sometimes referred to as flags or flagstones.

SOFFIT

The finished underside of the eaves.

SPLITTING

A rupture or tear in a material or membrane resulting from tensile forces.

TAR

A brown or black bituminous material, liquid or semi-solid in consistency, in which the predominating constituents are bitumens obtained as condensates in the processing of coal, petroleum, oil-shale, wood, or other organic materials.

UNDERLAYMENT

An asphalt-saturated felt or other sheet material installed between the roof deck and the roof system, usually used in a steep-slope roof construction. Underlayment is primarily used to separate the roof covering from the roof deck, to shed water, and to provide secondary weather protection for the roof area of the building.

VALLEY

The internal angle formed by the intersection of two sloping roof planes.

VENT

An outlet for air that protrudes through the roof deck such as a pipe or stack. A device installed on theroof, gable or soffit ventilating the underside of the roof deck.

WATERPROOF

The quality of a membrane, membrane material, or other component to prevent water entry.

WEATHERED

The process by which stone is broken down and 'weathered'.

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No inclusion here for X – please e-mail if you know of some appropriate acronyms or terms.

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No inclusion here for Y – please e-mail if you know of some appropriate acronyms or terms.

ZINC

A metal that has application considerations including high expansion-contraction rates and low-temperature restrictions.