Fascia: Vertical roof trim located along the perimeter of a building, usually below the roof level. Its use can be either decorative or for waterproofing.
Fasteners: Devices used to secure roof system components.
Feathering Strips: Strips of wood that are placed along the butt ends of wood shingles to form a somewhat smooth surface so that the shingles can be roofed over without removal.
Felt: A roofing sheet made of interwoven fibers. The fibers can be wood or vegetable for Organic Felts, glass fibers for fiberglass felts, polyester, or asbestos.
Felt Machine: A machine that will install bitumen and felt at the same time.
Ferrule: A metal sleeve used as a spacer to keep gutter from being beat up when secured to fascia with spikes.
Fiberglass Insulation: Insulation composed of glass fibers used to insulate walls and roofs. It can be rigid board or blanket insulation.
Field of the Roof: Refers to the central part of a roof away from the perimeter.
Field Seam: A non-factory material seam made by joining overlapping seams together with adhesives, heat welders, or other means.
Filler: An inert ingredient added to roofing materials in order to alter their physical characteristics.
Fillet: A sealant material installed at horizontal and vertical planes to remove 90° angles.
Film: A membrane or sheeting material with a nominal thickness of 10 mils or less.
Fin: A sharp protrusion in a roof deck that can damage roof components.
Fine Mineral-Surfacing: A fine mineral material on the surface of roofing materials to prevent them from sticking to surfaces. 50% of this material has to pass through a sieve with holes that are 1/35" in size (#35 sieve).
Fishmouth: An opening along the exposed edge of an installed ply of felt caused by shifting the ply during installation. Repair these by making a slice along their entire length and feathering two plies of felt over the fishmouth for a minimum coverage of one foot all the way around.
Flaking: Occurs when a coating loses its cohesion.
Flame Retardant: A substance used to impede a materials tendency to burn or ignite.
Flame Spread: Per ASTM E 84, a measure of relative combustibility. The flame spread of a tested material is rated relative to asbestos cement board (flame spread = 0) and red oak flooring (flame spread = 100).
Flammability: The ability of a material to burn or ignite.
Flange: A projection edge of a roof component such as flashings, skylight frames, pre-manufactured curbs, etc. Usually refers to the part that sits on the roof surface.
Flash: v. To install flashing components.
Flash Point: The lowest temperature of a liquid material at which combustion will occur when air reaches its surface.
Flashing: Components used to seal the roof system at areas where the roof covering is interrupted or terminated. For example, pipes, curbs, walls, etc. all have special components that, when correctly installed, will help prevent moisture entry into the roof system or building.
Flashing Cement: A trowelable mixture of solvent-based bitumen and mineral stabilizers. Flashing cement that may contain asbestos stabilizers is categorized by ASTM standard D 2822-91 (1997) or for non-asbestos, ASTM standard D 4586-93. Flashing Cement is the term for Asphalt Roof Cement that can be used on vertical surfaces and has a high softening point, low ductility and conforms to the requirement of ASTM Specification D 312, Types II or III; or Specification D 449, Type III. See also Asphalt Roof Cement and Plastic Cement.
Flashing Collar: A flashing component used to seal soil pipe vents, hot stacks or other roof penetrations.
Flat Lock: A type of interlocking two separate metal panels by folding one panel over on top itself and the folding the other down under itself and then hooking the panels together.
Fleece: Mats or felts used as a membrane backer and composed of fibers.
Flood Coat: The surfacing layer of bitumen into which aggregate is embedded on an aggregate-surfaced built-up roof. A flood coat is applied at an approximate rate of 45 to 60 pounds per square (100 square feet).
Flood Test: A water test performed to determine the effectiveness of a roof covering.
Flow: To become fluid in character.
Fluid-Applied Elastomer: A liquid elastomeric material that cures to form a continuous waterproofing membrane.
FM: Short for Factory Mutual Research Corporation.
Foam Stop: The edge metal used to terminate Sprayed Polyurethane Foam.
Framed Opening: an structurally-framed opening in a roof of a building for use in installing large items such as HVAC units, skylights, or ventilators.
Froth Pack: A term used to describe small, disposable aerosol cans of SPF.