Roofing Terminology S-U

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SADDLE- A ridge in the roof deck, whose top divides two sloping parts of the roof so that water will be diverted to the roof drains.

SATURATED FELT- Felt that has been saturated with bitumen.

SAW TOOTH ROOF- Where reviewed from the end, such a roof serrated or tooth profile similar to the teeth of a saw.

SCRIM- A woven or mat-type fabric that is used as a membrane sandwich between other material to provide reinforcement and stretch resistance.

SCUPPER- An outlet in the wall of a building or a parapet wall for drainage of water from a flat roof.

SEALANT- Generic term for a multitude of materials used to seal joints or junctures against moisture or weather.

SELF-HEALING- A term used in reference to a material which melts with the heat from the sun's rays, and seals over cracks that were earlier formed from other causes.

SELF-LEVELING- A viscous material that is applied by pouring. In its uncured state, it spreads out evenly.

SELVAGE- The unsurfaced strip along a sheet of roll roofing which forms the under portion at the lap in the application of the roof covering.

SHED ROOF- A roof having only one slope or pitch, with only one set of rafters which fall from a higher to a lower wall.

SHEATHING- The boards of sheet type material, plywood or asphalt saturated sheets, nailed to studding or roofing rafters as the base for application of the roof covering.

SHINGLE-FASHION- The pattern formed by laying parallel felt rolls with lapped joints so that one longitudinal edge overlaps the longitudinal edge on the adjacent felts. Shingle fashion application begin at the low point on a roof so that one ply drains water to a lower one and so on to a drain or to the roof edge.

SHINGLES- Small units of material which are laid in a series of overlapping rows as a roof covering on pitched roofs.

SHINGLE WARRANTY- Shingle warranties are often confused with "system warranties."  Shingle warranties are prorated, and usually carry a very small value after the first 5 years of shingle life.  In other words, the warranty that comes with shingles is designed to never be redeemed for new shingles or labor.

SIGN ANCHOR- A component usually formed with steel angles which penetrates the BUR and is fastened to the deck.

SINGLE PLY- A descriptive term signifying a roof membrane composed of only one layer of material such as EPDM, TPO or PVC.

SINGLE TEE- The name given to a type of precast concrete deck which has one stiffening rib integrally cast into slab.

SITE- The physical grouping of a number of roofs or buildings at a geographical location.

SKY DOME- A type of skylite exhibiting a characteristic translucent plastic domed top.

SKYLIGHT- A structure on a roof that is designed to admit light and is somewhat above the plane of the roof surface.

SLAG- A by-product of smelting ore such as iron, lead or copper.

SLATE- A dark gray stratified stone cut relatively thin and installed on pitched roofs in a shingle like fashion.

SLIPPAGE- It is the sliding, lateral movement between adjacent to plies of felt along the plane of the bitumen film separating them, which results in a randomly wrinkled appearance.

SLOPE- Incline or pitch of roof surface.

SOFFIT- The underside of a part or member of a building extending out from the plane of the building walls.

SOFTENING POINT- The temperature at which a substance changes from a hard material to a softer and more viscous material.

SMOOTH SURFACE TEXTURE- In SPF roofing, a relatively smooth surfaced texture that is considered ideal for receiving the base coating.

SMOOTH-SURFACED ROOF- A roof with no surfacing or with a smooth surfacing such as emulsion and/or a reflective coating.

SNOW GUARD- Devices secured to the roof to prevent snow and ice from sliding off of a roof.

SNOW LOAD- A roof load resulting from snowfall. Snow load is a major structural consideration when roofs are designed in areas that receive heavy snow.

SOFFIT- The underside of a roof overhang.

SOFFIT VENT- An intake ventilation device located in the soffit. An exhaust vent should be installed on or near the ridge of the roof to work in conjunction with the soffit vent in order to properly ventilate the attic space. The ratio of intake vent area to exhaust vent area should be 1-1.

SOFTENING POINT- The temperature at which bitumen will begin to flow.

SOFTENING POINT DRIFT- A change in the softening point of bitumen.

SOIL STACK- A pipe that penetrates a roof and is used to vent a building's plumbing.

SOLID MOPPING- To continuously apply hot asphalt or coal tar leaving no areas without bitumen.

SOLVENT- A liquid that is part of a substance and is used to make that substance easier to work with. Once applied, the solvent evaporates and leaves the working characteristics of the substance. Examples are solvent-based adhesives and solvent-based mastics.

SOLVENT WELD- To weld materials using a liquid solvent.

SPALLING- The chipping or flaking of concrete, bricks, or other masonry where improper drainage or venting and freeze/thaw cycling exists.

SPAN- The horizontal distance between supporting structures such as beams, trusses or columns.

SPECIFICATION- Detailed written instructions which, when clear and concise, explain each phase of work to be done.

SPLITTING- The formation of long cracks completely through a roof membrane. Splits are frequently associated with lack of allowance for expansion stresses. They can also be a result of deck deflection or change in deck direction.

SPRAYED POLYURETHANE FOAM (SPF)- A monolithic sprayed-on roofing material with a high R-value; formed when isocyanate ("A" component) and resin ("B" component) are mixed at a 1-1 ratio.

SPRI- Single Ply Roofing Institute

SQUARE- A term used by the roof industry to indicate an amount of roof area equal to 100 square feet.

SPUD- The removal of gravel or heavy accumulations of bitumen from roof membranes by means of chipping or scraping

STACK- A vertical pipe projecting through a BUR that carries off smoke or gases.

STACK EFFECT- The occurrence where air escapes through opening in the upper part of a building and is replaced with outside air that enters through an opening lower down. In roofing, the Stack Effect helps create proper airflow for attic or roof space ventilation. The Stack Effect will be affected by atmospheric conditions such as temperature and wind.

STANDING SEAM- A type of joint often used on metal roofs.

STARTER STRIPS- In the construction of the BUR the narrow strips of roofing felts, cut from standard width rolls, that are applied at the beginning point so as to assure uniform configuration of the specified number of plies.

STATIC LOAD- In roofing the total amount of permanent non moving weight that is applied to given surface areas.

STEEP SLOPE ROOFING- Generally all slopes higher than 4/12 are considered steep slopes.

STEP-FLASHING- Metal flashing pieces installed at side-walls and chimneys for weather-proofing.

STYRENE- A colorless oily liquid, C6H5CH-CH2, the monomer for polystyrene.

STYRENE BUTADIENE STYRENE (SBS)- The modifying agent used in SBS modified asphalt roofing materials that gives the material a rubber like quality. SUBSTRATE A part or substance which lies below and supports another.

SUMP- A reservoir sometimes forming part of a roof drain. A depression in the roof deck of a building at a roof and delivery it to the drain.

SURFACE EROSION- The effect on a surface after being worn away from abrasion or weathering.

SURFACE TEXTURE- The final appearance and quality of an SPF surface. SPF surface textures will be one of the following- Orange Peel Surface Texture, Coarse Orange Peel Surface Texture, Smooth Surface Texture, Verge of Popcorn Surface Texture, Popcorn Surface Texture, and Tree-Bark Surfaced Texture.

SYSTEM WARRANTY- (see "Shingle Warranty") A warranty that comes with an entire roofing system installation.  For instance, some shingle manufacturers offer very strong, long-term system warranties if the laborers are manufacturer-trained and if all portions of installation adhere directly to manufacturer's specifications.  This system warranty has massive value in relation to the standard shingle warranty.

SURFACING- The top-most layer of the roof system designed to protect the system from damage.

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TAB- The portion of an asphalt shingle that is outlined by the cutouts.

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.

TAR BOIL- A small bubble found in the flood coat of an aggregate-surfaced built-up roof; usually the result of trapped moisture vapor.

TEAR OFF- A term used to describe the complete removal of the  roof membrane and insulation down to and exposing the roof deck.

TELEGRAPHING- When shingles reflect the uneven surface beneath them. Shingles installed over buckled shingles may show some buckles.

TENSILE STRENGTH- The amount of longitudinal pulling stress that a material can withstand before being pulled apart.

TERMINATION- The sealed edges of a roof membrane.

TERMINATION BAR- A bar, usually metal or vinyl, used to seal and anchor the free edges of a roof membrane.

THATCH ROOF- A roof covering made with straw, palms, reeds or other natural growths that are bound together in order to shed water.

THERMAL RESISTANCE (R)- The measure of a material's ability to resist heat flow. The formula for Thermal Resistance is R = L / k where (L) is the material's thickness and (k) is the material's Thermal Conductivity constant. The higher a material's R-value, the better it insulates, and conversely. For more information, click here.

THERMAL MOVEMENT- The measured amount of dimensional change, a material exhibits as it is warmed or cooled.

THERMAL SHOCK- The stress built up by sudden and appreciable changes in temperature.

THERMAL STRESS- Stress to a roof system or component caused by expansion and / or contraction from temperature change.

THERMOPLASTIC MATERIAL- Solid material which is softened by increasing temperatures and hardened by decreasing temperatures.

TIE-IN- A term used to describe the joining of a new roof with the old.

TIE-OFF- A watertight seal used to terminate roof membranes at system adjuncts, terminations, flashings, or substrates. Can be temporary (see Night Seal) or permanent.

TILT-UP WALL- Cast concrete units which are preformed which, when cured, are tilted to their vertical position and secured by mechanical fasteners to prior erected structural steel. May be pre-cast.

TOP MOPPING- The finished mopping of hot bitumen on a built-up roof.

TORCHING- Applying direct flame to a membrane for the purpose of melting, heating or adhering.

TREEBARK SURFACE TEXTURE- An SPF surface deemed unacceptable for coating. This surface texture has deep valleys and is similar in appearance to rough tree bark.

TRUSS- A major supporting structure usually timber for roof decks.

TUCK POINTING- The re-grouting of defective mortar joints in a masonry or brick wall.

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ULTRAVIOLET LIGHT (UV)- A form of luminous energy occupying a position in the spectrum of sunlight beyond the violet, and having wavelengths that do not enter the visible spectrum. UV rays accelerate deterioration of roof materials.

UNDER-DRIVEN- Term used to describe a fastener not fully driven flush to the shingles surface.

UNDERLAYMENT- A material installed over the roof deck prior to the application of the primary roof covering. Usually consists of fifteen (15#) or thirty (30#) pound organic felt but can also be self-adhering such as an ice and water protection membrane.

UNDERWRITERS LABORATORIES (UL)- A non-profit agency which functions as the testing arm of the National Board of Fire Underwriters. It maintains laboratories for the examination and testing of various devices, systems, and materials to determine their safety against the hazards of fire, wind, and accidents.