Glossary of Roofing and Waterproofing Terms

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Saddle: a relatively small raised substrate or structure constructed to channel or direct surface water to drains or off the roof. A saddle may be located between drains or in a valley, and is often constructed like a small hip roof or like a pyramid with a diamond-shaped base. (See Cricket.)

Sag: undesirable excessive flow in material after application to a surface.

Saturated Felt: a felt that has been partially saturated with low softening point bitumen.

SBCCI: Southern Building Code Congress International, Inc.

SBS: see Styrene Butadiene Styrene.

Scarfed: shaped by grinding.

Screeding: the process of striking off excess concrete to bring the top surface of the concrete to the proper finish and elevation.

Screen Wall: a nonstructural wall erected around units or curbs on a roof. Typically the framing consists of girts with a wood or metal covering attached to the frame.

Scrim: a woven, nonwoven, or knitted fabric, composed of continuous strands of material used for reinforcing or strengthening membranes. Scrim may be incorporated into a membrane by the laminating or coating process.

Scuttle: a hatch that provides access to the roof from the interior of the building.

SDI: Steel Deck Institute

Seal: (1) a generic term for a function that prevents or controls the passage of water; (2) to secure a roof or structure from the entry of moisture.

Sealant: a single- or multi-component polymeric or bituminous-based material used to weatherproof many types of construction joints where moderate movement is expected. The material comes in various grades: pourable, self-leveling, non-sag, gun grade, and cured or uncured tapes.

Sealer: a coating designed to prevent absorption of finish coats into porous surfaces; a coating designed to prevent bleeding.

Sealing Washer: a rubber or neoprene washer, sometimes metal-backed, typically assembled on a fastener to prevent water from migrating into and through the fastener hole.

Seam: a joint formed by mating two separate sections of material. Seams may be made or sealed in a variety of ways, including adhesive bonding, hot-air welding, solvent welding, using adhesive tape, sealant, etc.

Seam Strength: the force or stress required to separate or rupture a seam in the membrane material.

Self-Adhering Membrane: a membrane that can adhere to a substrate and to itself at overlaps without the use of an additional adhesive. The undersurface of a self-adhering membrane is protected by a release paper or film, which prevents the membrane from bonding to itself during shipping and handling.

Self-Drilling Screw: a fastener that drills and taps its own hole during application.

Self-Sealing Shingle: an asphalt shingle containing factory-applied strip or spots of heat sensitive adhesive intended to adhere the overlying shingle once installed on the roof and warmed by the sun.

Self-Tapping Screw: a fastener that forms receiving threads when turned into a previously drilled hole.

Self-Vulcanized Membrane: a membrane manufactured from compounds that are thermoplastic during manufacture and installation, but whose polymers eventually cross-link and cure during exposure.

Selvage: (1) an edge or edging that differs from the main part of a fabric, granule-surfaced roll roofing or cap sheet, or other material; (2) a specially defined edge of the material (lined for demarcation), which is designed for some special purpose, such as overlapping or seaming.

Selvage Edge: an edge designed for certain sheet good materials, e.g., mineral-surfaced sheets. With mineral surfaced sheets, the surfacing is omitted over a portion of the longitudinal edge of the sheet (e.g., mineral surface cap sheet) in order to obtain better adhesion of the overlapping sheet.

Service Temperature Limits: the minimum or maximum temperature at which a coating, SPF, or other material will perform satisfactorily.

Set: to convert into a fixed or hardened state by chemical or physical action.

Shading: slight differences in surfacing color, such as shingle granule coloring, that may occur as a result of manufacturing operations.

Shark Fin: an upward-curled felt side lap or end lap.

Shear Strength: (in roofing) the stress required to disrupt a seam or bonded joint or attachment by forcing the substrate material to slide out from the overlying material or vice versa.

Shed Roof: a roof containing only one sloping plane. Has no hips, ridges, or valleys. (See Figure 22.)

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Sheet Metal Flashing: see Metal Flashing.

Shelf Life: the period of time within which a material such as coating or SPF components remain suitable for use.

Shingle: (1) individual unit of prepared roofing material designed for installation with similar units in overlapping rows or courses on inclines normally exceeding 3:12 slope (25%); (2) to cover with shingles; (3) to apply any roofing material in succeeding overlapping rows or courses similar to shingles.

Shingling: (1) the application of shingles; (2) the procedure of applying shingles or laying parallel felts so that one longitudinal edge of each felt overlaps and the other longitudinal edge of the adjacent shingle or felts underlaps. Felts are normally shingled from a downslope portion of the roof to the upslope portion of the roof area so that runoff water flows over rather than against each felt lap. Felts are also applied in shingle fashion on relatively low slopes.

Shore "A" Hardness: a measure of firmness of a material by means of a Durometer Hardness Gauge. (A measure of 20 is about the firmness of a gum eraser; 90 is about that of a rubber heel.)

Shrinkage: a reduction in size.

Shrinkage Crack: in waterproofing, a separation in a material, like a concrete substrate, caused by the inability of the material to resist a reduction in size which occurs during its hardening process, curing process, or both.

Sl: the international symbol for the metric unit (Le Systeme International d'Unites).

Side Lap: the continuous longitudinal overlap of neighboring like materials. (See Figures 23 and 24.)

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Side Lap Fastener: a fastener used to connect adjacent panels together at the side lap.

Side Lap-Ganging: pattern or application for roofing materials, as related to the amount of cover or side overlap of adjacent like materials.

Siding: the exterior wall finish material applied to a light frame wood structure.

Sieve: an apparatus with uniform sized openings for separating sizes of material.

Silicone-based Water Repellants: any of the organopolysiloxanes (silicone derivative) applied to masonry materials for dampproofing or repelling water.

Sill: the bottom horizontal framing member of an opening, such as below a window or door.

Sill Flashing: a flashing of the bottom horizontal framing member of an opening, such as below a window or door.

Single Coverage: roofing material that provides one layer over the substrate to which it is applied.

Single-Lock Standing Seam: a standing seam that utilizes one overlapping interlock between two seam panels, in contrast with the double interlocking used in a double standing seam.

Single-Ply Membranes: roofing membranes that are field applied using just one layer of membrane material (either homogeneous or composite) rather than multiple layers.

Single-Ply Roofing: a roofing system in which the principal roof covering is a single layer flexible membrane, often of thermoses, thermoplastic, or polymer modified bituminous compounds.

Single-Ply System: generally, there are six types of single-ply roofing systems:

1) Fully-adhered

2) Loose-laid

3) Mechanically-fastened

4) Partially-adhered

5) Protected membrane roof

6) Self-adhering

Skinning: the formation of a dense film on the surface of a liquid coating or mastic.

Skylight: a roof accessory, set over an opening in the roof, designed to admit light. Normally transparent, and mounted on a raised framed curb.

Slab-On-Grade: a horizontal placement of concrete placed directly over a prepared earth substrate.

Slag: a hard, air-cooled aggregate that is left as a residue from blast furnaces, which may be used as a surfacing material on certain (typically bituminous) roof membrane systems.

Slate: a hard, brittle metamorphic rock consisting mainly of clay minerals, used extensively as dimensional stone for steep roofing, and in granular form as surfacing on some other roofing materials.

Slating Hook: a steep-slope roofing attachment device, shaped like a hook, that can be used for fastening roofing slate.

Slip Sheet: sheet material, such as reinforced kraft paper, rosin-sized paper, polyester scrim, or polyethylene sheeting, placed between two components of a roof assembly (such as between membrane and insulation or deck) to ensure that no adhesion occurs between them, and to prevent possible damage from chemical incompatibility, wearing, or abrasion of the membrane.

Slit Sample: a small cut about 1 " x A" x 4/~", in a half-moon shape, used to measure coating film thickness.

Slope: the angle of incline, usually expressed as a ratio of rise to run, or as a percent. (See Roof Slope.)

SMACNA: Sheet Metal and Air Conditioning Contractors National Association

Smooth Surface Texture: the surface shows spray undulation and is ideal for receiving a protective coating. Even though the surface texture is classified as smooth, the theoretical coverage rate cannot be used without adding a minimum of 5% additional material to adequately cover the undulation.

Smooth Surfaced Roof: a roof membrane without mineral granule or aggregate surfacing.

Snap-On Cap: a separate cap that snaps on over the vertical legs of some single standing or batten seam metal roof systems.

Snow Guard: a series of devices attached to the roof in a pattern that attempts to hold snow in place, thus preventing sudden snow or ice slides from the roof.

Snow Load: a load imposed on buildings or other structures due to snowfall. (Categorized as live or environmental load.)

Soffit: the enclosed underside of any exterior overhanging section of a roof cave.

Soffit Vent: a premanufactured or custom built air inlet source located at the downslope eave or in the soffit of a roof assembly.

Softening Point: the temperature at which bitumen becomes soft enough to flow, as determined by a closely defined method (ASTM Standard test method D 36 or D 3461).

Softening Point Drift: a change in the softening point of bitumen. (See Fallback.)

Soil Stack: a sanitation pipe that penetrates the roof; used to vent plumbing fixtures.

Solder: a lead/tin mixture that is melted and used to bond two pieces of some metals together.

Solid Mopping: see Mopping.

Solids Content: the percentage of non-volatile matter in a coating or mastic formulation; may be expressed as a volume or weight percent.

Solvent: liquid used to dissolve or disperse film-forming constituents, and which evaporates during drying and does not become a part of the dried film.

Solvent Cleaners: used to clean some single-ply roofing membranes prior to splicing, typically including heptane, hexane, white gasoline, and unleaded gasoline.

Solvent Welding: a process where a liquid solvent is used to chemically weld or join together two or more layers of certain membrane materials (usually thermoplastic).

Spalling: a condition in which the outer layer or layers of masonry or concrete material begin to break off or flake away.

Special Steep Asphalt: Type IV Asphalt. (See Asphalt.)

Specification: a statement of requirements for a given job or project. Usually describes products, materials, and processes to be used. A specification may also contain terms of the contract.

SPF: sprayed polyurethane foam.

SPF Compound: a term used to describe the raw materials (isocyanate and resin) used to make polyurethane foam.

SPI: The Society of the Plastics Industry

SPI/SPFD: The Society of the Plastics Industry/Sprayed Polyurethane Foam Division

Splash Block: a small masonry or polymeric block laid on the ground or lower roof below the opening of a downspout used to help prevent soil erosion and aggregate scour in front of the downspout.

Splice: bonding or joining of overlapping materials. (See Seam.)

Splice Plate: a metal plate placed underneath the joint between two pieces of metal.

Splice-Tape: cured or uncured synthetic rubber tape used for splicing membrane materials.

Split: a rupture (generally linear) or tear in a material or membrane resulting from tensile forces.

Split Sheet: see Nineteen-lnch Selvage.

Split Slab: a term used to describe two separate concrete slabs. The first is placed as a slab-on-grade or suspended slab, and covered with waterproofing and a drainage system. The second slab, also referred to as a topping slab, is then placed over the underlying slab and waterproofing.

Spot Mopping: see Mopping.

Sprayed Polyurethane Foam (SPF): a foamed plastic material, formed by spraying two components, PMDI ([A] component) and a resin ([B] component) to form a rigid, fully adhered, water-resistant, and insulating membrane.

Spread Coating: a manufacturing process in which membranes are formed using a liquid compound, prepared in mixers and then fed to individual coalers. The mixture is spread onto a supporting reinforcement base layer. After coating, the material passes through a channel causing it to change from a paste to a solid membrane, in sheet form.

SPRI: Single Ply Roofing Institute

Sprinkle Mopping: see Mopping.

Spunbond: a type of nonwoven fabric formed from continuous fiber filaments that are laid down and bonded continuously, without an intermediate step.

Spunlaced: a nonwoven fabric made by mechanically bonding a dry-laid staple fabric by water jet, which entangles the individual fibers.

Square: 100 square feet (9.29 m2) of roof area.

Square-Tab Shingles: shingles with tabs that are all the same size and exposure.

Stainless Steel: an alloy of steel that contains a high percentage of chromium. Also may contain nickel or copper. Generally, has very good resistance to corrosion.

Standing Seam: a metal roof system that consists of an overlapping or interlocking seam that occurs at an upturned rib. The standing seam may be made by turning up the edges of two adjacent metal panels and overlapping them, then folding or interlocking them in a variety of ways.

Starter Course: the first layer of roofing, applied along a line adjacent to the downslope perimeter of the roof area. With steep-slope watershedding roof coverings, the starter course is covered by the first course.

Starter Sheets: (1) felt, ply sheet, or membrane strips that are made or cut to widths narrower than the standard width of the roll, used to start the shingling pattern at an edge of the roof; (2) particular width sheets designed for perimeters in some mechanically attached and fully adhered single-ply systems.

Starter Strip: roll roofing or shingle strips applied along the downslope eave line, before application of the first course of roofing, intended to fill spaces between cutouts and joints of the first course.

Static Load: any load, as on a structure, that does not change in magnitude or position with time.

Steel Joist (open web steel joist): normally used as a horizontal supporting member between beams or other structural members, suitable for the support of some roof decks.

Steep Asphalt: Type lil Asphalt. (See Asphalt.)

Steep-Slope Roof: a roof of suitable slope to accept the application of water shedding roofing materials.

Steep-Slope Roofing: a category of roofing that includes water shedding types of roof coverings installed on slopes exceeding 3:12 or 25%.

Steeple: a tower or spire, usually located on a church.

Step Flashing: individual pieces of material used to flash walls, around chimneys, dormers, and such projections along the slope of a roof. Individual pieces are overlapped and stepped up the vertical surface.

Stick Clip: in waterproofing, a non-penetrating fastener that is adhered to the waterproofing surface; typically used to retain insulation, drainage panels, prefabricated protection materials, etc., against the waterproofing to prevent sliding and displacement.

Stiffener Rib: small intermediate bends in a metal pan used to strengthen the panel.

Storm Anchor: see Wind Clip.

Strain: the dimensionless expression for the elongation of a material under stress. Strain is expressed as the ratio of elongation per unit length.

Strapping (felts): a method of installing roofing rolls or sheet good materials parallel with the slope of the roof.

Straw Nail: a long-shanked nail. Sometimes used for fastening over tile at hips and ridges.

Stress: the internal resistance of a material to a force, measured as a force per unit area.

Stress-Crack: external or internal cracks within a material caused by long-term stress. Environmental factors, such as contact with corrosive material, usually accelerate stress-cracking.

Strike-Through: a term used in the manufacture of fabric-reinforced polymeric sheeting to indicate that two layers of polymer have made bonding contact through the scrim or reinforcement.

Strip Mopping: see Mopping.

Strip Shingles: asphalt shingles that are manufactured in strips, approximately three times as lone as they are

Strippable Films: (for metal) added protection of plastic films sometimes applied to coated or finished metals after the coil coating process. Applied after prime and top coats to resist damage to the finish prior to and during shipping, fabrication, and installation.

Stripping or Strip-Flashing: membrane flashing strips used for sealing or flashing metal flashing flanges into the roof membrane.

Stripping In: application of membrane stripping ply or plies.

Structural Panel: a panel designed to be applied over open framing in which a structural deck is not required.

Styrene Butadiene Rubber: high molecular weight polymers having rubber-like properties, formed by the random copolymerization of styrene and butadiene monomers.

Styrene Butadiene Styrene Copolymer (SBS): high molecular weight polymers that have both thermoses and thermoplastic properties, formed by the block copolymerization of styrene and butadiene monomers. These polymers are used as the modifying compound in SBS polymer modified asphalt roofing membranes to impart rubber-like qualities to the asphalt.

Substrate: the surface upon which the roofing or waterproofing membrane is applied (e.g., in roofing, the structural deck or insulation).

Sump: an intentional depression around a roof drain or scupper that serves to promote drainage.

Superimposed Loads: loads that are added to existing loads. For example, a large stack of insulation boards placed on top of a structural steel deck.

Surface Conductance: a unit of heat flow or heat exchange between a material and the air around it. Ventilation over a surface will decrease the thickness of the air film and reduce the thermal effect (increase the heat flow).

Surface Cure: curing or vulcanization that occurs in a thin layer on the surface of a manufactured polymeric sheet or other items.

Surface Dryness: surface dryness can be evaluated qualitatively by taping an 18 inch by 18 inch (0.46 m by 0.46 m) clear 4 mil polyethylene sheet to a concrete surface, and observing the moisture that may collect on the underside of the polyethylene sheet. Additional details of this procedure may be found in ASTM D 4263.

Surface Erosion: the wearing away of a surface due to abrasion, dissolution, or weathering.

Surface Texture: the resulting surface from the final pass of SPF. The following terms are used to describe the types of SPF surfaces: smooth surface texture, orange peel surface texture, coarse orange peel surface texture, verge of popcorn texture, popcorn surface texture, treebark surface texture, and oversprayed surface texture.

Surfacing: the top layer or layers of a roof covering, specified or designed to protect the underlying roofing from direct exposure to the weather.

Surfactant: short for "surface active agent." Used to alter the surface tension of liquids. An ingredient in SPF formulations to aid in mixing and controlling cell size.

SWRI: Sealant, Waterproofing and Restoration Institute

Synthetic Rubber: any of several elastic substances resembling natural rubber, prepared by the polymerization of butadiene, isoprene, and other unsaturated hydrocarbons. Synthetic rubber is widely used in the fabrication of single-ply roofing membranes.

Systems Builders Association: SBA


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