Term Description
Spot mopping

See "mopping, spot."

Spray polyurethane foam (SPF)

A foamed plastic material, formed by mixing and spraying two components—isocyanate (‚"A-component‚") and resin containing a polyol (‚"B-component‚") to form a rigid, fully adhered, water-resistant, insulating membrane.


Single Ply Roofing Industry.


(1) A unit used in measuring roof area equivalent to 100 square feet; (2) a quantity of material sufficient to cover 100 square feet of a roof deck.


(1) A blade of leather or rubber set on a handle and used for spreading, pushing or wiping liquid material on, across or off a surface; (2) to smooth, wipe or treat with a squeegee.


Temporary or permanent discoloration to the surface of a roof membrane, coating or other covering caused by foreign material on the surface.

Stainless steel

An alloy of steel that contains chromium and also may contain nickel or copper; generally, has good resistance to corrosion.

Standing seam

In metal roofing, a type of seam between adjacent sheets of material made by turning up the edges of two adjacent metal panels and 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 water-shedding roof coverings, the starter course is covered by the first course.

Starter sheet

(1) Felt, ply sheet or membrane strip that is made or cut to a width narrower than the standard width of the roll material and used to start the shingling pattern at a roof edge; (2) particular width sheet 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 the first course of roof covering and intended to fill spaces between cutouts and joints of the first course.


A malleable alloy of iron and carbon produced by melting and refining pig iron and/or scrap steel; graded according to the carbon content (in a range from 0.02 percent to 1.7 percent); other elements, such as manganese and silicon, may be included to provide special properties.

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

See "asphalt, steep."

Steep-slope roofs

A category of roofing that generally includes water-shedding types of roof coverings installed on slopes exceeding 3:12.

Step flashing

Individual pieces of sheet-metal 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 nonpenetrating 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.

Stone wool

Insulation composed principally of fibers manufactured from rock, slag or glass, with or without binders.

Strapping (felts)

A method of installing roofing rolls or sheet good materials parallel with the slope of the roof.


(1) A measure of the load on a structural member in terms of force per unit area; (2) the force acting across a unit area in solid material in resisting the tension, compression or shear that tends to be induced by external forces; (3) the ratio of applied load to the initial cross-sectional area.

Strip flashing

Membrane flashing strips used for sealing or flashing metal flashing flanges into the roof or waterproofing membrane.

Strip shingles

Asphalt shingles that are manufactured in strips approximately three times as long as they are wide with or without cutouts.

Stripping in

Application of membrane stripping ply or plies.

Structural panel

A metal roof panel designed to be applied over open framing rather than a continuous or closely spaced roof deck.

Styrene butadiene styrene copolymer (SBS)

High molecular weight copolymer with thermoset and thermoplastic properties (thermoplastic elastomer), formed by the block copolymerization of styrene and butadiene monomers; used as the modifying compound in SBS polymer-modified asphalt roof membranes to impart rubberlike qualities to the asphalt.