Chlorinated polyethylene. Synthetic rubber, used for single-ply
membranes, composed of high-molecular-weight polyethylene,
chlorinated to impart elasticity.
Chlorosulfonated polyethylene. Synthetic rubber based on high
molecular-weight polyethylene with pendant sulphonyl chloride.
Coal-tar pitch. Dark brown to black solid hydrocarbon obtained
from the residuum of distilled coke-oven tar, used as
waterproofing agent of dead level or low-slope built-up roofs.
Cold-process roofing. A bituminous membrane comprising layers of
saturated felts bonded with cold-applied asphalt roof cement and
surfaced with a cutback or emulsified asphalt roof coating.
Crack. A membrane fracture produced by bending, often at a ridge
Creep. (l) Permanent elongation or shrinkage of the membrane
resulting from thermal or moisture changes. (2) Permanent
deflection of structural framing or structural deck resulting
from plastic flow under continued stress or dimensional changes
accompanying changing moisture content or temperature.
Cricket. Ridge, triangular in cross section, built-up in flat
valley or perimeter to direct rainwater to a drain.
Crosslinking. Chemical bond formed between long-chain molecules
in cured polymers.
Curing. The final step in the irreversible polymerization of a
thermosetting plastic, requiring a combination of heat,
radiation, and pressure.
Cutback. Solvent-thinned bitumen used in cold-process roofing
adhesives, flashing cements, and roof coatings.
Cutoff. A detail designed to prevent lateral water movement into
the insulation where the membrane terminates at the end of a
day's work or at an isolated roof section, usually removed before
Absolutely horizontal, or zero slope (See Slope).
Structural supporting surface of a roof system.