A pattern of hot bitumen
application in roughly circular
areas, generally about 18-inch
diameter, on a grid of unmopped,
A mopping pattern featuring
parallel mopped bands.
A random pattern of bitumen beads
hurled onto the substrate from a
broom, mop, or machine.
Nailer. A wood member bolted or otherwise anchored to a deck or
wall to provide nailing anchorage of membrane roof felts or
Neoprene. A synthetic rubber (chemically polychloroprene) used
in fluid or sheet-applied elastomeric single-ply roof membranes
One-on-one. Non-shingled application pattern of a single ply of
felt followed by application of a second ply (see Phased
Carbon and hydrogen atom matter of plant or animal
Parting Agent. Powdered mineral (talc, mica, etc.) placed on
coated felts to prevent adhesion of concentric felt layers in the
roll (sometimes called a releasing agent or anti-stick compound).
Perlite. An aggregate used in lightweight insulating concrete
and in preformed insulating board, formed by heating and
expanding siliceous volcanic glass.
Perm. A unit of water-vapor transmission, defined as 1 grain of
water vapor per square foot per hour per inch of mercury pressure
difference. (1 in. Hg = 0.491 psi.)
Permeance. An index of a material's resistance to water-vapor
transmission. (See Perm)
Phased application. The practice of applying the felt plies of a
roofing or waterproofing membrane in two or more operations.