01 May 1999
10-6m) to 1/4 in. diameter, used to surface BUR
direction. Two or more plies laminated with grain
or modified bitumen cap sheets, asphalt
direction parallel is a "parallel laminated layer".
shingles, and some cold process membranes.
Leno fabric--An open fabric in which two warp
Model Codes--Codes established to provide
yarns wrap around each fill yarn in order to
uniformity in regulations pertaining to building
prevent the warp or fill yarns from sliding over
Live load--Live load means all loads including
Uniform Building Code published by lCBO
snow, exerted on a roof except dead, wind, and
National Building Code by BOCA
Standard Building Code by SBCCI
International Building Code (New)
Loose-laid membrane--A unadhered roofing
membrane anchored to the substrate only at the
edges and penetrations through the roof and
(nominal) to corresponding strain below the
ballasted against wind uplift by loose aggregate
proportional limit of a material, expressed in
force per unit area based on the minimum initial
cross sectional area.
Macromolecule--A large molecule in which
there is a large number of one or several
Moisture conduction--Migration by wicking as
relatively simple chemical units, each consisting
contrasted to vapor movement.
of several atoms bonded together.
Moisture contour map--A map with lines
Masonry--Anything constructed of materials
connecting continuous levels of moisture. When
such as bricks, concrete blocks, ceramic blocks,
drawn by computer the wettest areas are often
indicated by darkest symbols and the driest
areas left blank.
Mastic--Caulking or sealant normally used in
sealing roof panel laps.
Mole run--A meandering ridge in a membrane
not associated with insulation or deck joints.
Membrane--A flexible or semi-flexible roof
covering or waterproofing whose primary
Monomer--A simple molecule which is capable
function is the exclusion of water.
of combining with a number of like or unlike
molecules to form a polymer.
Memory--Tendency of a material to regain a
previous configuration--notably, the tendency of
Mop-and-flop--A procedure in which roof
glass-fiber felts not to lie flat on their substrate
components (insulation boards, felt plies, cap
after unrolling; the retraction of single-ply roll
sheets, etc.), are initially placed upside down
goods which were stretched during production or
adjacent to their ultimate locations, are coated
with adhesive, and are then turned over and ad-
hered to the substrate.
Mer--The repeating structural unit of any high
Mopping--Application of hot bitumen with a mop
Mesh--The square opening of a sieve.
or mechanical applicator to the substrate or to
the plies of a built-up or modified-bitumen roof.
There are four types of mopping: (1) solid--a
Metal flashing--See Flashing--frequently used
continuous coating; (2) spot--bitumen is applied
as through-wall cap, or counterflashing.
in roughly circular areas, generally about 460
mm (18 in.) in diameter, leaving a grid of
Mineral Fiber--Inorganic fibers
unmopped, perpendicular area, (3) strip--
asbestos or mineral wool (slag).
bitumen is applied in parallel bands, generally
200 mm (8 in.) wide and 300 mm (12 in) apart;
(4) sprinkle--bitumen is shaken on the substrate
aggregate, ranging in size from 500m (1m =