| Backnailing |
the
practice of blind nailing (in addition to hot mopping)
all the plies of a substrate to prevent slippage. (See
BLIND NAILING.)
|
| Ballast |
an anchoring material, such as
aggregate, precast pavers, which employ the force of
gravity to hold (or assist in holding) membranes in
place. |
| Base Flashing |
see FLASHING.
. |
| Base Ply |
the base ply is
the first ply when it is a separate ply and not part
of a shingled system. |
| Base Sheet |
a saturated or coated felt placed
as the first ply in some multi-ply built up roof membranes. |
| Bentonite |
a clay formed from decomposed
volcanic ash, with a high content of the mineral montmorillonite;
has the capacity of absorbing a considerable amount
of water, and swells accordingly. |
| Bitumen |
the generic term for an amorphous,
semi-solid mixture of complex hydrocarbons derived
from any organic source. Asphalt and coal tar are the
two used in the roofing industry. |
| Bituminous |
containing or treated with bitumen.
Examples: bituminous concrete, bituminous concretes,
bituminous felts and fabrics, bituminous pavement. |
| Bituminous Grout |
a mixture of bituminous material
and fine sand that will flow into place without mechanical
manipulation when heated. |
| Blind Nailing |
the practice of nailing the back
portion of a roofing ply. |
| Blister |
a spongy raised portion of a
roof membrane, ranging in area from 1 inch in diameter
and of barely detectable height upward. Blisters result
from the pressure buildup of gases entrapped in the
membrane system. these gases most commonly are air
and/or water vapor. Blisters usually involve delamination
of the underlying membrane plies. |
| Bond |
the adhesive and cohesive forces
holding two roofing components in intimate contact. |
| Boot |
covering of flexible material,
which may be preformed to a particular shape, used
to seal around a penetration. |
| Brooming |
embedding a ply of roofing material
by using a broom to smooth out the ply and ensure contact
with the adhesive under the ply. |
| BTU |
(British Thermal Unit) - the
heat energy required to raise the temperature of 1
pound of water 1 degree Fahrenheit. |
| Buckle |
an upward, elongated tenting
displacement of a roof membrane frequently occurring
over insulation or deck joints. A buckle may be an
indication of movement within a roof assembly, and
usually associated with improper installation. |
| Built-up Roof Membrane |
a continuous, semi-flexible roof
membrane assembly, consisting of plies of saturated
felts, coated felts, fabrics or mats between which
alternate layers of bitumen are applied, generally
surfaced with mineral aggregate, bituminous materials,
or a granule-surfaced roofing sheet. (Abbreviation:
BUR.) |
| Butyl |
a rubber like material produced
by copolymerizing isobutylene with a small amount of
isoprene, Butyl may be manufactured in sheets, or blended
with other elastomeric materials to make sealants and
adhesives. |
