| BACKGROUND
COUNT |
|
The reading of a nuclear
density meter before the material to be
tested or identified is introduced. |
| BACKNAILING |
|
(1) The practice of
blind-nailing all the plies of a substrate
or roofing felts to a substrate in addition
to hot-mopping to prevent slippage; (2)
The practice of blind-nailing roofing felts
to a substrate in addition to hot-mopping
to prevent slippage; (3) "Blind"
(i.e., concealed by overlapping felt) nailing
in addition to hot mopping to prevent membrane
slippage; (3) The practice of nailing the
back portion of a roofing ply, steep roofing
unit or other components in a manner so
that the fasteners are covered by the next
sequential ply, course, and are not exposed
to the weather in the finished roof system.
See BLIND NAILING. |
| BACKSCATTER |
|
The number of neutrons
reflected back as contrasted to passing
through a substance. Usually referring to
nuclear testing devices. |
| BACK SURFACING |
|
Fine mineral matter
applied to the back side of shingles and
roll roofing to keep them from sticking
together while packaged. |
| BACKUP
PLATE |
|
A rigid plate to support
an end lap to provide uniform compression. |
| BACK WATER
LAP |
|
A lap installed in
such a manner as to oppose the flow of water. |
| BALCONY,
EXTERIOR |
|
A landing or porch
projecting from the wall of a building. |
| BALD ROOF |
|
See SMOOTH-SURFACED
ROOF. |
| BALLAST |
|
(1) Aggregate, concrete
pavers, or other material designed to prevent
wind uplift or flotation of a loose laid
roof system; (2) An anchoring material,
such as aggregate or precast concrete pavers,
which employs the force of gravity to hold
(or assist in holding) single-ply roof membranes
in place; (3) An aggregate for application
over single-ply, loose-laid roofing system.
Alternate method of securing single-ply
to roof. |
| BALUSTRADE |
|
An entire railing system
(as along the edge of a balcony) including
a top rail and it balusters, and sometimes
a bottom rail. |
| BANBURY
MIXER |
|
A heavy-duty batch
mixer with two counter-rotating rotors.
Used mainly in the rubber industry. |
| BARGEBOARD |
|
A board which hangs
form the projecting end of a roof, covering
the gables, often ornamental. Also referred
to as Vergeboard. |
| BAR JOISTS |
|
(Open web joist) Normally
used as beams or horizontal structural members
suitable for the support of floors or roof
decks, with members made of tees, pairs
of angles, round bars or tubing. See STEEL
JOIST. |
| BARREL
VAULT |
|
A building profile
featuring a rounded profile to the roof
on the short axis, but with no angle change
on a cut along the long axis. |
| BARRIER
PROTECTION |
|
Protection from the
environment by a physical, inert barrier.
If the barrier is broken, the underlying
base metal is unprotected. Contrasts with
anodic coatings, which, if breached, continue
to protect underlying base metal. |
| BASE FLASHING |
|
(1) Connecting devices
that seal membrane joints at walls, expansion
joints, drains, gravel stops, and other
places where the membrane is interrupted.
Base flashing forms the upturned edges of
the watertight membrane; (2) That portion
of the flashing attached to or resting on
the deck to direct the flow of water onto
the roof covering; (3) (Membrane Base Flashing):
Plies or strips of roof membrane material
used to close off and/or seal a roof at
the roof to vertical intersections, such
as at a roof to wall juncture. Membrane
base flashing covers the edge of the field
membrane. See FLASHING. |
| BASEMENT |
|
That portion of a building
between floor and ceiling, which is so located
that one-half or more of the clear height
is below grade. |
| BASE PLY |
|
(1) The lowermost or
first ply of roofing material in a roof
membrane assembly; (2) The lowermost ply
of roofing in a roof membrane or roof system.
See BASE SHEET. |
| BASE SHEET |
|
(1) A saturated or
coated felt placed as the first (non-shingled)
ply in some multi ply, built up roof membranes;
(2) An impregnated, saturated or coated
felt placed as the first ply in some multi-ply
built-up and modified bitumen roof membranes.
See BASE PLY. |
| BASE TIME |
|
The date to which all
future and past benefits and costs are converted
when a present-value method is used (usually
beginning of study period). |
| BASIC
FLOOD ELEVATION |
|
The elevation of flooding
including wave height having a 1% chance
of being equaled or exceeded in any given
year. |
| BASIC
WIND SPEED |
|
A 3 second gust speed
at 33 feet above ground and associated with
an annual probability of 0.02 being equaled
or exceeded. |
| BATTEN |
|
(1) A strip of steel
or aluminum used to mechanically fasten
a single ply membrane for the purpose of
preventing wind uplift; (2) A raised rib,
in a metal roof, or a separate part of formed
portion in a metal roofing panel; (3) Cap
or cover; (4) In a metal roof: A metal closure
set over or covering the joint between,
adjacent metal panels; (5) Wood: A strip
of wood usually set in or over the structural
deck, used to elevate and/or attaché
a primary roof covering such as tile; (6)
In a membrane roof system: A narrow plastic,
wood or metal bar which is used to fasten
or hold the roof membrane and/or base flashing
in place. |
| BATTEN
BAR OR STRIP |
|
Compressive device
used to assist in retaining membrane. |
| BATTEN
SEAM |
|
A seam in metal roofing
which is formed around a wood strip. |
| BAY |
|
The space between frame
center lines or primary supporting members
along the main axis of a building. |
| BEAM |
|
A primary member, usually
horizontal, that is subjected to bending
loads. There are three types: simple, continuous
and cantilever. |
| BEAM AND
COLUMN |
|
A primary structural
system consisting of a series of beams supported
by columns. Used as the interior frame system
on many preengineered building systems. |
| BEARING
PLATE |
|
A steel plate that
is set on top of a support on which a beam
or purlin can rest. |
| BEAUFORT
SCALE |
|
A scale in which the
force of the wind is rated on a scale of
0 to 12. (See Beaufort Scale chart below.) |
|
| BELL
CURVE |
|
The shape of a curve
depicting the distribution of results from
data following a normal or Gaussian distribution. |
| BELL
ROOF |
|
A roof whose cross
section is shaped like a bell. |
| BELVEDERE |
|
(1) An open, roofed
gallery in an upper story, built for providing
a viewpoint; (2) A gazebo. |
| BID |
|
An offer submitted
by a contractor to a prospective client
covering the cost of completing a specified
job. Bids may be for labor or materials
or both. |
| BID
BOND |
|
A document sometimes
required of bidders to provide some assurance
that the bidder will enter into a contract
within a specified period of time and will
furnish the required bonds for performance
and labor and materials payment. |
| BILL
OF MATERIALS |
|
A list of items or
components used for fabrication, shipping,
receiving and accounting purposes. |
| BIRD
BATH |
|
(1) Random, inconsequential
amounts of residual water on a roof membrane;
(2) Shallow accumulations of water which
will dissipate only due to evaporation. |
| BIRD
SCREEN |
|
Wire mesh used to prevent
birds from entering the building through
ventilators, louvers and other openings
on the exterior of a building. See INSECT
SCREEN. |
| BIRDSTOP |
|
|
| BITUMEN |
|
(1) A generic term
applied to amorphous, semi solid mixtures
of predominantly hydrocarbons in viscous
or solid form, derived from coal or petroleum.
This term is normally used to describe either
coal-tar pitch or asphalt; (2) The generic
term for an amorphous, semi-solid mixture
of complex hydrocarbons derived from any
organic source. Asphalt and coal-tar are
the two commonly used bitumens used in the
roofing industry; (3) Generic term for an
amorphous, semi-solid mixture of complex
hydrocarbons derived from petroleum or coal.
In the roofing industry there are two basic
bitumens: asphalt and coal-tar pitch. Before
application, they are (a) heated to liquid
state; (b) dissolved in a solvent; or (c)
emulsified; (4) A class of amorphous, black
or dark colored, (solid, semi-solid or viscous)
cementitious substances, natural or manufactured,
composed principally of high molecular weight
hydrocarbons, soluble in carbon disulfide,
and found in asphalts, tars, pitches and
asphaltites; (5) A class of amorphous, black
or dark colored (solid, semi-solid or viscous)
cementitious substances, natural or manufactured,
composed principally of high molecular weight
hydrocarbons, soluble in carbon disulfide,
and found in petroleum asphalts, coal-tars
and pitches, wood tars and asphalts; (6)
A generic term used to denote any material
composed principally of bitumen, typically
asphalt or coal-tar. |
| BITUMEN
STOP |
|
See ENVELOPE
and BLEED SHEET. |
| BITUMEN
TRAP |
|
(1) A continuous membrane
edge formed at the perimeter and at penetrations
by folding the base sheet or ply over the
plies above and securing it to the top of
the membrane. The envelope prevents bitumen
seepage from the edge of the membrane; (2)
A continuous felt fold formed by wrapping
and securing a portion of a base felt back
up and over the felt plies above it. Envelopes
help prevent the seepage of bitumen; (3)
Continuous edge formed by folding an edge
base felt over the plies above and securing
it to the top felt. The envelope thus prevents
bitumen seepage through the exposed edge
joints of the laminated, built up roofing
membrane. See ENVELOPE. |
| BITUMINOUS |
|
Containing or treated
with bitumen. Examples: bituminous concrete,
bituminous felts and fabrics, bituminous
pavement. |
| BITUMINOUS
EMULSION |
|
(1) A suspension of
minute globules of bituminous material in
water or in an aqueous solution; (2) A suspension
of minute globules of water or an aqueous
solution in a liquid bituminous material
(invert emulsion); (3) a suspension of minute
particles of bituminous material in water
or other aqueous solution. See ASPHALT
EMULSION. |
| BITUMINOUS
GROUT |
|
A mixture of bituminous
material and fine sand that, when heated,
will flow into place without mechanical
manipulation. |
| BLACKBERRY |
|
A small bubble or blister
in the flood coating of a gravel surfaced
roof membrane (sometimes referred to a blueberry
or tar-boil). |
| BLACK
BODY |
|
A theoretical object
that absorbs all the radiant energy falling
on it and emits it in the form of thermal
radiation. |
| BLANKET
(BATT) INSULATION |
|
(1) Fiberglass or other
compressible fibrous insulation, generally
available in roll form; (2) Fibrous glass
insulation in roll form, often installed
between the metal roof panels and the supporting
purlins or attic. |
| BLEED
SHEET |
|
A sheet metal material
used to prevent the migration of bitumen. |
| BLIND
NAILING |
|
(1) The practice of
nailing the back unexposed portion of a
roofing ply in a manner that the fasteners
are not exposed to the weather in the finished
product; (2) The use of nails that are not
exposed to the weather in the finished roofing
system. See BACKNAILING
and NAILING. |
| BLIND
RIVET |
|
A small-headed pin
with expendable shank for joining light-gauge
metal. Typically used to attach flashing,
gutter, etc. Applied from one side, with
a stem that pulls against material on the
blind side. |
| BLISTER |
|
(1) An enclosed pocket
of air mixed with water or solvent vapor,
trapped between impermeable layers of felt
or membrane, or between the felt and substrate
or between the membrane and substrate; (2)
A spongy raised portion of a roof membrane,
ranging in area from 1" in diameter
and of barely detectable height upwards.
Blisters result from the pressure build-up
of gasses entrapped in the membrane system.
These gasses most commonly are air and/or
water vapor. Blisters usually involve delamination
of the underling membrane plies; (3) Spongy,
humped portion of a roof membrane, formed
by entrapped air-vapor mixture under pressure,
with the blister chamber located either
between felt plies or at the membrane-substrate
interface; (4) Bubbles that may appear on
the surface of asphalt roofing after installation. |
BLISTER
(POLYURETHANE FOAM) |
|
An undesirable rounded
delamination of the surface of a polyurethane
foam whose boundaries may be either more
or less sharply defined. |
| BLOCKING |
|
(1) Wood built into
a roofing system above the deck and below
the membrane and flashing to stiffen the
deck around an opening, act as a stop for
insulation, or to serve as a nailer for
attachment of the membrane or flashing;
(2) Continuous wood components anchored
to the deck at roof perimeters and openings,
and doublings used as cross sectional fillers
and anchorage bases, used in conjunction
with nailers; (3) Sections of wood (which
may be preservative treated) built into
a roof assembly, usually attached above
the deck and below the membrane or flashing,
used to stiffen the deck around an opening,
act as a stop for insulation, support a
curb or to serve as a nailer for attachment
of the membrane and/or flashing. |
BLOCK
OR BOARD
THERMAL INSULATION |
|
Rigid or semi-rigid
thermal insulation units manufactured at
predetermined sizes, typically square or
rectangular. |
| BLOOM |
|
A visible exudation
of efflorescence on the surface of a material. |
| BLOWING
AGENT |
|
(1) An expanding agent
used to produce a gas by chemical or thermal
action or both, in manufacturer of hollow
or cellular materials; (2) A compounding
ingredient used to produce gas by chemical
or thermal action, or both, in manufacture
of hollow or cellular articles. |
| BLUEBERRY |
|
See STRAWBERRY. |
| BOCA |
|
Building Officials
and Code Administrators, International,
Inc., 4051 W. Flossmer Road, Country Club
Hills, IL 60478-5795 (author of the BOCA
National Building Code). |
BODIED
SOLVENT
ADHESIVE |
|
An adhesive consisting
of a solution of the membrane compound in
solvent, used in the seaming of membranes. |
| BOMA |
|
Building Owners &
Managers Association, International. |
| BOND |
|
(1) The adhesive and
cohesive forces holding two roofing components
in intimate contact; (2) A surety. Typical
types are bid, performance and payment,
and warranties; (3) The adhesive and/or
cohesive forces holding two components in
positive contact. |
| BONDING
AGENT |
|
A chemical substance
applied to a suitable substrate to create
bond between it and a succeeding layer. |
| BOOT |
|
(1) A covering made
of flexible material, which may be preformed
to a particular shape, used to exclude dust,
dirt, moisture, etc. from around a penetration;
(2) A bellows-type covering to exclude dust,
dirt, moisture, etc., from a flexible joint.
(3) A flexible material used to form a closure,
sometimes installed at inside and outside
corners. |
| BOSTON
HIP OR RIDGE |
|
A style of finishing
a shingle, slate, or tile hip roof; the
shingles are laid in two parallel rows which
overlap at the hip. Alternate courses overlap
in opposite directions, providing a weatherproof
joint. |
| BOX
CUTTER |
|
A gutter usually lined
with metal, asphalt, or roofing felt which
may be concealed behind the eaves or run
along a valley. |
| BRACE
RODS |
|
Rods or cables used
in roof and walls to transfer loads, such
as wind loads, and seismic and crane thrusts
to the foundation. (Also, often used to
plumb buildings but not designed to replace
erection cables). |
| BRACING |
|
Structural elements
installed to provide restraint or support
(or both) to other members, so that the
complete assembly forms a stable structure.
May consist of knee braces, cables, rods,
struts, ties, shores, diaphragms, rigid
frames, etc. |
| BRAIN |
|
Roofer's slang for
membrane, usually fiberglass mesh used with
roof cement for repairs of built-up roofing. |
| BRAKE |
|
Hand or power-activated
machinery used to form metal. |
| BREAKING
FACTOR |
|
In testing, the tensile
load or force required to rupture textiles
(e.g. fibers, yarn, reinforcements) or leather. |
| BREAKING
STRAIN |
|
Percent elongation
at which a sheet or other tested component
ruptures under tensile force. |
| BREAKING
STRESS |
|
Stress (in force per
linear or area unit) at which a sheet or
other tested component ruptures under tensile
force. |
| BRERWULF |
|
Building Research Establishment
Real-time Wind Uniform Load Follower. Title
refers to the first dynamic wind testing
machine installed in the United States.
This device is manufactured and distributed
by BMT Fluid Mechanics, Ltd., England, under
license from the U.K. Building Research
Establishment. |
| BRICK |
|
A solid masonry unit
not larger than 16 x 4 x 8, usually smaller
and composed of clay and hardened by burning
in a kiln. |
| BRIDGING |
|
(1) When the membrane
is unsupported at a juncture; (2) Bridging
in steep slope roofing is a method of reroofing
over standard sized asphalt shingles with
metric-sized asphalt shingles. |
| BRITTLENESS |
|
Lack of ductility. |
| BROOMING |
|
(1) Embedding a ply
of roofing material by using a broom to
smooth out the ply and ensure contact with
the adhesive under the ply; (2) Field procedure
of pressing felts into a layer of fluid
hot bitumen to ensure continuous adhesion,
i.e., elimination of blister originating
voids--of the bitumen film; (3) An action
carried out to facilitate embedment of a
ply of roofing material into hot bitumen
by using a broom, squeegee or special implement
to smooth out the ply and ensure contact
with the bitumen or adhesive under the ply. |
| BTU |
|
British Thermal
Unit -- The heat energy required
to raise the temperature of one pound of
water 1? F (joule). |
| BTUH |
|
Btu per hour. |
| 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 the roof assembly. |
| BUILDER/CONTRACTOR |
|
A general contractor
or subcontractor responsible for providing? |
| BUILDING |
|
A structure that encloses
space; a structure that gives shelter or
protection for any occupancy. |
| BUILDING
CODE |
|
(1) Published regulations
and ordinances established by a recognized
agency prescribing design loads, procedures,
and construction details for structures.
Usually applying to designated jurisdictions
(city, county, state, etc.). Building codes
control design, construction, and quality
of materials, use and occupancy, location
and maintenance of buildings and structures
within the area for which the code has been
adopted; (2) The minimum construction requirements
established generally by national organizations
of experts and adopted completely or in
altered form by local governing authorities. |
| BUILDING
ENVELOPE |
|
Exterior of a building. |
| BUILDING
OFFICIAL |
|
That official designated
by the appointing authority to enforce the
provisions of the building code and other
applicable laws. |
| BUILT-UP
ROOF COVERING |
|
Two or more layers
of felt cemented together and surfaced with
a cap sheet, mineral aggregate, smooth coating
or similar surfacing material. |
| BUILT-UP
ROOF (BUR) MEMBRANE |
|
(1) 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; (2)
Continuous, semi flexible roof covering
of laminations or plies of saturated or
coated felts alternated with layers of bitumen,
surfaced with mineral aggregate or asphaltic
materials. Also referred to as composition
roofing and gravel roofing; (3) A continuous,
semi flexible multi ply roof membrane, consisting
of plies or layers of saturated felts, coated
felts, fabrics or mats between which alternate
layers of bitumen are applied. Generally,
built up roof membranes are surfaced with
mineral aggregate and bitumen, a liquid
applied coating or a granule surfaced cap
sheet. |
| BUILKHEAD |
|
(1) The portion of
the exterior walls of a building which is
located immediately under show-windows;
(2) A structure above the roof of any building,
enclosing a stairway, tank, elevator machinery
or ventilating apparatus, or such part of
a shaft as extends above a roof. |
| BULL |
|
Roofer's term for plastic
cement. |
| BUNDLE |
|
A package of shingles.
There are 3, 4 or 5 bundles per square.
|
| BUR |
|
Abbreviation sometimes
used for built-up roofing membrane. |
| BUTT
EDGE |
|
(1) The lower edge
of the shingle tabs; (2) The lower, exposed
edge of a shingle. |
| BUTT
JOINT |
|
A joint formed by adjacent,
separate sections of material, such as where
two neighboring pieces of insulation abut. |
| BUTT
ROLL |
|
Portion of a roll of
felt. |
| BUTYL |
|
(1) 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; (2) Secondary radioactive material
derived from nuclear refining processes
in the manufacture of nuclear fuels. This
type of material is used in nuclear moisture
meters. |
| BUTYL
RUBBER |
|
A synthetic elastomer
based on isobutylene and a minor amount
of isoprene. It is vulcanizable and features
low permeability to gases and water vapor. |
| BUTYL
TAPE |
|
A sealant tape sometimes
used between metal roof panel seams, and
end laps; also used to seal other types
of sheet metal joints, and in various sealant
applications. |
| |
|
|
