A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | Y | Z
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.)
Beaufort Scale

Beaufort Number

International Description

Miles per Hour

Meters per Second

Description

0

Calm

Less than 1

Less than .5

Calm; smoke rises vertically.

1

Light Air

1-3

.5-1

Direction of wind shown by smoke but not by wind vanes.

2

Light Breeze

4-7

2-3

Wind on felt on face; leaves rustle; ordinary vane moved by wind.

3

Gentle Breeze

8-12

4-5

Leaves and small twigs in constant motion; wind extends light flag.

4

Moderate Breeze

13-18

6-7

Raises dust and loose paper; small branches are moved.

5

Fresh Breeze

19-24

8-10

Small trees in leaf begin to sway; crested wavelets form on inlet islands.

6

Strong Breeze

25-31

11-13

Large branches in motion; whistling heard in telegraph wires; umbrellas used with difficulty.

7

Moderate

(or near) gale

32-38

14-16

Whole trees in motion; inconvenience in waling.

8

Gale

(or fresh gale)

39-46

17-20

Breaks twigs off trees; generally impedes progress.

9

Strong Gale

47-54

21-23

Slight structural damage occurs.

10

Storm

(or whole gale)

55-63

24-27

Trees uprooted; considerable damage occurs.

11

Violent Storm

64-72

28-31

Accompanied by widespread damage.

12

Hurricane

73*-136

32-60

Devastation occurs.

*The U.S. uses 74 statute mph as the speed criterion for hurricanes.

Reference:  1993 Roofing Materials Guide.  Original scale developed in 1805 by British naval officer Sir Francis Beaufort.

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.
   
...Back Next...
 
 
Copyright © 2005-2010 - Armko Industries, Inc. All Rights Reserved.