Cudahy Roofing & Supply, Inc.


We cover the Midwest from Cudahy


We at Cudahy Roofing feel strongly in our clients being able to make an educated decision when it comes to repairing or replacing their roof. The following is a comprehensive list of roofing terms posted for your knowledge and benefit. Please vist our Home Page>

AGGREGATE

Crushed stone, slag or water-worn gravel that comes in a wide range of sizes.
Used to surface built-up roofs.

ALLIGATORING

A characteristic of asphalt which occurs during the aging process in which the loss
of volatile oils and the oxidation brought about by solar radiation produces a pattern
of cracks which resemble an alligator hide, because of the limited tolerance of
asphalt to thermal expansion or contraction.

ASPHALT

A dark brown to black, highly viscous, hydrocarbon produces from the residue left
after the distillation of petroleum, used as a waterproofing agent.

BALLAST

Weight used to protect single-ply roofs or to prevent blow off of systems which are
not adhered.

BACK NAILING

The practice of nailing roofing felts to the deck under the overlap, in addition to hot
mopping, to prevent slippage of felts.

BARE SPOTS

Small areas on a roof where the top membrane has become exposed to the
elements.

BARREL ROOF

A roof design which in cross section is arched.

BASE PLY

An asphalt-saturated and/or coated felt installed as the first ply with 4 inch laps in
a built-up roof system under the following felts which can be installed in a shingle
like fashion.

BATTEN PLATE

a formed piece of metal designed to cover the joint between two lengths of metal
edge.

BITUMEN

Any of various mixtures of hydrocarbons occurring naturally or obtained through the
distillation of coal or petroleum. (See Coat Tar Pitch and Asphalt)

BLISTER:

An enclosed raised spot evident on the surface of a roof. They are mainly caused
by the expansion of trapped air, water vapor, moisture or other gases. Blisters on
a roof may involve only the coating, one or more plies of felt or may involve the
whole membrane thickness.

BEAD

A semi-rounded strip (bead) of caulking material.

BEAM

A heavy main support structure, steel or wood running horizontally between
columns or load bearing walls.

BOND BREAKER

A substance or a tape applied between two adjoining materials to prevent adhesion
between them.

BRAKE METAL

Sheet metal that has been bent to the desired configuration.

BUILT-UP ROOF - BUR

A roof consisting minimally of a BUR membrane but may also include insulation, vapor
retarders and other components.

BUILT-UP ROOF MEMBRANE - BURM

A built-up roof consisting of plies or layers of roofing felt bonded together on site
with bitumen; either tar or asphalt.

BULB-TEE

A specialized steel reinforcing member which support form boards and reinforces
a gypsum deck, which when poured surrounds the Bulb-Tee.

BUTTERFLY ROOF

A roof assembly which pitches sharply from either side toward the center.

CANOPY

An overhanging roof.

CANT STRIP

A beveled support used at the intersection of the roof deck with vertical surfaces so
that bends in the roofing membrane to form base flashings can be made without
breaking the felts.

CAP SHEETS

One to four plies of felt bonded and top coated with bitumen that is laid over an
existing roof as a treatment for defective roofs.

CEMENT, ROOFING

A general term for a variety of trowelable mastics, asphalt or tar, which are used
during roof construction and repair.

CHALK (ing)

The resulting dust which occurs on a surface that is susceptible to Ultra Violet
degradation.

CHECKING

A pattern of surface cracks running in irregular lines. When found in the top pour
of an asphalt built-up roof, is the preliminary stage of alligatoring.

CLEAT

A device made of formed sheet metal which is mechanically attached onto
which the fascia flange of a metal edge is snapped, so as to protect against wind
uplift.

COAL TAR PITCH (Tar)

A bituminous material which is a by product from the coking of coal. It is used as the
waterproofing material for tar and gravel built-up roofing.

COATING

A layer of any brush consistency product spread over a surface for protection.

COLD APPLIED

Products that can be applied without heating. These are in contrast to tar or
asphalt which need to be heated to be applied.

COLD PATCH

A roof repair done with cold applied material.

COLLAR

A conical metal cap flashing used in conjunction with vent pipes or stacks usually
located several inches above the plane of the roof, for the purpose of shedding
water away from the base of the vent.

COMPATIBLE

Two or more substances which can be mixed or blended without separating,
reacting, or affecting either material adversely.

COMPONENT

Any one part of an assembly associated with construction.

COMPOSITE BOARD

An insulation board which has two different insulation types laminated together in
2 or 3 layers.

CONDUCTOR

A pipe for conveying rain water from the roof gutter to a drain, or from a roof drain
to the storm drain; also called a leader, downspout, or downpipe.

COOLING TOWER

A large device mounted on roofs, consisting of many baffles over which water is
pumped in order to reduce its temperature.

CORE

A small section cut from any material to show internal composition. The core was
taken from the roof to verify the construction of the existing roof system. The deck
is visable along with the insulation and the roof membrane (see construction
section). The core was then replaced and repaired immediately with the
appropriate mastic and fiberglas reinforcing mesh.

CORNICE

A horizontal projecting course on the exterior of a building, usually at the base of
the parapet.

CORROSION

The deterioration of metal by chemical or electrochemical reaction resulting from
exposure to weathering, moisture, chemicals or other agents or media.

CONTROL JOINT

A control joint controls or accommodates movement in the surface component of a
roof.

COPING

A construction unit placed at the top of the parapet wall to serve as a cover for the
wall.

CORRUGATED

Folded or shaped into parallel ridges or furrows so as to form a symmetrically wavy
surface.

COURSE

A single layer of brick or stone or other building material.

CRAZING

A series of hairline cracks in the surface of weathered materials, having a web-like
appearance.

CRICKET

The evaluation of a part of a roof surface as a means of promoting drainage of
water from behind an obstacle such as chimney.

CUPOLA

A small monitor or dome at the peak of a pitched roof.

CURB

A short wall or masonry built above the level of the roof. It provides a means of
flashing the deck equipment.

CUTBACK

Basic asphalt or tar which has been "cutback" with solvents and oils so that the
material become fluid.

CUT OFF

A piece of roofing membrane consisting of one or more narrow plies of felt usually
moped in hot to seal the edge of insulation at the end of a day's work.

DAVE

The name of the guy who compiled this glossary. I'm glad you are actually reading this.

DAMPPROOFING

A process used on concrete, masonry or stone surfaces for the purpose of repelling
water. Moisture vapor readily penetrates coatings of this type. The main purpose
of dampproofing is to prevent the coated surface from absorbing rain water while
allowing is to breathe moisture vapor out of the structure.

DEAD LOAD

The constant designed weight (of the roof) and any permanent fixtures attached
above or below.

DECK

The base surface to which a roof system is applied.

DEFLECT

To bend or deform under weight.

DEW POINT

The critical temperature at which vapor condenses from the atmosphere and forms
water.

DORMER

The house-like structure which projects from a sloping roof.

DOUBLE TEE

Refers usually to a precast roof deck panel poured with two fins in its underside to
impart flexural rigidity.

DOWNSPOUT

The metal pipe used to drain water from a roof.

DRAWING OUTLINE

A top view drawing, of a building or roof showing only the perimeter drawn to scale.

DRAWING DETAIL

A top view drawing, of a building or roof showing the roof perimeter and indicating
the projections and roof mounted equipment, drawn to scale.

DRIP EDGE

A device designed to prevent water from running back or under an overhang.

DRIPPAGE

Bitumen material that drips through roof deck joints, or over the edge of a roof deck.

DRY LAP

A term describing the absence of bitumen between the plies of felt at the overlap
in a BURM.

DRY SHEET

A ply mechanically attached to wood or gypsum decks to prevent asphalt or pitch
from penetrating the deck and leaking into the building below.

DUCT

A cylindrical or rectangular "tube" used to move air either from exhaust or intake.
The installation is referred to as "duct work".

EPDM

Ethylene Propylene Diene Monomer. A single ply membrane consistsing of
synthetic rubber; usually 45 or 60 mils. Application can be ballasted,
fully adhered or mechanically attached.

EAVE

The part of a roof which projects out from the side wall, or the lower edge of the part
of a roof that overhangs a wall.

EDGE METAL

A term relating to brake or extruded metal around the perimeter of a roof.

EFFLORESCENCE

The process by which water leeches soluble salts out of concrete or mortar and
deposits them on the surface. Also used as the name for these deposits.

ELASTOMERIC

A general term, any of the numerous flexible roof membranes that contain rubber
or plastic.

EMULSION

In roofing, a coating consisting of asphalt and fillers suspended in water.

END LAP

The amount or location of overlap at the end of a roll of roofing felts in the
application.

E.V.T. EQUI-VISCOUS TEMPERATURE

The critical temperature at which asphalt reaches the viscosity most favorable to
good adhesion when applied in a BUR.

EXPANSION COEFFICIENT

The amount that a specific material will vary in any one dimension with a change
of temperature.

EXPANSION JOINT

A device used to make up the motion of expansion and contraction. On large roofs
this provision for the movement of the materials forming the walls, roof deck and
roof covering is usually made by deliberately separating the building into sections,
and covering separation between adjacent sections with the expansion joint to allow
movement but keep out the weather. Expansion joints, unlike control joints,
penetrate through the roof deck.

EXTRUSION

An item formed by forcing a base metal (frequently aluminum) or plastic, at a
malleable temperature, through a die to achieve a desired shape.

EYEBROW

A flat, normally concrete, projection which protrudes horizontally from a building
wall; Eyebrows are generally located above windows.

FACADE

The front of a building. Frequently, in architectural terms an artificial or decorative
effort.

FACTORY MUTUAL FM

A major insurance agency who has established stringent guidelines for maximum
construction integrity as it relates to fire and environmental hazards.Their specifications
have become industry standards.

FASCIA

Any cover board at the edge or eaves of a flat, sloping, or overhanging roof which
is placed in a vertical position to protect the edge of the roof assembly.

FASTENERS

A general term covering a wide variety of screws and nails which may be used for
mechanically securing various components of a building.

FELT

A very general term used to describe composition of roofing ply sheets, consisting
of a mat of organic or inorganic fibers unsaturated, impregnated with asphalt or coal
tar pitch, or impregnated and coated with asphalt.

FIRE WALL

Any wall built for the purpose of restricting or preventing the spread of fire in a
building. Such walls of solid masonry or concrete generally sub-divided a building
from the foundations to two or more feet above the plane of the roof.

FISHMOUTH

A characteristic opening at the exposed lap edge of BUR felts due to loss of bond
or wrinkling of the felt.

FLAKE

A scale like particle. To lose bond from a surface in small thin pieces. Sometimes
a paint film "flakes".

FLASHING

Connecting devices that seal membrane joints at expansion joints, walls, drains, gravel
stops, and other places where the membrane is interrupted or terminated.

FLASHING BASE

The upturned edge of the watertight membrane formed at a roof termination point
by the extension of the felts vertically over the cant strip and up the wall for a
varying distance where they are secured with mechanical fasteners.

FLASHING, COUNTER

The formed metal secured to a wall, curb, or roof top unit to cover and protect the
upper edge of a base flashing and its associated fasteners.

FLASH POINT

The critical temperature at which a material will ignite.

FLASHING, THRU-WALL

Flashing extended completely through a masonry wall. Designed and applied in
combination with counterflashings, to prevent water which may enter the wall above
from proceeding downward in the wall or into the roof deck or roofing system.

FOLDED SEAM

In sheet metal work, a joint between sheets of metal wherein the edges of the
sheets are crimped together and folded flat.

FLAT SEAM

A seam at the junction of sheet metal roof components that has been bent at the
plane of the roof.

FLOP

Cutting of felts into strips, coating the deck side with bitumen and placing (flopping)
the felt onto the deck.

FLASHING, STEP

Individual small pieces of metal flashing material used to flash around chimneys,
dormers, and such projections along the slope of a roof. The individual pieces are
overlapped and stepped up the vertical surface.

FULLY ADHERED

A completely attached (adhered) roof membrane.

GABLE

The end of a building as distinguished from the front or rear side. The triangular
end of and exterior wall from the level of the eaves to the ridge of a double sloped
roof.

GAMBREL ROOF

A type of roof which has its slope broken by an obtuse angle, so that the lower
slope is steeper than the upper slope. A double sloped roof having two pitches.

GALVANIZE

To coat a metal with zinc by dipping in molten zinc after cleaning.

GAUGE

The thickness of sheet metal and wire, etc.

GLAZE COAT

A light, uniform mopping of bitumen on exposed felts to protect them from the
weather, pending completion of the job.

GRANULES

The mineral particles of a graded size which are embedded in the asphalt coating
of shingles and roofing.

GRAVEL

Loose fragments of rock used for surfacing built-up roofs, in sizes varying from 1/8"
to 1 3/4".

GROUT OR GROUTING

A cement mortar mixture commonly used to fill joints and cavities of masonry. On
roof decks, the joints between many types of precast roof deck slabs are grouted
with cement grout.

GUTTER

Metal trough at the eaves of a roof to carry rain water from the roof to the
downspout.

GUTTER STRAP

Metal bands used to support the gutter.

GUY WIRE

A strong steel wire or cable strung from an anchor on the roof to any tall slender
projection for the purpose of support.

GYPSUM

A hydrated sulfate of calcium occurring naturally in sedimentary rock. In roofing,
a type of lightweight deck made from this pulverized rock.

HATCH

An opening in a deck; floor or roof. The usual purpose is to provide access from
inside the building.

HIP ROOF

A roof which rises by inclining planes from all four sides of a building.

INCOMPATIBILITY

Descriptive of two or more materials which are not suitable to be used together.

INSIDE DRAIN

A roof drain positioned on a roof at some location other than the perimeter. It
drains surface water inside the building through closed pipes to a drainage system.

INSULATION

Material which slows down or retards the flow or transfer of heat.

INSULATION FASTENERS

Any of several specialized mechanical fasteners designed to hold insulation down
to a steel or a nailable deck.

INSULATION VENT

A vent placed into the insulation which extends above the BURM.

INTERPLY

Between two layers of roofing felts that have been laminated together.

IRMA

Insulated (or Inverted) Roof Membrane Assembly. In this system the roof membrane is laid
directly on the roof deck, covered with extruded foam insulation and ballasted with stone,
minimum of 1000 lbs. per square.

JOIST

A horizontally placed timber or beam set on edge to give support to a floor or
ceiling.

KETTLE

Equipment used for heating bitumen to a flowing consistency.

KICK HOLE

A defect frequently found in perimeter flashings arising from being stepped on or
kicked. A small fracture of the base flashing in the area of the cant.

KRAFT

A heavy water resistant paper.

LADDER, FIXED

A ladder which is permanently attached to a building.

LAP

To extend one material partially over another; the distance so extended.

LEAD

A malleable metal once extensively used for flashings.

LEAN-TO-ROOF

the sloping roof of a building addition having its rafters or supports pitched against
and supported by the adjoining wall of a building.

LIQUID-APPLIED MEMBRANE

Generally applied to cast-in-place concrete surfaces in one or more coats to
provide fully-adhered waterproof membranes which conform to all contours.

MANSARD ROOF

A roof which rises by inclined planes from all four sides of a building. The sloping
roofs on all four sides have two pitches, the lower pitch usually very steep and the
upper pitch less steep.

MASTIC

A heavy trowel applied bitumen used for flashings or patch work which remains
elastic and pliable.

MELT POINT

The temperature at which the solid asphalt becomes a liquid.

MEMBRANE

A generic term relating to a variety of sheet goods used for certain built-up roofing
repairs and application. Also used to describe the combination of felts and
moppings of bitumen forming a single flexible unit and waterproofing system of a
BUR.

LIVE LOAD

The weight superimposed by snow or water or other tangibles which lack
permanency, not including the wind load, on a roof.

LOOSE LAID

A membrane "laid loosely", i.e., not adhered, over a roof deck or BURM.

METAL EDGE

Brake metal or metal extrusions which are secured at the perimeter of BURM to
form a weathertight seal.

MIL THICKNESS

Measurement used to determine thickness of a coating. 1 mil = .001 inch (1/1000).

MINERAL SPIRITS

A by-product of petroleum, clear in color, a solvent for asphaltic coatings.

MINERAL SURFACED

A heavy roofing felt that has very small granules embedded across its surface.

MODIFIED BITUMEN

Bitumen modified by special processing, generally with the addition of SBS type
rubber or atactic polypylenes (APP). Some are non-reinforced, while others are
reinforced with polyester, polyvinyl acetate, fiberglass, polypropylene or aluminum
foil.

MONITOR, SAW-TOOTH

A type of monitor characterized by sharp angled pitches and vertical sections,
usually arranged in rows much like teeth of a saw.

MONITOR

A large structure rising above the surrounding roof planes, designed to give light
and/or ventilation to the building interior.

MOPPING

A layer of hot bitumen mopped between plies of roofing felt.

MOPPING, FULL

The application of bitumen by mopping in such a manner that the surface being
mopped is entirely coated with a reasonably uniform coating.

MOPPING, SPOT

The procedure of applying hot bitumen in a random fashion of small daubs, as
compared to full mopping.

MOPPING, SPRINKLE

A special application of installing insulation to the decks. It is done by dipping a
roof mop into hot bitumen and sprinkling the material onto the deck.

MOPPING, STRIP

The application of bitumen in parallel bands.

MUD CRACKS

Cracks developing from the normal shrinkage of an emulsion coating when applied
too heavily.

NAILER

A piece of lumber secured to non-nailable decks and walls by bolts or other means,
which provides a suitable backing onto which roof components may be
mechanically fastened.

NON-DESTRUCTIVE

A phrase describing a method of examining the interior of a component whereby no
damage is done to the component itself.

NUCLEAR METER

A device used to detect moisture by measuring slowed, deflected neutrons.

OIL-CANNING

The term describing distortion of thin-gauge metal panels which are fastened in a
manner restricting normal thermal movement.

ORGANIC

A term designating any chemical compound which contains carbon and hydrogen.

OVERHANG

That part of the roof structure which extends horizontally beyond the vertical plane
of the exterior walls of a building.

OXIDIZE

To combine with oxygen in the air.

PARAPET WALL

A low wall around the perimeter of a roof deck.

PARGE COAT

A thin application of plaster for coating a wall.

PAVER STONES

Usually pre-cast concrete slabs used to create a traffic surface.

PENTHOUSE

A relatively small structure built above the plane of the roof.

PERLITE

An aggregate formed by heating and expanding siliceous volcanic glass.

PHASE CONSTRUCTION

In roofing the practice of applying the felt plies of the built-up roofing membrane in
two or more operations, separated by a delay of at least one day.

PHOTO-OXIDATION

Oxidation caused by rays of the sun.

PITCH

A term frequently used to designate coal tar pitch.

PITCH PAN OR POCKET

A bottomless metal box placed on the BURM around irregular projections. These
are subsequently filled with coal tar pitch or mastic to effect a weather tight seal.

PLY

A single course of roofing felts.

PLYWOOD

Wooden panels formed by gluing thin sheets of wood together, with the grain of
adjacent layers arranged at right angles.

POINTING

The process where joints between masonry units, brick, etc., are filled with mortar.

POLYMER

A substance consisting of large molecules which have been formed from smaller
molecules of similar make-up.

POLYURETHANE

Any of various polymers with a urethane base.

PONDING

A condition where water stands on a roof for prolonged periods due to poor
drainage and/or deflection of the deck.

POP RIVETS

Fasteners used to join pieces of metal that are installed by either compressed air
assisted or hand operated guns. Unique in that they are installed from one side of
the work.

POROSITY

The density of substance and its capacity to pass liquids.

POUR COAT

The top coating of bitumen on a built-up roof.

PRECAST

Concrete building components which are formed and cured at a factory and then
transported to a work site for erection.

PRIMER

A material of relatively thin consistency applied to a surface for the purpose of
creating a more secure bonding surface.

PROJECTION

Any object or equipment which pierces the roof membrane.

PROTECTION BOARD

Heavy asphalt impregnated boards which are laid over bituminous coatings to
protect against mechanical injury.

PURLINS

A horizontal structural member spanning between beams or trusses to support a
roof deck.

RAGGLE BLOCK

A specially designed masonry block having a slot or opening into which the top
edge of the roof flashing is inserted and anchored.

RAKE

The angle of slope of a roof rafter, or the inclined portion of a cornice.

REFLECTIVE

A term referring to a material that has a white or shiny metallic surface.

REGLET

A horizontal slot, formed or cut in a parapet or other masonry wall, into which the
top edge of counterflashing can be inserted and anchored.

RE-IMPREGNATE

To replace oils and bitumen in the components of the BURM which through
weathering and oxidation, have been lost.

ROOF

The assembly of interacting components designed to weatherproof and normally to
insulate a buildings surface, separated from adjacent assemblies by walls or
changes in elevation.

ROOF COATING

A bituminous material, either a cutback or an emulsion, to protect the surface of the
BURM but not necessarily to re-impregnate it.

ROOF DECK

That component in building construction, which forms a platform on which the
remainder of the BURM components are placed.

ROOF DRAIN

The termination or fitting at the roof of an interior drain or leader, for draining rain
water from nominally flat roofs.

ROOF SYSTEM

General term referring to the waterproof covering, roof insulation, vapor barrier, if
used and roof deck as an entity.

RUN

The horizontal distance between the eaves and the ridge of the roof, being half the
span for a symmetrical gable roof.

SADDLE

A ridge in the roof deck, whose top divides two sloping parts of the roof so that
water will be diverted to the roof drains.

SAW TOOTH ROOF

Where reviewed from the end, such a roof serrated or tooth profile similar to the
teeth of a saw.

SCRIM

A woven or mat-type fabric that is used as a membrane sandwich between other
material to provide reinforcement and stretch resistance.

SCUPPER

An outlet in the wall of a building or a parapet wall for drainage of water from a flat
roof.

SELF-HEALING

A term used in reference to a material which melts with the heat from the sun's rays,
and seals over cracks that were earlier formed from other causes.

SELF-LEVELING

A viscous material that is applied by pouring. In its uncured state, it spreads out
evenly.

SELVAGE

The unsurfaced strip along a sheet of roll roofing which forms the under portion at
the lap in the application of the roof covering.

SHED ROOF

A roof having only one slope or pitch, with only one set of rafters which fall from a
higher to a lower wall.

SHEATHING

The boards of sheet type material, plywood or asphalt saturated sheets, nailed to
studding or roofing rafters as the base for application of the roof covering.

SHINGLE-FASHION

The pattern formed by laying parallel felt rolls with lapped joints so that one
longitudinal edge overlaps the longitudinal edge on the adjacent felts. Shingle
fashion application begin at the low point on a roof so that one ply drains water to
a lower one and so on to a drain or to the roof edge.

SHINGLES

Small units of material which are laid in a series of overlapping rows as a roof
covering on pitched roofs.

SIGN ANCHOR

A component usually formed with steel angles which penetrates the BUR and is
fastened to the deck.

SINGLE PLY

A descriptive term signifying a roof membrane composed of only one layer of material
such as EPDM, Hypalon or PVC.

SINGLE TEE

The name given to a type of precast concrete deck which has one stiffening rib
integrally cast into slab.

SITE

The physical grouping of a number of roofs or buildings at a geographical location.

SKY DOME

A type of skylite exhibiting a characteristic translucent plastic domed top.

SKYLIGHT

A structure on a roof that is designed to admit light and is somewhat above the
plane of the roof surface.

SLAG

A by-product of smelting ore such as iron, lead or copper.

SLATE

A dark gray stratified stone cut relatively thin and installed on pitched roofs in a
shingle like fashion.

SLIPPAGE

It is the sliding, lateral movement between adjacent to plies of felt along the plane
of the bitumen film separating them, which results in a randomly wrinkled
appearance.

SLOPE

Incline or pitch of roof surface.

SOFFIT

The underside of a part or member of a building extending out from the plane of the
building walls.

SOFTENING POINT

The temperature at which a substance changes from a hard material to a softer and
more viscous material.

SPALLING

The chipping or flaking of concrete, bricks, or other masonry where improper
drainage or venting and freeze/thaw cycling exists.

SPAN

The horizontal distance between supporting structures such as beams, trusses or
columns.

SPECIFICATION

Detailed written instructions which, when clear and concise, explain each phase of work
to be done.

SPLITTING

The formation of long cracks completely through a roof membrane. Splits are
frequently associated with lack of allowance for expansion stresses. They can also
be a result of deck deflection or change in deck direction.

SQUARE

A term used by the roof industry to indicate an amount of roof area equal to 100 square feet.

SPUD

The removal of gravel or heavy accumulations of bitumen from roof membranes by means
of chipping or scrapeing

STACK

A vertical pipe projecting through a BUR that carries off smoke or gases.

STANDING SEAM

A type of joint often used on metal roofs.

STARTER STRIPS

In the construction of the BUR the narrow strips of roofing felts, cut from standard
width rolls, that are applied at the beginning point so as to assure uniform
configuration of the specified number of plies.

STATIC LOAD

In roofing the total amount of permanent non moving weight that is applied to given
surface areas.

SUBSTRATE

A part or substance which lies below and supports another.

SUMP

A reservoir sometimes forming part of a roof drain. A depression in the roof deck
of a building at a roof and delivery it to the drain.

TEAR OFF

A term used to describe the complete removal of the built up roof membrane and
insulation down to and exposing the roof deck.

THERMAL MOVEMENT

The measured amount of dimensional change, a material exhibits as it is warmed
or cooled.

THERMAL SHOCK

The stress built up by sudden and appreciable changes in temperature.

THERMOPLASTIC MATERIAL

Solid material which is softened by increasing temperatures and hardened by
decreasing temperatures.

TIE-IN

A term used to describe the joining of a new roof with the old.

TILT-UP WALL

Cast concrete units which are preformed which, when cured, are tilted
to their vertical position and secured by mechanical fasteners to prior erected
structural steel. May be pre-cast.

TOP MOPPING

The finished mopping of hot bitumen on a built-up roof.

TORCHING

Applying direct flame to a membrane for the purpose of melting, heating or adhering.

TRUSS

A major supporting structure usually timber for roof decks.

TUCK POINTING

The re-grouting of defective mortar joints in a masonry or brick wall.

ULTRAVIOLET

The invisible rays of the spectrum which are at its violet end. Sometimes
abbreviated U.V.

VALLEY

A term applied to a depressed angle formed by the meeting of two inclined slopes
of a roof.

VAPOR

The gaseous form of any substance.

VAPOR RETARDER (BARRIER)

A membrane which is placed between the insulation and the roof deck to retard
water vapor in the building from entering the insulation and condensing into liquid
water.

VEINING

The characteristic lines or "stretch marks" which develop during the aging process
of soft bitumens.

VENT PIPE

A vertical pipe of relatively small dimensions which protrudes through a roof to
provide for the ventilation of gasses.

VENTILATOR

Device installed on the roof for the purpose of ventilating the interior of the building.

VENTING

1. The process of installing roof vents in a roof assembly to relieve vapor
pressure.
2. The process of water in the insulation course of the roof assembly
evaporating and exiting via the roof vents.

VERMICULITE

An aggregate somewhat similar to perlite that is used as an aggregate in lightweight
roof decks and deck fills. It is formed from mica, a hydrous silicate.

VERTICAL APPLICATION

Roll roofing laid parallel to the slope of a roof.

VISCOSITY

The internal frictional resistance offered by a fluid to change of shape or to the
relative motion or flow of its parts.

WALKWAYS

Designated areas for foot traffic on roofs.

WATER STOP

A device designed to protect the exposed edge of a partially installed BURM from
water entrance.

WATERPROOFING

The process where a building component is made totally resistant to the passage
of water and/or water vapor.

WATER VAPOR

Moisture existing as a gas in air.

WEEP HOLE

A hole which allows for drainage of entrapped water from masonry structures.

WELD

The joining of components together by fusing. In thermoplastics, refers to bonding
together of the membrane using heat or solvents.

WIND UPLIFT

The upward force exerted by wind traveling across a roof.

WRINKLE

A raised pattern of ridges running in a random fashion in a BUR.

ZONOLITE

A lightweight, insulating concrete composed of portland cement, water, and
vermiculite aggregate.