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ASTM - American Society for Testing and Measurement
is a not-for-profit organizaiton which rovides a forum for producers and
consumers to meet on common ground and to write standards for materials,
products, systems, and services.
Aggregate - 1. crushed stone, crushed slag or water worn gravel
used for surfacing a built-up roof. 2. any granular mineral material.
Alligatoring - the cracking of the surfacing bitumen on a built-up
roof, producing a pattern of cracks similar to an alligator's hide; the
cracks may or may not extend through the surfacing bitumen.
Application Rate - the quantity (mass, volume, or thickness) of
material applied per unit area.
Area Divider - a raised, double wood member attached to a properly
flashed wood base plate that is anchored to the roof deck. It is used
to relieve thermal stresses in a roof system where no expansion joints
have been provided.
Asbestos - a group of natural, fibrous, impure silicate materials.
Asphalt - a dark brown to black cementitious material in which
the predominating constituents are bitumens, which occur in nature or
are obtained in petroleum processing. Dead-Level Asphalt: a roofing
asphalt conforming to the requirements of ASTM Specification D 312, Type
I. Flat Asphalt: a roofing asphalt conforming to the requirements
of ASTM Specification D 312, Type II. Steep Asphalt: a roofing
asphalt conforming to the requirements of ASTM Specification D 312, Type
III. Special Steep Asphalt: a roofing asphalt conforming to the
requirements of ASTM Specification D 312, Type IV.
Asphalt, Air Blown - an asphalt produced by blowing air through
molten asphalt at an elevated temperature to raise its softening point
and modify other properties.
Asphalt Felt - an asphalt-saturated felt or an asphalt coated
felt.
Asphalt Mastic - a misture of asphaltic material and graded mineral
aggregate that can be poured when heated but requires mechanical manipulation
to apply when cool.
Asphaltene - a high molecular weight hydrocarbon fraction precipitated
from asphalt by a designated paraffinic naptha solvent at a specified
temperature and solvent-asphalt ratio. NOTE: The asphaltene fraction should
be indentified by the temperature and solvent asphalt ratio used.
Backnailing - the practice of blink-nailing roofing
felts to a substrate in addition to hot mopping to prevent slippage.
Base Ply - the lowermost ply of roofing material in a roof assembly.
Base Sheet - a saturated or coated felt placed as the first ply
in some multi-ply built-up roof membranes.
Bitumens - 1. a class of amorphous, black or dark colored, (solid,
semi-solid, or viscous) cementitious substances, natural or manufactured,
composed principally of high molcular weight hydrocarbons, soluble in
carbon disulfide, and found in asphalts, tars, pitches, and asphaltites;
2. a generic term used to denote any material composed principally of
bitumen.
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).
Blind Nailing - the practice of nailing the back portion of a
roofing ply in a manner that the fasterners are not exposed to the weather
in the finished product.
Blister - an enclosed pocket of air mixed with water or solvent
vapor, trapped between impermeable layers of felt, or between the felt
and substrate.
Blocking - 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.
Bond - the adhesive and cohesive forces holding two roofing components
in intimate contact.
Breaking Strength - the amount of tension required to cause material
or a system to give way or collapse. It is calculated by measuring the
amount of force required to fracture a uniform sized sample.
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.
British Thermal Unit (BTU) - the heat energy required to raise
the temperature of 1 pound of water 1 degree fahrenheit.
Built-Up Roof Membranes - 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
surface with mineral aggregate, bituminous materials, or a granule-surfaced
roofing sheet. (Abbreviation: BUR)
Cant Strip - a beveled strip used under flashing
to modify the angle at the point where the roofing or waterproofing membrane
meets any vertical element.
Capillarity - the action by which the surface of a liquid (where
it is in contact with a solid) is elevated or depressed, depending upon
the relative attraction of the molecules of the liquid for each other
and for those of the solid.
Cap Sheet - a granule-surfaced coated sheet used as the top ply
of a built-up roof membrane or flashing.
Caulk - a composition of vehicle and pigment, used at ambient
temperatures for filling joints, that remains plastic for an extended
time after application.
Coal Tar - a dark brown to black, semi-solid hydrocarbon obtained
as residue from the partial evaporation or distillation of coal.
Coal-Tar Pitch - a coal tar used as the waterproofing agent in
dead-level or low slope built-up roof membrane, conforming to ASTM Specification
D 450, Type I. Coal-Tar Waterproofing Pitch: a coal tar used as
the damproofing or waterproofing agent in below-grade structures, conforming
to ASTM D 450, Type II. Coal-Tar Bitumen: a coal tar used as the
waterproofing agent in dead-level or low slope built-up roof membrane,
conforming to ASTM D 450, Type III.
Coal-Tar Felts - a felt that has been saturated with refined coal
tar.
Coated Sheet Felt - 1. an asphalt felt that has been coated on
both sides with harder, more viscous asphalt; 2. a glass fiber felt that
has been simultaneously impregnated and coated with asphalt on both sides.
Cold-Processing Roofing - a continous, semi-flexible roof membrane,
consisting of plies of felts, mats, or fabrics that are laminated on a
roof with alternate layers of cold-applied roof cement and surfaced with
a cold-applied coating.
Condensation - the conversion of water vapor or other gas to liquid
as the temperature drops or the atmospheric pressure rises.
Coping - the covering piece on top of a wall exposed to the weather,
usually sloped to shed water.
Counterflashing - formed metal or elastomeric sheeting secured
on or into a wall, curb, pipe, rooftop, unit or other surface, to cover
and protect the upper edge of a base flashing and its associated fasteners.
Course - 1. the term used for each application of material that
forms the waterproofing system or the flashing; 2. one layer of a series
of material applied to a surface (i.e., a five-course wall flashing is
composed of three applications of mastic with one ply of felt sandwiched
between each layer of mastic.)
Coverage - the surface area continuously covered by a specific
quantity of particular roofing material.
Crack - a separation or fracture occurring in a roof membrane or
roof deck, generally caused by thermal induced stress or substrate movement.
Creep - the permanent deformation of a roofing material or roof
system caused by the movement of the roof membrane that results from continuous
thermal stress or loading.
Cricket - a relatively small, elevated area of a roof constructed
to divert water.
Cutback - solvent-thinned bitumen used in cold process roofing
adhesives, flashing cements and roof coatings.
Cutoff - a detail designed to prevent lateral water movement into
the insulation where the membrane terminates at the end of a day's work,
or used to isolate sections of the roofing system. It is usually removed
before the continuation of the work.
Damproofing - treatment of a surface or structure
to resisit the passage of water in the absence of hydrostatic pressure.
Dead Level - absolutely horizontal, or zero slope.
Dead Loads - non-moving rooftop loads, such as mechanical equipment,
air conditioning units, and the roof deck itself.
Deck - the structural surface to which the roofing or waterproofing
system is applied.
Delamination - separation of the plies in a roof membrane system
or separation of laminated layers of insulation.
Dew Point - the temperature at which water vapor starts to condense
in cooling air at the existing atmospheric pressure and vapor content.
Double-Pour - the process of applying two layers of aggregate and
bitumen to a built-up roof.
Drain - a device that allows for the flow of water from a roof
area.
Edge Sheets - felt strips that are cut to widths
narrower than the standard width of the full felt rool, used to start
the felt shingling pattern at a roof edge.
Edge Stripping - application of felt strips cut to narrower widths
than the normal felt roll width to cover a joint between flashing and
built-up roofing.
Edge Venting - the practice of providing regularly spaced protected
opening along a roof perimeter to relieve moisture vapor pressure.
Elastomeric - a rubber like synthetic polymer that will strengthen
when pulled and will return quickly to its original shape when released.
Embedment - 1. the process of pressing a felt, aggregate, fabric,
mat, or panel uniformly and completely into hot bitumen or adhesive; 2.
the process of pressing granules into coating in the manufacture of factory
prepared roofing.
Emulsion - the homogeneous dispersion of an organic material and
water achieved by using a chemical or clay emulsifying agent.
Envelope - a continuous membrane edge seal 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.
Equiviscous Temperature (EVT) - the temperature at which the viscosity
if 75 centipoise for asphalt and 25 centipoise for coal tar products;
the recommended temperature for mopping asphalt plus or minus 25 F at
the time of application.
Expansion Joint - a structural separation between two building
elements that allows free movement between the elements without damage
to the roofing or waterproofing system.
Exposure - 1. the traverse dimension of a roofing element not overlapped
by an adjacent element in any roof system. The exposure of any ply in
a membrane may be computed by dividing the felt width minus 2 inches by
the number of shingled plies.
Fabric - a woven cloth of organic or inorganic
filaments, threads, or yarns.
Factory Mutual (FM) - an organization that classifies roof assemblies
for their fire characteristics and wind uplift resistance for insurance
companies in the United States.
Factory Square - 108 square feet of roofing material.
Felt - a flexible sheet manufactured by the interlocking of fibers
through a combination of mechancial work, moisture, and heat. Felts are
manufactured principally from vegetable fibers (organic felts), or glass
fibers (glass fiber felts); other fibers may be present in each type.
Felt Layer - a machine used for applying bitumen and built-up
roofing plys.
Fine Mineral Surfacing - water-insoluble, inorganic material,
more than 50 percent of which passes the No.35 sieve, used on the surface
of roofing.
Fishmouth - 1. a half-cylindrical or half-conical opening formed
by an edge wrinkle; 2. in shingles, a half-conical opening formed at a
cut edge.
Flashing - the system used to seal membrane edges at walls, expansion
joints, drains, gravel stops, and other places where the membrane is interrupted
or terminated. Base flashing covers the edge of the membrane. Cap flashing
or counterflashing shields the upper edges of the base flashing.
Flashing Cement - a trowelable mixture of cutback bitumen and
mineral stabilizers, including organic or other inorganic fibers.
Flood Coat - the top layer of bitumen into which the aggregate
is embedded on an aggregate-surfaced built-up roof.
Fluid Applied - an elastomeric material, fluid at ambient temperature,
that dries or cures after application to form a continuous membrane. Such
systems normally do not incorporate reinforcement.
Glass Felt - glass fibers bonded into a sheet
with resin and suitable for impregnation in the manufacture of bituminous
waterproofing materials, roof membranes, and shingles.
Glass Mat - a mat composed of glass fibers with or without a binder.
Glaze Coat - 1. the top layer of asphalt in a smooth sufaced built-up
roof assembly; 2. a thin protective coating of bitumen applied to the
lower plies or top ply of a built-up roof membrane when application of
additional felts or the flood coat and aggregate surfacing are delayed.
Gravel - course, granular aggregate, with pieces larger than sand
grains, resulting from the natural erosion of rock.
Gravel Stop - a flanged device, frequently metallic, designed
to provide a continuous finished edge for roofing material and to prevent
loose aggregate from washing off the roof.
Headlap - the minimum distance, measured at 90
degrees to the eaves along the face of a shingle or felt, from the upper
edge of the shingle or felt to the nearest exposed surface.
Holiday - an area where a liquid-applied material is missing.
Hot - "Hot Stuff" or "Hot", the roofer's term
for hot bitumen.
Ice Dam - a mass of ice formed at the transition
from a warm to cold roof surface, frequently formed by refreezing meltwater
at the overhang of a steep roof, causing ice and water to back up under
roofing materials.
Incline - the slope of a roof expressed either in percent or in
the number of vertical units of rise per horizontal unit of run.
Inorganic - being or composed of matter other than hydrocarbons
and ther derivatives, or matter that is not of of plant or animal origin.
Job-Average Basis - a technique for determining
the average dimensions or quantities of material, by analysis of roof
test cust. The tecnique requires a minimum of three test cust per rof
area, plus one cut for each additional 10,000 square feet of roof area.
Job-average basis is computed by dividing the sum of all measurements
taken by the number of measurements taken. The results would describe
the job-average for the quantity or dimension.
Knot - an imperfection or non-homogeneity in
materials used in fabric construction, the presence of which causes surface
irregularities.
Live Loads - moving roof installation equipment,
wind, snow, ice, or rain.
Membrane - a flexible or semi-flexible roof covering
or waterproofing layer, whose primary function is the exclusion of water.
Metal Flashing (See Flashing) - Metal flashing is frequently used
as through-wal flashing, cap flashing, counterflashing, or gravel stops.
Mineral Granules - opaque, natural, or synthetically colored aggregate
commonly used to surface cap sheets, granule-surfaced sheets, and roofing
shingles.
Mineral Stabilizer - a fine, water-insoluble inorganic material,
used in a mixture with solid or semi-solid bituminous materials.
Mineral-Surfaced Roofing - built-up roofing materials whose top
ply consists of a granule-surfaced sheet.
Mineral-Surfaced Sheet - a felt that is coated on one or both sides
with asphalt and surfaced with mineral granules.
Modified Bitumen - are composite sheets consisting of a copolymer
modified bitumen often reinforced and sometimes surfaced with various
types of films, foils, and mats.
Mop-and-Flop - an application procedure in which roofing elements
(insulation boards, felt plies, cap sheets, etc.) are initially placed
upside down adjacent to their ultimate location, are coated with adhesive,
and are the turned over and applied to the substrate.
Mopping - the application of hot bitumen with a mop or mechanical
applicator to the substrate or to the felts of a built-up roof membrane.
Solid Mopping - a continuous mopping of a surface, leaving
no unmopped areas. Spot Mopping - a mopping pattern in which
hot bitumen is applied in roughly circular areas, leaving a grid of unmopped
perpendicular bands on the roof. Sprinkle Mopping - a random
pattern in which heated bitumen beads are strewn into the substrate with
a brush or mop. Strip Mopping - a mopping pattern in which
hot bitumen is applied in parallel bands.
Neoprene - a synthetic rubber (polychloroprene)
used in liquid-applied and sheet applied elastomeric roof membrane or
flashings.
Ninety-Pound - a prepared organic felt roll roofing with a granule
surfaced exposure that has a mass of approximately 90 pounds per 108 square
feet.
Organic - being or composed of hydrocarbons or
their derivatives, or matter of plant or animal origin.
Parapet Wall - that part of any wall entirely
above the roof.
Perlite - an aggregate used in lightweight insulating concrete
and in preformed perlitic insulation board, formed by heating and expanding
siliceous volcanic glass.
Phased Application - the installation of a roof system or waterproofing
system during two or more separate time intervals.
Picture Framing - a rectangular pattern of ridges in a roof membrane
over insulation or deck joints.
Pitch Pocket - a flange, open-bottomed, metal container placed
around columns or other roof penetrations that is filled with hot bitumen
or flashing cement to seal a projection.
Ply - a layer of felt in a built-up roof membrane system. A four-ply
membrane system has four plies of felt.
Ponding - a roof surface that is incompletely drained.
Positive Drainage - the drainage condition in which consideration
has been made for all loading deflections of the deck, and additional
roof slope has been provided to ensure drainage of the roof area within
48 hours of rainfall.
Primer - a thin, liquid bitumen applied to a surface to improve
the adhesion of subsequent applications of bitumen.
Rake - the slope edge of a roof at the first
or last rafter.
Re-covering - the process of covering an existing roofing system
with a new roofing system.
Re-entrant Corner - an inside corner of a surface, producing stress
concentrations in the roofing or waterproofing membrane.
Reglet - a groove in a wall or other surface adjoining a roof
surface for use in the attachment of counterflashing.
Reinforced Membrane - a roofing or waterproofing membrane reinforced
with felts, mats, fabrics, or chopped fibers.
Relative Humidity - the ratio of the weight of moisture in a given
volume of air-vapor mixture to the saturated (maximum) weight of water
vapor at the same temperature, expressed as a percentage. For example,
if the weight of the moist air is 1 pound and if the air could hold 2
pounds of water vapor at a given temperature, the relative humidity is
50 percent.
Replacement - the practice of removing an existing roof system
and replacing it with a new roofing system.
Re-roofing - the process of re-covering or replacing an existing
roofing system.
Ridging - an upward, tenting displacement of a roof membrane frequently
occurring over insulation joints, deck joints and base sheet edges.
Roll Roofing - smooth-surfaced or mineral-surfaced coated felts.
Roof Assembly - an assembly of interacting roof components (including
the roof deck) designed to weatherproof and, normally, to insulate a building's
top surface.
Saddle - a small structure that helps channel
surface water to drains, frequently located in a valley, and often constructed
like a small hip roof or like a pyramid with a diamond shape base.
Saturated Felt - a felt that has been saturated with low softening
point bitumen.
Screen - an apparatus with circular apertures for separating sizes
of materials.
Scuttle - a hatch that provides access to the roof from the interior
of the building.
Seal - 1. a narrow closure strip made of bituminous materials;
2. to secure a roof from the entry of moisture.
Sealant - a mixture of polymers, fillers, and pigments used to
fill and seal joints where moderate movement is expected; it cures to
a resilient solid.
Selvage - an edge or edging that differs from the main part of
a fabric or a granule-surfaced roll roofing material.
Selvage Joint - a lapped joint designed for mineral-surfaced cap
sheets. The mineral surfacing is omitted over a small portion of the longitudinal
edge of the sheet below in order to obtain better adhesion of the lapped
cap sheet surface with the bituminous adhesive.
Shingle - 1. a small unit of prepared roofing material designed
for installation with similar units in overlapping rows on inclines normally
exceeding 25 percent; 2. to cover with shingles; 3. to apply any sheet
material in overlapping rows like shingles.
Shingling - 1. the procedure of laying parallel felts so that one
longitudinal edge of each felt overlaps and the other longitudinal edge
underlaps, an adjacent felt. Normally felts are shingled on a slope so
that the water flows over rather than against each lap; 2. the application
of shingles to a sloped roof.
Slag - a hard, air-cooled aggregate that is left as a residue from
blast furnace, used as a surfacing aggregate.
Slippage - relative lateral movement of adjacent components of
a built-up membrane. It occurs mainly in roofing membranes on a slope,
sometime exposing the lower plies or even the base sheet to the weather.
Smooth-Surfaced Roof - a built-up roof membrane surfaced with
a layer of hot-mopped asphalt, cold-applied asphalt clay emulsion, cold-applied
asphalt cutback, or sometimes with an unmopped inorganic felt.
Softening Point - the temperature at which bitumen becomes soft
enough to flow, as determined by ASTM D 36-86.
Softening Point Drift - a change in the softening point of bitumen
during storage or application.
Split - a membrane tear resulting from substrate or membrane
stress.
Spudding - the process of removing the roofing aggregate and most
of the bituminous top coating by scraping and chipping.
Square - the term used to describe 100 square feet of roof area.
Stack Vent - a vertical outlet in a built-up roof system desinged
to relieve the pressure exerted by moisture vapor between the roof membrane
and the vapor retarder or deck.
Stripping or Strip-Flashing - 1. the technique of sealing a joint
between metal and the built-up roof membrane with one or two plies of
felt or fabric and hot-applied or cold-applied bitumen; 2. the technique
of taping joints between insulation boards or deck panels.
Substrate - the surface upon which the roofing or waterproofing
membrane is applied.
Sump - an intentional depression around a drain.
Superimposed Loads - loads that are added to existing loads. For
example, a large stack of insulation boards placed on top of a structural
steel deck.
Tapered Edge Strip - a tapered insulation strip
used to elevate the roof at the perimeter and at curbs that extend through
a roof and to provide a gradual transition from one layer of insulation
to another.
Tar - a brown or black bituminous material, liquid, or semi-solid
in consistency, in which the predominating constituents are bitumens obtained
as condensates in the processing of coal, petroleum, oil-shale, wood,
or other organic materials.
Test Cut - a sample of the roof membrane that is cut from a roof
membrane to determine the weight of the average interply bitumen moppings
and to diagnose the condition of the existing membrane.
Thermal Conductance (C) - a unit of heat flow that is used for
specific thicknesses of material or for materials of combination construction,
such as laminated insulation.
Thermal Conductivity (k) - the heat energy that will be transmitted
by conduction through 1 square foot of 1 inch thick homogeneous material
in one hour when there is a difference of 1 degree Fahrenheit perpendicularly
across the two surfaces of the material.
Thermal Insulation - a material applied to reduce the flow of
heat.
Thermal Resistance (R) - an index of a material's resistance to
heat flow; it is the reciprocal of thermal conductivity (k) or thermal
conductance (C).
Thermal Shock - the stress-producing phonomenon resulting from
suddent termperature changes in a roof membrane when, for example, a rain
shower follows brilliant sunshine.
Through-Wall Flashing - a water-resistant membrane or material
assembly extending through a wall and its cavaties, positioned to direct
water entering the top of the wall to the exterior.
Tuck Pointing - 1. troweling mortar into a joint after masonry
units are laid; 2. final treatment of joints in cut stonework. Mortar
or a putty-like filler is forced into the joint after the stone is set.
Underwriters Laboratory and Warnock Hersey -
Organizations that test and classify consumer products such as roof assemblies
to methods defined by objective forums like ASTM.
Vapor Migration - the movement of water vapor
from a region of high vapor pressure to a region of lower vapor pressure.
Vapor Retarder - a material designed to restrict the passage of
water vapor through a roof or wall.
Vent - an opening designed to convey water vapor or other gas from
inside a building or a building component to the atmosphere, thereby relieving
vapor pressure.
Vermiculite - an aggregate used in lightweight insulating concrete,
formed by the heating and consequent expansion of a micaceous mineral.
Waterproofing - treatment of a surface or structure
to prevent the passage of water under hydrostatic pressure.
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