16. Glossary

(1) Crushed stone, crushed slag, or water-worn gravel used for surfacing a built-up roof; (2) Any granular mineral material.
Apron Flashing:
Copper flashing that covers the intersection at a sloping roof with a vertical wall, such as the lower side of a chimney.
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 the stresses of thermal expansion and contraction in a roof system where no expansion joints have been provided.
A dark brown to black cementitious material in which the predominating constituents are bitumens, which occur in nature or are obtained in petroleum processing.
Base Flashing:
The flashing at the joint between a roofing surface and a vertical surface.
Base Ply:
The first ply of roofing material in a roof membrane assembly.
Base Sheet:
A saturated or coated felt placed as the first ply in built-up roof membranes.
The generic term for an amorphous, semi-solid mixture of complex hydrocarbons derived from coal-tar pitch or asphalt.
Bituminous Coating:
A paint with a bitumen base, used in copper construction primarily to prevent direct contact of dissimilar metals.
Blind Nailing:
Nailing in such a way that the nail heads are not visible on the finished work.
Blind Rivet:
Riveting in such a way that the rivets are not visible on the finished work.
A copper alloy having zinc as its principal alloying element. For exact definition, see UNS Standard Designations.
Traditionally, a copper alloy having tin as its principal alloying element. For exact definition, see UNS Standard Designations.
Building Paper:
A heavy durable paper such as rosin sized paper, used in construction typically to improve thermal insulation and weather protection, and to act as a vapor barrier. In copper applications it is often used between the copper and underlayment to prevent bonding that could restrict copper movement. Same as Roofing Paper.
Built-Up Roof Membrane:
A continuous, semi-flexible roof membrane assembly, consisting of piles 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.
Built-up roofing.
Cant Strip:
(1) A bevelled strip of wood or other material that fits into the angle formed by the intersection of a horizontal surface and a vertical surface. The 45° slope of the exposed surface of the cant strip provides a gradual angular transition from the horizontal surface to the vertical surface to prevent the cracking of roofing applied over it.
(2) A wood board or a formed copper strip which is laid so as to cant the first row of shingles on a roof.
Cap Flashing:
Same as Counterflashing.
A resilient mastic compound often having a silicone or rubber base, used to fill cracks and joints, that remains plastic for an extended period of time.
A small strip of copper, usually 16 ounce material, used to fasten sheet copper components, such as roofing or flashing to the supporting understructure. Expansion cleats allow the components to move to account for thermal variations, fixed cleats do not.
Concrete masonry unit or concrete block.
Collar Joint:
The vertical joint between masonry wythes.
Composition Flashing:
Base flashing that is constructed by extending the plies of a built-up roof.
The conversion of water vapor or other gas to liquid as the temperature drops or the atmospheric pressure rises.
The covering piece placed on top of a wall that is exposed to the weather. It is usually sloped to shed water.
Copper Cold Rolled:
A strong yet still fairly malleable type of copper that is very well suited to building construction. It has a yield strength of 26,000-28,000 psi.
Copper Soft Temper:
A type of extremely malleable copper used only for intricate ornamental applications. It is not recommended for general use in construction.
Formed sheet copper 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.
(1) The term used for each application of material that forms the waterproofing system or the flashing;
(2) a layer of masonry units running horizontally in a wall bonded with mortar.
A small saddle-shaped projection on a sloped roof used to divert water around an obstacle such as a chimney.
Treatment of a surface or structure to resist the passage of water in the absence of hydrostatic pressure.
The structural surface to which the roofing or waterproofing system is applied
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.
Edge Sheets:
Felt strips that are cut to widths narrower than the standard width of the full felt roll. They are used to start the felt-shingling pattern at a roof edge.
Edge Strip:
A long narrow copper flashing used to protect the edge of a roof or other surface.
Erosion Corrosion:
Where concentrated amounts of water hit a copper roof causing erosion of copper material.
Expansion Joint:
A structural separation between two building elements designed to minimize the effect of the stresses and movements of a building's components and to prevent these stresses from splitting or ridging the roof membrane.
The transverse dimension of a roofing element not overlapped by an adjacent element in any roof system.
Factory Square:
108 square feet (10 square meters) of roofing material. See Square.
A fabric manufactured from vegetable fibers (organic felts), or glass fibers (glass fiber felts). The manufacturing process involves mechanically interlocking the fibers of the particular felt material in the presence of moisture and heat.
Sheet copper material placed in construction, such as in mortar joints, to prevent water penetration and/or to divert water which has already penetrated.
Full Collar Joint:
A vertical joint between masonry wythes that has been grouted solid.
The thickness of copper material. Can be designated by a number, or more commonly for copper, by the weight of material per square foot, in ounces.
The width of sheet copper material (in the flat) used to form a gutter.
Coarse, granular aggregate, containing pieces approximately 5/8 inch to 1/2 inch in size and suitable for use in aggregate surfacing on built-up roofs.
Gravel Stop:
A flanged copper device, designed to provide a continuous finished edge for roofing materials and to prevent loose aggregate from washing off the roof.
The minimum distance, measured at 90 degrees to the eaves along the face of a shingle or felt, from the upper edge of a shingle or felt to the nearest exposed surface.
Hemmed Edge:
The edge of sheet copper which has been folded under completely. All exposed sheet copper edges should have 1/2" nominal hem.
"High Yield" Copper:
A specially developed sheet copper defined in ASTM B370 as cold rolled high yield temper copper. It's yield strength is 31,000-33,000 psi.
Hold Down:
A method of fastening sheet copper that involves the use of a brass screw with a large copper or brass washer. The screw is tightened sufficiently to keep the metal flat, but not restrict its lateral movement. The entire assembly is usually covered with a copper cap, fully soldered to provide watertightness.
Line Corrosion:
The linear degradation and pitting of copper placed under a drip edge. This is often the result of acidic moisture deposited on an inert (non-copper) which directs water to a valley or gutter. Under severe conditions, this concentration of acidic moisture can corrode copper flashing and gutters before they can form a copper sulfate patina. Protection from line corrosion is achieved by raising the shingle edges slightly by means of a cant, in order to break capillarity, or by providing a replaceable reinforcing strip between the shingle line and the copper valley flashing.
A flexible or semi-flexible roof covering or waterproofing layer, whose primary function is the exclusion of water.
Muntz Metal:
A copper-zinc metal having 60% copper and 40% zinc.
A wood strip, attached to a surface, used as a base for nailing or attaching other material.
On center.
The naturally protective coating that results from the mild corrosive attack of airborne sulfur compounds. The sulfate patina significantly increases the durability and service life of copper roofing and flashing.
Pea Gravel:
Small diameter (1/4 to 3/8 inch) natural gravel, used in conjunction with through-wall flashing to help prevent debris from blocking the flow of moisture.
The end of a hammer opposite the flat hammering face. It may be cone-shaped, rounded, or sharply pointed: it is used to create a textured finish on copper and other materials.
The tangent of the angle between the roof surface and the horizontal. It is measured in inches per foot. For copper construction pitch is ranked as follows:
Low Pitch: 3 to 6 inches per foot.
Steep Pitch: 6 inches and higher per foot.
A layer of felt in a built-up roof membrane system. A four-ply membrane system has four plies of felt.
The sloped edge of a roof at first or last rafter.
Raked Joint:
A mortar joint which, during construction or at a later date, has been tooled to provide a deep recess. This recess is used as a reglet into which copper cap or counterflashing may be inserted.
Same as Reglet.
A copper flashing, built into a wall, that locks into the upper edge of base or counterflashing.
A groove in a wall or other surface adjoining a roof surface for use in the attachment of counterflashing. Same as Raggle.
An upward, "tenting" displacement of a roof membrane, frequently occurring over insulation joints, deck joints and base sheet edges.
Roofing Paper:
Same as Building Paper.
Roof System:
A system of interacting roof components (NOT including the roof deck), designed to weather-proof and, normally, to insulate a building's top surface.
Rosin Sized Paper:
A heavy building paper impregnated with rosin.
Saturated Felt:
A felt that has been partially saturated with low softening point bitumen.
An opening in a wall or parapet that allows water to drain from a roof.
A mixture of polymers, fillers, and pigments used to fill and seal joints. Used to prevent the penetration of water or air.
Mechanical seamers are available for both standing seam and batten seam roof systems. They create precise, uniform seams without the hammer marks typical of manual seaming techniques.
(1) A small unit of prepared roofing material designed to be installed with similar units in overlapping rows on inclines normally exceeding 25%;
(2) to cover with shingles;
(3) to apply any sheet material in overlapping rows like shingles.
Slip Sheet:
A lightweight rosin sized paper inserted between sheet copper and underlayment to prevent bonding. See Building Paper.
See Pitch.
The term used to describe 100 square feet of roof area. See Factory Square.
Sq. Ft.:
Square feet.
Stack Vent:
The extension (to the open air) of a soil or waste stack through the roof membrane.
Step Flashing:
Discontinuous flashing in masonry walls which follows the elevation of a sloped roof, and is therefore inserted into successive courses, forming steps.
The surface upon which the roofing or waterproofing membrane is applied (i.e., the structural deck or insulation).
Tapered Edge Strip:
A tapered strip used to (1) elevate the roof at the perimeter and at curbs that extend through the roof; or (2) provide a gradual transition from one layer of insulation to another.
A water-resistant membrane of sheet copper which extends through a wall and its cavities, positioned to divert moisture to the exterior.
A material, such as saturated No. 15 felt, placed on the roof deck to improve weather resistance.
Unless otherwise noted.
Treatment of a surface or structure to prevent the passage of water under hydrostatic pressure.
A small opening in a wall, through which accumulated moisture may drain to the exterior.