This glossary is provided to offer a better understanding of exterior restoration & repair terminology.
Aggregate–
In two sizes, fine or coarse. Crushed stone, gravel, mineral or slag granules.
Unlike ballast, which is smooth (river rock).
AIA – American
Institute of Architects.
Alligatoring –
Cracks which are visible on the surfaces of smooth membrane roof coatings
or spots where aggregate is missing from an aggregate-surface roof. This occurs
from the roofing membrane hardening from the air and the sun.
Ambient Temperature
– The temperature of surrounding air.
Appurtenance –
Architectural ornament or structure that protrudes from the building's exterior.
Apron Flashing
– Sheet metal flashing used at the junction of a steep roof and a veridical
wall abutting the roof.
ARMA – Asphalt
Roofing Manufactures Association.
ASCE – American
Society of Civil Engineers.
Asphalt –
Waterproofing agent, highly viscous bitumen produced from petroleum, brown
or black.
ASTM – American
Society for Testing and Materials.
Backup –Wall
behind the exterior wall facing, which can consist of several layers of brick
or other masonry components.
Ballast –
Smooth stone, paving systems or aggregate used to hold down loosely laid roofing
materials.
Bar joist, open web
joist or steel joist – A shop-fabricated, truss-like piece used for
the support of floors and low-slope or flat roofs. The web of a truss is fabricated
of round steel bars. The top portion of the truss includes a pair of steel
angles and the bottom portion consists of a pair of steel angles or round
steel bars.
Base Flashing
– Strips of roof membrane used to seal the junction between a low-slop
roof and an abutting walls or parapet.
Batten –
Normally a wood strip that is used between rigid insulation boards to secure
roof membrane in a low-slop roof. Batten is also used as a metal strip in
metal roofing to cover the metal seams.
Bitumen –
Both clay tar pitches and asphalt are the basic bitumen for roofing applications.
A common name for amorphous, mixture of complex hydrocarbons derived from
petroleum or coal.
Blister –
As the word suggests, a roofing bump or protrusion produced from air vapor
trapped under pressure usually at the membrane substrata interface of between
felt plies of roofing systems.
Blocking –
Solid wood piece used across floor joists or rafters under the unsupported
edges of plywood. The term is also used for nailers on a roof.
Brick – Brick
made for building – common – that is not decorated with texture,
color or glaze.
Brick facing
– Brick of select clays made for exterior or interior finished facing,
which may be decorated, textured, colored or glazed.
BTU / British Thermal
Unit – A unit of energy in the US customary system of units. 1 BTU
is the amount of heat required to raise the temperature of 1 lb. Of water
1 degrees F.
Built-up-roof-membrane
– Alternating and continuous layers or plies of semi-flexible roofing
materials such as saturated felts alternating with layers of bitumen and then
surfaced with mineral aggregate and/or asphalt materials.
Cant Strip– A
strip of wood or other material with a triangular profile. It is used as a
transition piece between a low-slope roof and an abutting wall or curb. Can
strips are usually not used with a single-ply roof membrane because of the
membrane’s flexibility.
Cap Flashing or Counter
flashing – A sheet metal flashing to cover and also protect the upper
edges of a membrane base flashing or an underlying metal flashing from the
weather.
Cap Sheet –
Mineral surface coated felt for the top ply of built-up roofing membranes.
Caulking –
Method of applying a tight joint to prevent water infiltration.
Cleat – A
continuous metal plate or a metal angle piece used to secure two components
together. A cleat is used to secure metal copings on masonry walls.
Coal Tar Pitch
– Solid bitumen derived from coal tar, which is used as a waterproofing
agent for level or built-up roofs with minimal slope.
Coated Felt –
Saturated with asphalt and then coated with harder, viscous asphalt that increases
the felt’s resistance to moisture.
Cold Flow – A
slow deformation of material/substance at room or below room temperature.
Cold-process roofing
– Bituminous membrane layers of coated felt adhered to cold-applied asphalt
roof cement and surfaced withemulsified
asphalt roof coating.
Coping –
Material formed as a cap to finish off the top of a wall to prevent the masonry
structure from water penetration and throws the water off the structure.
Course –
Horizontal and continuous rows of masonry, bonded together to create a masonry
structure.
Cricket –
An elevated portion of a roof, which is construction to divert rainwater to
drains.
D
Delaminating–
Separation of felt plies of a built-up roofing membrane or separation of insulation
boards into a horizontal strata.
Diffusion –
The movement of water vapor through a building component usually caused by
the vapor pressure difference across the two sides of the component.
Downspout –
a vertical pipe to carry water from a roof scupper or a roof gutter.
Drain or roof drain
– An outlet on a low-slope roof for the discharge of rainwater.
E
Eave – The
edge of a steep roof that may or may not project beyond the wall of the façade.
Epoxy – A
synthetic thermosetting resin that produces a hard, chemical-resistant coating
and adhesive.
Expansion joint
– To allow for movement and to prevent cracking due to temperature changes
and normal expansion and contraction, a bituminous fiber strip used to separate
blocks or units of concrete.
F
Felt– Flexible
sheet used in roofing systems.
Fire Resistance –
The ability of a portion of the building or materials that resist fire.
Fish mouth - Membrane
defects that consists of an opening in the edge lap of a felt in a member
that is built up. This is the result of a wrinkled edge.
Flagstone –
A flat stone that is between 1” to 4” thick. They are used for steps,
floors and outside pavers.
Flashing –
A device that seals the necessary membranes at walls and roof interruptions.
Flood coat –
A layer of bitumen poured over a built-up roof that is subsequently covered
with aggregate.
G
Galvanize –
To coat with zinc for corrosion resistance.
Gauge – A
measure of the thickness of metal sheets or wires.
Glaze coat –
A protective coating of bitumen that is rolled onto the lower plies and/or
the top ply of a built-up membrane when additional felts or flood coat / aggregate
surfacing is not installed immediately during a roof installation.
Grain – A
unit to measure the mass of water vapor. 1lb = 7,000 grains.
Gravel Stop –
Provides a finished edge detail for a roof as well as stopping loose aggregate
and other waste from washing off the roof.
Grout – A
cement material mixture, mixed with water to create a paste used to flow between
separate materials such as tile, stone, and copping stones.
H
Header –
Bricks laid lengthwise along a wall service as a bond. It is generally used
to tie two Wythe's of masonry together.
Hem – The
edge created by folding sheet metal over itself.
Hip – The
edge in a sloping roof formed by the intersection of two sloping roof planes.
Hip Roof –
Roof that includes hips.
Hollow walls –
A wall built of solid masonry units laid in such a way to provide an air space
within a wall.
HVAC – Heating,
ventilation, and air conditioning.
I
Insulation –
A material specifically created to retard the flow of heat.
L
Lintel –
A horizontal structure that supports the load over an opening of a door or
window.
M
Masonry –
Brick, concrete, concrete-block, gypsum-block, hollow tile, stone, and other
building units that are bonded together with mortar to form a wall, pier or
similar type of mass.
Mastic – Same
as roofer’s cement.
Membrane –
Roofing covering that is semi-flexible that provided the waterproofing component
to a roofing system.
Mineral-surfaced sheet
– Asphalt saturated felt that is coated on one or both sides and also
then surfaced on the exposed side with mineral granules.
Mortar –
Cement materials and aggregate, sometimes with additional mixtures, formed
into a plastic state with water for use in bonding masonry units.
N
Neoprene –
Synthetic rubber used in single-ply, membrane and flashing materials.
NRCA – National
Roofing Contractors Association.
P
Parapet Wall –
A section of the wall extending above the roof level.
Pitch pocket –
A flanged, cylinder installed around a column or duct or other roof penetrations
a filled with bitumen or plastic cement to seal the joints.
Ply – Felt
layers in a built-up roof membrane.
Pointing –
The process of pushing mortar into the joints of brickwork.
Ponding –
Pool of water created by poor drainage or depressions in a roof or where the
roof is higher than the drainage system.
Protected membrane
roof (PMR) – Roof installation with the insulation on top of the
membrane (instead of vice versa).
R
Reglet –
A horizontal groove where a wall meets the roof surface to anchor flashing.
Ridging –
A membrane defect characterized by an upward displacement of the roofing membrane.
Reinforced brick masonry
(RBM) - A brick unit with metal imbedded into it such that the two materials
act together as a resisting force.
Reveal –
A recess (example: metal U channel) that is visible from the surface of the
wall back into the frame placed between the jambs.
Roll Roofing –
Coated felts supplied in rolls, which are designed for use without field,
applied surfacing work.
S
Scupper –
The channel through the parapet, designed for peripheral roof drainage. This
safety overflow limits the accumulation of ponded rainwater caused by drains
clogged with leaves and debris.
Scuttle –
A hinged or loose cover for a curbed roof opening to provide access to the
roof.
Seam – A
joint formed by mating two separate sections of a material.
Shingle –
A term used with small units of steep roofing that overlap each other to shed
water off the roof.
Shingling –
An information method of laying felts in a built-up roof membrane.
Siding –
An exterior wall finish or either horizontal or vertical panels.
Smooth-surfaced roof
– Built up roofing membrane surfaced with a layer of hot mopped asphalt
or cold applied asphalt-clay emulsion or asphalt cutback.
Soffit –
The underside of an arch.
Soldier –
Bricks laid on edge making the longest dimension running parallel to the building’s
face.Solid Wall – a wall of solid masonry units, with the spaces between
the units filled completely with mortar.
Solvent –
A liquid that dissolves or thins a viscous liquid and evaporates during the
drying process.
Spall – A
power surface removed from the faces of bricks, stone or masonry.
Stack – A
chimney or any similar structure that contains a flue for the discharge of
gases and smoke.
Stucco –
An outside plaster made with Portland cement.
T
Tear off –
The removal of a failed roofing system.
Thermal insulation
– A roofing term, which means insulation.
Thermal shock
– Stress or “shock” due to sudden temperature change in the
roof membrane.
U
Underwriters Laboratories,
Inc. (UL) – An organization that tests and rates roof assemblies
for resistance to fire and wind lifting ability.
V
Veneer –
A facing masonry material attached to the backing.
Vent – An
opening designed to carry water vapor and gases from the inside of a building
to the outside.
W
Wall ties –
Strips of metal used for tying a facing veneer to a wall – inside or
outside.
Water table –
A slight projection of masonry designed as a decorative element to deflect
water off a building.