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Aggregate:
A surfacing material or ballast for a roof system. Aggregate
can be rock, stone, crushed stone or slag, water-worn
gravel, crushed lava rock or marble chips.
Algae discoloration:
A type of roof discoloration caused by algae, also called
fungus growth.
Alligatoring:
Alligatoring is term used to describe the cracking of
surfacing bitumen on a built-up roof. These cracks are the
result of the limited tolerance of asphalt to thermal
expansion or contraction, and produce a pattern that
resembles an alligator's hide.
Attic:
The open area above the ceiling and under the roof deck of a
steep-sloped roof.
Asphalt shingle:
a shingle manufactured by coating a reinforcing material
(felt or fibrous glass mat) with asphalt and having mineral
granules on the side exposed to the weather.
Back
surfacing:
Fine mineral matter applied to the back side of shingles to
keep them from sticking.
Base flashing:
That portion of the flashing attached to or resting on the
deck to direct the flow of water onto the roof covering.
Battens:
1"x2"x4' wood strips nailed to the roof, upon which the
field tile hangs.
Bird stop:
In addition to preventing birds from nesting in the hollows
of the tile, this length of formed metal or foam elevates
the first course of tile so that it is positioned at the
same angle as subsequent courses.
Blisters:
Bubbles that may appear on the surface of asphalt roofing
after installation.
Built-up roof:
An outer covering of a comparatively flat roof, consisting
of several layers of saturated felt. As laid, each layer is
mopped with hot tar or asphalt. The top layer is finished
with a mineral or rock covering and a special coating.
Bundle:
A package of shingles. There are 3, 4 or 5 bundles per
square.
Butt edge:
The lower edge of the shingle tabs.
Caulk:
To fill a joint with mastic or asphalt cement to prevent
leaks.
Chalk line:
A line made on the roof by snapping a taut string or cord
dusted with chalk. Used for alignment purposes.
Class "A":
The highest fire-resistance rating for roofing as per ASTM
E-108. Indicates roofing is able to withstand severe
exposure to fire originating from sources outside the
building.
Class "B":
Fire-resistance rating that indicates roofing materials are
able to withstand moderate exposure to fire originating from
sources outside the building.
Class "C":
Fire-resistance rating that indicates roofing materials
are able to withstand light exposure to fire originating
from sources outside the building.
Closed cut
valley: A method of valley treatment in which shingles
from one side of the valley extend across the valley while
shingles from the other side are trimmed two inches from the
valley centerline. The valley flashing is not exposed.
Coating:
A layer of viscous asphalt applied to the base material into
which granules or other surfacing is embedded.
Collar:
Pre-formed flange placed over a vent pipe to seal the roof
around the vent pipe opening. The collar is also called a
vent sleeve.
Color-through: During manufacturing, the color is mixed
throughout the roofing material to become an integral part
of it. When the product is cut, the affected area shows the
same color as the surface.
Concealed
nail method: Application of roll roofing in which all
nails are driven into the underlying course of roofing and
covered by a cemented, overlapping course. Nails are not
exposed to the weather.
Condensation: The change of water from vapor to liquid
when warm, moisture-laden air comes in contact with a cold
surface.
Counter
flashing: That portion of the flashing attached to a
vertical surface to prevent water from migrating behind the
base flashing.
Course:
A row of shingles or roll roofing running the length of the
roof.
Coverage:
Amount of weather protection provided by the roofing
material. Depends on number of layers of material between
the exposed surface of the roofing and the deck; i.e.,
single coverage, double coverage, etc.
Cricket:
A peaked saddle construction at the back of a chimney to
prevent accumulation of snow and ice and to deflect water
around the chimney.
Cutout:
The open portions of a strip shingle between the tabs.
Deck or
Decking: The structural "skin" of a roof over which
roofing in applied. Most new homes have decking made of
plywood. There are four main types of decking commonly used
on residential roofing projects:
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Plywood: Plywood is strong, durable, and light. It
comes in many grades with ratings from A to D. Use only
exterior grade plywood for decking. The thickness of
plywood depends on the spacing of the rafters.
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OSB:
Oriented strand board (OSB) is cheaper than plywood,
but not as strong as plywood, and does not hold nails as
well as plywood. One side has a slip resistant coating
and should be placed facing up.
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Tongue
and groove 2-by-6: If a roof will be seen from the
inside (no ceiling installed), tongue and groove is
used. It is a wood decking that provides great
insulation without additional rigid roof insulation in
moderate climates. Also, the boards can be painted or
stained on the inside to match the interior.
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Step
sheathing: Step sheathing is used alone or in
combinations with solid sheathing for installation of
tiles or shakes. Step sheathing allows air circulations
under the tiles by using 1-by-6 or 2-by-6 boards that
are evenly spaced so that air can move under the tiles
or shakes.
Dimensional shingle:
a shingle that is textured, overlayed, or laminated and
designed to produce a three-dimensional effect. Similar to
Laminated shingle and Architectural shingle.
Dormer:
A framed window unit that projects through the sloping plane
of a roof.
Double
coverage: Application of asphalt roofing such that the
lapped portion is at least two inches wider than the exposed
portion, resulting in two layers of roofing material over
the deck.
Downspout:
A pipe for draining water from roof gutters. A downspout is
also called a leader.
Drip edge:
A non-corrosive, non-staining material used along the eaves
and rakes to allow water run-off to drip clear of underlying
construction.
Dutch lap
method: Application of giant individual shingles with
the long dimension parallel to the eaves. Shingles are
applied to overlap adjacent shingles in each course as well
as the course below.
Eaves:
The horizontal, lower edge of a sloped roof.
Eaves
flashing: Additional layer of roofing material applied
at the eaves to help prevent damage from water back-up.
Edging
strips: Boards nailed along eaves and rakes after
cutting back existing wood shingles to provide secure edges
for re-roofing with asphalt shingles.
Edge
venting: The installation of a vent material along the
roof edge (e.g., Starter Vent) as part of a ventilation
system. Edge vent material should be used in conjunction
with other venting material (e.g., ridge vent) as it not
intended for use by itself.
Exposed
nail method: Application of roll roofing in which all
nails are driven into the cemented, overlapping course of
roofing. Nails are exposed to the weather.
Exposure:
Portion of the shingle exposed to the weather. Exposure is
measured from the butt of one shingle to the butt of the
next.
Fascia:
Horizontal trim at the eaves that covers the rafter ends.
Feathering
strips: Tapered wood filler strips placed along the
butts of old wood shingles to create a level surface when
re-roofing over existing wood shingle roofs. Feathering
strips are also called horse feathers.
Felt: A
flexible sheet that is saturated with asphalt and used as an
underlayment, sometimes called "tar paper"
Fiber-cement: A roofing material that has cellulose
(wood fiber) mixed into it. Cellulose absorbs water and can
add greatly to the roof's weight, while reducing its
longevity.
Fiberglass
mat: An asphalt roofing base material manufactured from
glass fibers.
Flashing:
Pieces of metal or roll roofing used to prevent seepage of
water into a building around any intersection or projection
in a roof such as vent pipes, chimneys, adjoining walls,
dormers and valleys. Galvanized metal flashing should be
minimum 26-gauge. There are 4 main types of flashing used in
residential roofing systems:
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Valley
flashing: This flashing is used in open valleys of
the roof. Most often leaks are found in the valley
flashings due to flashing that is nailed to tightly to
the decking or shingles that are not trimmed far enough
off the flashing.
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Plumbing vent flashing: Plumbing vent flashing
prevents rainwater from running into holes cut for pipes
in the roof. This flashing is sold according to the size
of the vent pipe and the roof angle. Roofing material is
installed over the flashing.
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Lead
flashing: When working with tile roofs, lead
flashing is used. In the case of a plumbing vent
flashing, the lead flashing is actually molded to the
shape of the tile's surface. Then the top of the lead
flashing is covered by the next tile to prevent water
from seeping under the flashing.
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Step
flashing: When a chimney or dormer wall intercepts
the slope of the roof, step flashing is used. Step
flashing is usually a metal piece that is bent in the
middle, so that one end lays on the roof, and the other
against the vertical wall of the dormer or chimney.
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Flashing
is one of the most important elements of the roof
because it seals the seams and joints of the roof--the
locations where leaks are most likely to occur. Often,
flashing is not maintained well, or installed correctly
in the first place. Check for the following signs that
your flashing needs maintenance or repair:
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Rusting of metal flashing
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Excess
leaves and debris in valleys or seams of the roof
(can lead to rusting and corroding of the metal)
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Prolonged exposure to the elements such as moisture,
UV rays, climate changes--especially when asphalt
compounds or caulking material is used. Look for
cracks, loss of elasticity and delamination.
In many cases
the flashing can be cleaned and then repaired, relaminated
or repainted (even in the case of rust). In other cases, the
flashing may need to be replaced.
Flashing
cement: An asphalt-based cement used to bond roofing
materials. Flashing cement is also known as mastic.
Free-tab
shingles: Shingles that do not contain factory-applied
strips or spots of self-sealing adhesive.
Gable:
The upper portion of a sidewall that comes to a triangular
point at the ridge of a sloping roof.
Gable roof:
A type of roof containing sloping planes of the same pitch
on each side of the ridge. A gable roof typically contains a
gable at each end.
Gambrel roof:
A type of roof containing two sloping planes of different
pitch on each side of the ridge. The lower plane has a
steeper slope than the upper. A gambrel roof usually
contains a gable at each end, just like a standard gable
roof.
Granules:
Ceramic-coated colored crushed rock that is applied to the
exposed surface of asphalt roofing products.
Gutter:
The trough that channels water from the eaves to the
downspouts.
HEX shingles:
Shingles that have the appearance of a hexagon after
installation.
Hip:
The inclined external angle formed by the intersection of
two sloping roof planes. The hip runs from the ridge to the
eaves.
Hip roof:
A type of roof containing sloping planes of the same pitch
on each of four sides. A hip roof contains no gables.
Hip shingles:
Shingles used to cover the inclined external angle formed by
the intersection of two sloping roof planes.
Ice dam:
Ice dams occur when snow melts near the ridgelines of warm
roofs (roofs without adequate ventilation). As the water
runs down the roof to the overhang, it cools and freezes. If
the snow continues this melt and freeze process, an ice dam
can form that can seep under the shingles, through the
decking and into the house. This, of course, can cause
serious roof leaks--even in freezing temperatures.
The best
prevention to ice dams is a well-ventilated (cool) roof.
Additional protection for your roof can be applied with an
impermeable ice and water membrane. The membrane is
installed on top of the decking, under the roofing material.
Temporary prevention of ice dams can also be done through
the use of electric cables along the eaves of the roof
(where the dams usually form). However, new ice dams can
form above the cables and still cause extensive damage.
Another emergency solution to ice dams is to fill a sock or
nylon with calcium chloride. Lay the stocking vertically
across the ice dam. The calcium chloride will melt the ice
and release the water so that it can drain outside, and not
inside your roof.
Intake Ventilation:
The part of a ventilation system used to draw fresh air in.
Usually vents installed in the soffit or along the eaves of
a building.
Interlocking shingles:
Individual shingles that mechanically fasten to each other
to provide wind resistance.
Joists:
Any of the small timbers or metal beams ranged parallel
from wall to wall in a structure to support a floor or
ceiling.
Laminated shingles:
Strip shingles containing more than one layer of tabs to
create extra thickness. Laminated shingles are also called
three-dimensional shingles.
Lap:
To cover the surface of one shingle or roll with another.
Lap
cement:
An asphalt-based cement used to adhere overlapping plies
of roll roofing.
Lean-to roof:
A roof with one slope only that is built against a higher
wall.
Life-cycle cost:
The total lifetime cost of a roof. Calculated by adding
maintenance costs to the installed price, then deducting the
added value the roof provides when the home is resold.
Low slope
application:
Method of installing asphalt shingles on roof slopes
between two and four inches per foot.
Mansard roof:
A type of roof containing two sloping planes of different
pitch on each of four sides. The lower plane has a much
steeper pitch than the upper, often approaching vertical.
Contains no gables.
Mastic:
An asphalt-based cement used to bond roofing materials. Also
known as flashing cement.
Metal drip edge:
A narrow strip of non-corrodible metal used at the rake and
eave to facilitate water runoff.
Mineral-surfaced roofing:
Asphalt shingles and roll roofing that are covered with
granules.
Modified Bitumen:
Roofing asphalt that has been blended with some of a broad
range of materials which improve its performance
characteristics.
Nesting:
A method of re-roofing with new asphalt shingles over old
shingles in which the top edge of the new shingle is butted
against the bottom edge of the existing shingle tab.
New construction:
Installing a roof system on new construction.
No-cutout shingles:
Shingles consisting of a single, solid tab with no cutouts.
Non-prorated warranty:
A warranty which provides full replacement costs for the
item(s) covered during the full term of the warranty. In
contrast, a prorated warranty merely reimburses a percentage
of replacement costs, depending on the age of the roof.
Non-veneer panel:
Any wood based panel that does not contain veneer and
carries an APA span rating, such as wafer board or oriented
strand board.
Normal
slope application: Method of installing asphalt shingles
on roof slopes between 4 inches and 21 inches per foot.
Open valley:
Method of valley construction in which shingles on both
sides of the valley are trimmed along a chalk line snapped
on each side of the valley. Shingles do not extend across
the valley. Valley flashing is exposed.
Organic felt:
An asphalt roofing base material manufactured from cellulose
fibers.
Organic shingle:
An asphalt shingle reinforced with organic material
manufactured from cellulose fibers.
Overhang:
That portion of the roof structure that extends beyond
the exterior walls of a building.
Pallets:
Wooden platforms used for storing and shipping bundles of
shingles.
Parapet:
A low protective wall that extends above the roofline or
balcony for support.
Pitch:
Also known as "slope", pitch is the measure of how "steep" a
roof is. For example, if a roof is "4 in 12", the roof rises
4 inches for every horizontal run of 12 inches. The pitch of
the roof is a big factor in determining the kinds of
materials that can be used and the longevity of the roof.
Usually, a steeper roof (higher pitch) will last longer due
to its better drainage capabilities.
Plastic cement:
A compound used to seal flashings and in some cases to seal
down shingles as well as for other small waterproofing jobs.
Where plastic cement is required for sealing down shingles,
use a dab about the size of a half dollar unless otherwise
specified.
Ply:
The number of layers of roofing: i.e. one-ply, two-ply.
Racking:
Roofing application method in which shingle courses are
applied vertically up the roof rather than across and up.
Not a recommended procedure.
Rafter:
The supporting framing member immediately beneath the deck,
sloping from the ridge to the wall plate.
Rake:
The inclined edge of a sloped roof over a wall from the
eave to the ridge.
Random-tab shingles:
Shingles on which tabs vary in size and exposure.
Release
tape:
A plastic or paper strip that is applied to the back of
self-sealing shingles. This strip prevents the shingles from
sticking together in the bundles, and need not be removed
for application.
Re-cover (overlay):
The installation of a new roof system over an existing
system without removing an existing system.
Re-roofing:
Installing a new roof system on a building that is not
new.
Ridge:
The uppermost, horizontal external angle formed by the
intersection of two sloping roof planes.
Ridge shingles:
Shingles used to cover the horizontal external angle formed
by the intersection of two sloping roof planes.
Rise:
The vertical distance from the eaves line to the ridge.
Roll roofing:
Asphalt roofing products manufactured in roll form.
Roofing
tape:
An asphalt-saturated tape used with asphalt cements for
flashing and patching asphalt roofing.
Run:
The horizontal distance from the eaves to a point directly
under the ridge. One half the span.
Saturant:
Asphalt used to impregnate an organic felt base
material.
Self-sealing shingles:
Shingles containing factory-applied strips or spots a
thermal sealing tab cement to firmly cement the shingles
together automatically after they have been applied properly
and exposed to warm sun temperatures. In warm seasons, the
seal will be complete in a matter of days. In colder
seasons, sealing time depends on the temperature and amount
of direct sunlight hitting the shingles. Hand sealing with
plastic cement should be done to ensure sealing in winter.
Self-sealing strip or spot:
Factory-applied adhesive that bonds shingle courses together
when exposed to the heat of the sun after application. Also
known as self-sealing cement.
Selvage:
That portion of roll roofing overlapped by the succeeding
course to obtain double coverage.
Shading:
Slight differences in shingle color that may occur as a
result of normal manufacturing operations.
Sheathing:
Exterior grade boards used as a roof deck material.
"Step sheathing" is used alone or in combinations with solid
sheathing for installation of tiles or shakes. Step
sheathing allows air circulations under the tiles by using
1-by-6 or 2-by-6 boards that are evenly spaced so that air
can move under the tiles or shakes.
Shed roof:
A roof containing only one sloping plane. Has no hips,
ridges, valleys or gables.
Single coverage:
Asphalt roofing that provides one layer of roofing material
over the deck.
Slope:
The degree of roof incline expressed as the ratio of the
rise, in inches, to the run, in feet.
Smooth-surfaced roofing:
Roll roofing that is covered with ground talc or mica
instead of granules (coated).
Soffit:
The finished underside of the eaves.
Soil stack:
A vent pipe that penetrates the roof.
Span:
The horizontal distance from eaves to eaves.
Specialty eaves flashing membrane:
A self-adhering, waterproofing shingle underlayment designed
to protect against water infiltration due to ice dams or
wind-driven rain.
Square:
A unit of roof measure covering 100 square feet.
Square-tab shingles:
Shingles on which tabs are all the same size and exposure.
Starter strip:
Asphalt roofing applied at the eaves that provides
protection by filling in the spaces under the cutouts and
joints of the first course of shingles.
Steep
slope application:
Method of installing asphalt shingles on roof slopes
greater than 21 inches per foot.
Step flashing:
Flashing application method used where a vertical surface
meets a sloping roof plane.
Strip shingles:
Asphalt shingles that are approximately three times as long
as they are wide.
Tab:
The exposed portion of strip shingles defined by cutouts.
Tar paper:
See "Felt"
Tear off:
Removing an existing roof system.
Telegraphing:
A shingle distortion that may arise when a new roof is
applied over an uneven surface.
Three-dimensional shingles:
See laminated shingles.
Three-tab shingle:
The most popular type of asphalt shingle usually 12" x 36"
in size with three tabs.
Top lap:
That portion of the roofing covered by the succeeding course
after installation.
UL:
Underwriters Laboratories, Inc.
UL label:
Label displayed on packaging to indicate the level of fire
and/or wind resistance of asphalt roofing.
Underlayment:
A layer of asphalt saturated (sometimes referred to as tar
paper) which is laid down on a bare deck before shingles are
installed to provide additional protection for the deck.
Valley:
The internal angle formed by the intersection of two sloping
roof planes to provide water runoff.
Vent:
Any outlet for air that protrudes through the roof deck
such as a pipe or stack. Any device installed on the roof,
gable or soffit for the purpose of ventilating the underside
of the roof deck.
Vent sleeve:
See collar.
Woven Valley:
Method of valley construction in which shingles from both
sides of the valley extend across the valley and are woven
together by overlapping alternate courses as they are
applied. The valley flashing is not exposed.
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