These terms and commentary could well help you with reporting and/or determining loss issues. I would suggest you save them in bookmarks or print to take with you in folder.
Glossary of Roofing Terms
– A steep slope system
that is used for visual impact or aesthetics and typically require a
supporting deck with a minimum slope of 3:12. Architectural panels
usually have low seam heights of 1 inch to 1-1/2” inches and do not use
sealant between seams. Due to the low seam height and no sealant in the
seams, architectural panels shed water but are not watertight and
therefore require an underlayment below the panels to create a
panels have one leg of the standing seam panel different from the other
so that these legs in adjacent panels may be joined without the use of
a seam cap. These asymmetrical legs usually “snap” together in a
male/female connection. Examples of Garland asymmetrical panels are
R-Mer Loc and R-Mer Clad.
– The built-up roof is a
multi-layer roof system that consist of multiple plies of
reinforcements laid in a waterproofing bitumen. The alternating plies
of reinforcement and waterproofing bitumen provide redundancy to the
roof system. The reinforcements on a BUR are typically fiberglass
felts, which provide strength to the BUR. The waterproofing bitumen can
be asphalt or coal tar. The BUR is surfaced with gravel or a liquid
- A cool roof is
defined as a roof surface that has both high reflectivity and high
emissivity. High reflectivity requires the surfacing material to
reflect solar energy away from the surface. High emissivity requires
radiating heat energy away from the surface. Roofs undergo significant
expansion and contraction as they heat and cool throughout the day.
Heat absorbed by the roof can also accelerate degradation by
ultraviolet rays and water. A reflective roof can reduce the amount of
thermal shock that occurs on the roof surface and make the roof last
– The ability of a membrane
to be stretched and lengthened by force to accommodate movement.
Roofing membranes have forces exerted on them from the building
movement and the membrane must be able to accommodate these movements.
If a 100 foot building expands by 3%, the walls would need to move 3
feet. This would increase the stresses on the building to the point of
structural failure. The United States Army Corp of Engineers estimates
that buildings move less than 1%.
- A registered
trademark of the U.S. government. The ENERGY STAR® Program* represents
a voluntary partnership between businesses and organizations and the
federal government to promote energy efficiency and environmental
activities. ENERGY STAR® labeled roof products are reflective and lower
roof surface temperature by up to 100°F., decreasing the amount of heat
transferred into a building. ENERGY STAR® labeled roof products are
designed to help save money on utility bills and reduce energy waste.
Ninety percent of the energy in the United States is generated by
burning fossil fuels, which creates the air pollution associated with
smog, acid rain, and global climate change. By reducing the amount of
energy needed to cool buildings, ENERGY STAR® labeled roof products
help to reduce the production of these air pollutants. Additionally,
reflective roof products can help reduce the "heat island effect," a
phenomenon in which cities can be 2 to 8°F. warmer than the surrounding
countryside. Such heat islands occur, in large part, because many
buildings and paved surfaces are designed with dark materials that
absorb heat from the sun. This heat is released at night, causing the
air temperature to remain high. The resulting elevated temperature
leads to an increased demand for air conditioning in buildings,
increased fuel use for vehicle air conditioning, increased levels of
smog, and associated increased levels of heat-related and smog-related
health problems. Installing reflective roofs helps reduce the heat
island effect, decreasing the amount of smog in the air and benefiting
the entire community.
– The ability of a roof top material to act as a barrier to the spread
of fire and confine it to the area of origin. There are established
test procedures for external fire exposure to classify roof systems
into Class A, B, or C ratings. Underwriters Laboratories test method
790 established this procedure which ASTM adopted and named ASTM E-108.
Therefore UL 790 and ASTM E-108 are the same test with different names.
Factory Mutual and Warnock Hersey both use ASTM E-108 as the primary
test for fire resistance.
– Is a term used to describe when two metal panels are joined in a
shingle fashion. The two panels can either be overlapped and fastened
or folded and interlocked. Flat seam systems are made out of metal,
which makes the roof durable, 100% recyclable and very low maintenance.
Low Temperature Flexibility
-The ability of a membrane to remain flexible (resist cracking) after
it has been exposed to low temperatures. Roofing membranes encounter
extreme weather conditions and resisting cracking at low temperatures
is vital to the long-term performance of roofing membranes in colder
climates. Low temperature flexibility is directly related to the amount
of rubber incorporated in the membrane. Since the rubber modifier also
increases UV protection, the better the low temperature flexibility,
the greater UV protection a membrane will have. Therefore, low
temperature flexibility is a vital criteria for warmer climates as well.
– Mechanical finishes are raised features on metal panels. These
features are mesa patterns, pencil lines, or stucco embossing.
Mechanical finishes help to reduce oil canning and strengthen the
panels. Garland uses mechanical finishes to increase the performance of
our metal roof systems, and also to add to their aesthetic appeal.
– To create a curved profile in a metal panel, a machine is used to
form the panel to a desired radius, hence the term, mechanically
curved. This becomes important, because some manufacturers do not
mechanically curve their panels; installers simply force straight
panels to conform to the curve in a roof. This can cause many problems
such as binding of standing seam panels on their clips, oil canning,
and of course, failure. Garland has the ability to mechanically curve
our symmetrical panels to the tightest radius available in the industry.
– The modified bitumen roof system is a hybrid built-up roof. It has
the benefits of the built in redundancy of the BUR, along with the
added strength, flexibility and UV resistance of a modified membrane.
The membrane consist of an asphalt and polymer blend which allow the
asphalt to take on characteristics of the polymer. There are several
surfacing option for this system which include a factory applied
mineral surface, a gravel surface laid in bitumen or a liquid applied
coating that is typically reflective in nature.
– Oil canning is triggered by thermal expansion and contraction of
metal roof panels and flashing. Oil canning can be seen as a rolling or
washboard bending of a piece of metal. Causes of oil canning can be,
binding of systems with limited thermal movement, and poor
manufacturing techniques. To limit oil canning to a minimum, Garland
designs our roofing systems with unlimited thermal movement, uses high
quality roll forming equipment, and adds mechanical finishes to metal
roof panels and accessories.
Post Consumer Recycled Material
- Post consumer recycled materials are those materials which have
already served their initial purpose to a consumer and are then
reclaimed rather than being discarded in traditional landfills. Common
post consumer recycled materials include tires, aluminum cans,
newspapers, plastic bottles and glass. Innovative companies are finding
new ways to break down these materials and incorporate them into their
processes. Post consumer waste is generally recognized as being more
environmentally friendly because once materials reach the consumer they
are more likely to end up in landfills.
Post Industrial Recycled Material
- Post industrial recycled materials are those materials that have been
recovered or otherwise diverted from the waste stream during the
manufacturing process. This does not include used, reconditioned or
– The reinforcing fabric that acts as a carrier for the polymer
modified bitumen. The scrim contributes to performance characteristics
of the finished product that include tensile strength, puncture
resistance and fire resistance. The two primary fabrics for scrim
include fiberglass and polyester. There is also a combination scrim
which incorporates both of these fabrics.
– Is a term used to describe the adjoining of two metal panels together
with an upturned portion of the metal. The two panels are held together
with concealed clips. The joinery raises the seam above the drainage
plain. Standing seam systems are made out of metal, which makes the
roof durable, 100% recyclable and very low maintenance.
– A low slope system that can support their own weight without a deck.
Structural panels usually have high seams 1-3/4” to 3” and can handle
slopes as low as 1/4:12. The panels are watertight and can span long
distances. Since a deck is usually not required a structural system can
end up being a lower cost alternative than an architectural panel with
a supporting roof deck.
– A symmetrical panel design has both legs of the standing seam panel
identical in size and shape. This is typically found in panel system
where a cap is used to seam the panels together. Benefits of a
symmetrical panel are easy replacement, and tighter curving radiuses.
Examples of Garland symmetrical panels are our structural system, R-Mer
Span, and our architectural system, R-Mer Seam. Due to its symmetrical
design with a seam cap, R-Mer Span has the highest rated uplift
pressures resistance in the industry.
– The maximum force a material can bear without tearing apart. Roofing
membranes should have sufficient tensile strengths to resist the severe
stresses caused by internal and external forces imposed on it. Thermal
shock, caused by sudden heating or cooling of a membrane, causes stress
that a roofing membrane must be able to withstand. The greater the
tensile strength a membrane has, the greater resistance it will have to
splitting, breaking or tearing throughout its life. Many roofing
publications, including the NRCA’s Roofing and Waterproofing Manual and
Dr. H.O. Laaly’s The Science and Technology of Traditional and Modern
Roofing Systems, confirm that superior tensile strength has a direct
correlation to the long-term performance of a membrane.
– A condition where heat or cold can be conducted through a metal
fastener or opening from the underside of the roof assembly to the
outside of a roof surface. Properly designed roof assemblies will
eliminate thermal bridging from occurring.
Unlimited Thermal Movement
– All materials experience the stresses related to heating and cooling
of the roof surface. In some cases, temperatures of a roof surface can
vary by up to 200 degrees F throughout the course of a day. The term
“unlimited thermal movement” describes designing a roof system to
accommodate all of the expansion and contraction that a roof may
experience throughout a 200 degree cycle. With a metal roof, this
movement can be in the order of several inches. The Garland Standing
Seam, one-piece clip design allows the metal roof panels to move freely
through an unlimited range of expansion and contraction. Garland’s flat
seam metal roof system, R-Mer Lite is also designed with the unlimited
thermal movement concept.
– The ability of a roof top material to prevent degradation caused by
exposure to Ultraviolet rays. Heat and UV are two primary causes of
premature roof failure. UV rays cause the oils in a roofing membrane to
dry out. These oils provide pliability and leads to the membrane
cracking when they are dried out. The addition of unique polymer blends
provides protection to the membrane from cracking by maintaining the
membrane’s pliability. The resistance to UV degradation prevents
membrane cracking which prolongs the waterproofing life of the membrane.
–A wind uplift rating is not the miles per hour of wind speed a roof
system can withstand, but rather, the negative pressure (pounds per
square foot) that occurs when the inside air pressure of a building is
greater than the air pressure outside the building. As wind passes over
a building, there is a decrease in external air pressure on roof and
some down wind surfaces. As this external decrease in air pressure
occurs, there is a corresponding increase in air pressure differential
between the inside and the outside of the building. As the internal air
pressure tries to equalize itself with the external pressure, the
resulting force, identified as wind uplift forces, attempts to lift the
roof off the building. Most parts of North America require a 1-60 or
1-90 uplift resistance. Coastal regions and high wind areas may require
additional uplift resistance.
Success is not final, failure is not fatal: it is the courage to continue that counts.