Asphalt shingles have been used successfully in cold climates for over one hundred years.
Improved application efficiency, and more importantly, enhanced long-term shingle
performance, can be achieved by following the cold weather application recommendations
outlined below:
• Be sure to follow the manufacturer’s installation instructions carefully, as most building
codes require, including manufacturer recommendations about cold temperature
application and proper storage and handling of accessory components used in the
installation of an asphalt shingle roofing system.
• Be very careful when working on sloped roofs. In winter applications, there may be
nearly invisible ice or frost build-up on the roof or deck surface, which can make work
extremely hazardous. It is advisable to wait until the roof surface is free of ice and frost
for safer shingle roof application.
• Use caution when handling bundles of shingles and individual shingles in cold weather
as they may crack, or in severe cases, break apart. Choose an installation temperature
where the shingles are sufficiently flexible to facilitate installation. As with most
materials, asphalt shingles tend to become less flexible as temperature decreases. Refer
to manufacturer instructions for specific directions related to cold weather installation
temperature. Note that when cold, shingle bundles will tend to keep the shape of the
surface upon which they are stacked. When nailing, make sure the shingles are flat;
otherwise, the nail may break through the shingle surface during installation. Avoid
bending, throwing, or dropping bundles of shingles in cold weather. For best results,
store shingles indoors to keep them warm prior to application.
• Use extra care (including warming of shingles) in applications where lifting or bending
the shingle is required, such as racking applications, hip and ridge shingles, or at valleys.
Lifting or bending may cause the shingles to crack or break during or after installation.
• Most asphalt shingles include thermally activated asphalt sealant, which bonds the
shingles together after they are applied to the roof. Sealing time will vary depending on
the slope of the roof, its orientation, and the amount of sun/heat exposure that the
shingles receive. To provide improved protection from wind blow-off in very cold
weather, asphalt shingles can be hand-sealed with an approved asphalt roofing cement
or other adhesive acceptable to the shingle manufacturer and in accordance with their installation requirements.
• Consider the use of open metal valleys in cold weather. Woven and closed cut valleys
require shingles to be bent, which may result in shingle damage.
Additional Considerations
• When re-roofing over an existing roof in cold weather, take extra care to ensure that the
roof surface is smooth and flat. If shingles are affixed to an uneven surface in cold
weather, that uneven appearance may be “locked in.” Even with the return to warmer
weather, the shingles may not be able to completely relax to a smooth looking finished
roof.
• Ensure that the attic space is adequately ventilated.1
• Install polymer modified, self-adhering underlayment as ice dam protection in regions
susceptible to ice damming. Self-adhering underlayment provide protection against
damage from water backup from ice dams that can occur at the eaves of the roof.2

Asphalt saturated felt may be used as an alternative ice dam protection when applied
per the manufacturer’s application instructions and the requirements of the building
code.
• If roof maintenance or inspection is required in cold weather, take special care when
walking on shingles. Shingles applied to an uneven surface, or that are slightly curved or
buckled, are very susceptible to breakage underfoot in frigid weather. For some
sealants, the bond between courses becomes less flexible in cold weather and roof
traffic may break the sealant bond. In such cases, it may be necessary to hand-seal these
shingles.
Certain North American regions receive very high snowfall amounts, requiring snow and ice
removal from the roof. Extreme caution must be taken when removing snow from the roof so
that the shingles are not damaged by shovels, scrapers, or foot traffic.

Introduction
Asphalt shingles have been used successfully in various climate zones around the world, including desert and tropical
regions, for over one hundred years. Improved application efficiency and, more importantly, enhanced long-term
shingle performance can be achieved by following the recommendations outlined below for hot weather storage
and application.
Storage Prior to Use
Always follow the manufacturer’s precautions about stacking bundles and pallets; stacking bundles too high or
double-stacking pallets can indent or deform the shingles over time, particularly in warm weather or when shingles
are exposed to direct sunlight. As a general rule in hot weather, store shingles in a cool dry place in stacks no more
than four feet high. If higher stacking is necessary, it is recommended to use racks or bins so that the weight of the
bundles on the upper pallets does not bear down on the bundles below. Systematically rotate all stock so that the
material that has been stored the longest will be the first to be moved out (i.e. first in, first out).
Although asphalt shingles are designed to withstand direct exposure to the hot summer sun after installation, it is
best not to store the products in direct sunlight prior to installation. Storage in direct sunlight may also cause a
weathering and weakening of the packaging materials, making it awkward to handle the bundles prior to installation.
Removing Shingles from Bundles
Although shingles have a release film to prevent them from sticking to each other in the package, direct sun can
cause the sealant to become more aggressive, making the shingles more difficult to separate and remove from the
bundle. When removing shingles from a warm bundle, follow the manufacturer’s recommendations; some products
may separate better or more easily when removed from the bundle “granule side up” or by quickly snapping the
shingles out of the bundle stack. This helps break the weak bond which may have formed between shingle sealant
and release films, allowing easier separation and minimizing potential shingle damage.
Placement of Shingles on Roof Prior to Installation
Shingles should be kept in bundles or handled in pairs and stacked squarely to maintain shingle sealant alignment
with the release tape until applied. Asphalt shingles become more flexible in hot weather, so avoid rough handling
that may tear the shingles or break the laminating adhesive bond on multi-layer shingles.
Keep bundles as flat as possible during the roof loading process and on the roof.
Do not drape shingles or bundles over the hips or ridges; keep shingles in their packaging until ready to be applied.
During Application
Always be careful when working on sloped roofs. In hot weather applications, the asphalt coating on the shingles will
Recommendations for
Storage and Application
of Asphalt Roofing
Shingles in Hot Weather
soften. Wear soft-soled footwear to minimize foot slippage possibilities and scuffing of the shingles. On steeper
roofs where worker footprints, such as toe or heel marks, are likely to be more concentrated in small areas., use
reasonable care to minimize scuffing and, if necessary, wait until the shingles and ambient temperatures cool.
Ensure roof safety by following all required safety precautions; such precautions should include use of fall protection
devices.
For comfort reasons as well as the safety reasons noted above, on forecasted hot and sunny days it is advisable to
install shingles early in the day before the temperature reaches its maximum. One should also plan the roof
installation to “work around the sun,” i.e. work on the west – and south-facing slopes in the morning and the eastand north-facing slopes later in the day.
In hot weather, shingle pieces trimmed for hips, ridges, rakes, and valleys can quickly adhere to shingles that are
already applied if left on the roof with their sealant strip down. Use good housekeeping practices to minimize shingle
debris on the roof.
Other Considerations
Most asphalt shingles are manufactured with a thermally activated asphaltic sealant which bonds the shingles
together once they are applied to the roof and exposed to a sufficient period of heat from sunlight. If this sealant has
been affected (blinded) by wind-blown dust from the surrounding environment or the job site (e.g. saw dust), the
sealant may not activate even on hot sunny days and the shingles will need to be manually sealed per the shingle
manufacturer’s instructions. On north-facing or steeper slopes the shingles may not seal immediately even in
warmer weather and may require manual sealing as well.
If repairs or other rooftop work is required during hot, sunny weather on existing shingled roofs, the shingles will be
susceptible to the same scuffing and possible damage noted above. Because the shingle sealant bond on existing
roofs is likely to be fully formed , their removal or repair will be difficult to perform without causing shingle tearing
and damage at the sealant interface. In such cases it may be best to wait until the shingles are cooler before
attempting shingle repair. If waiting is not feasible, lightly spraying the shingle surface with a water mist will cool the
shingle surface and may facilitate sealant bond separation. Caution: A wet roof surface can be slippery, so take
appropriate precautions.

Description
Buckling is the result of asphalt shingles not lying flat due to wrinkling of the roofing underlayment or movement of
the wood deck.
Causes
• Exposure of the wood roof deck during new construction or roof replacement can lead to moisture
absorption into the wood. As the wood increases in moisture content, movement of the decking can occur.
• As a new roof is installed, moisture can be trapped in the system and the roofing underlayment can absorb
moisture and wrinkle.
• Inadequate ventilation of the attic space, which restricts free-flow of air directly beneath the roof deck, can
create problems with moisture and temperature management in the attic space that can contribute to
movement of the wood deck. See individual manufacturer recommendations for ventilation requirements.
• Roof decking that is not spaced a minimum of 1/8” can cause buckling due to expansion.
Solutions
• Allow moisture to escape the roofing system. Once the roofing system reaches the proper moisture content,
the roof should lie flat and the buckling problem should not return.
• Remove the shingles that are affected, and where the felt is wrinkled, repair the wrinkles by cutting and renailing the felt so that it is flat, and then replace the shingles.
• Ensure that the attic is properly ventilated according to the latest version of the building code. Proper
ventilation includes free-flow of air directly beneath the roof deck, from the eaves to the ridge.
Prevention
• Use only wood decking materials acceptable to the roofing manufacturer that have been properly
conditioned. Refer to detailed recommendations found in the “How to Minimize Buckling of Asphalt
Shingles” published by APA – The Engineered Wood Association.
• Do not expose decking materials to liquid water either before or after application.
• Cover wood deck materials with asphalt-saturated felt shingle underlayment (ASTM D 226, ASTM D 4869,
ASTM D 6757 or CSA A123.3), then apply shingles as soon as possible.
• Ensure adequate attic ventilation (e.g., a minimum of one square foot net free area per 150 square feet of
attic floor space). See individual manufacturer recommendations for additional ventilation requirements.
• Apply shingles in accordance with shingle manufacturers’ recommendations.
Correction
• Ventilate the attic space to eliminate excess moisture. In some circumstances, the addition of mechanical
exhaust fans may be necessary.
• When buckling persists, remove and replace the affected underlayment and shingles.

Ponding water is defined as water, which remains on a roof 48 hours or longer. It may result from rain, melting snow/ice or
runoff from rooftop equipment. The Asphalt Roofing Manufacturers Association is joined by many reputable organizations, such
as the National Roofing Contractors Association, the Midwest Roofing Contractors Association, the American Institute of
Architects, and the International Institute of Building Enclosure Consultants in recommending that roof designs provide
adequate slope (usually min. ¼” per foot) to ensure that the roof drains freely throughout the life of the building, thereby
lessening the potential adverse effects of ponding water.
If not addressed, ponding water may result in significant consequences including but not limited to:
 Deflection/Deformation: As water accumulates in ponding areas, the load on the roof increases, and may result in deck
deflection. The potential for deck deflection increases with the capacity of the area to hold water thereby increasing
the potential risk to the structural integrity of the deck.
 Ice Damage: Ice formations develop and move constantly with changes in temperature. This movement may “scrub”
the roof membrane to an extent that physical damage to the membrane may occur.
 Biological Growth: When water stands for long periods of time, it promotes biological growth, such as algae and
vegetation. Damage to the roof membrane may occur from chemical and physical attack from the bio-growth as well
as the expansion and contraction of the bio-growth during wet and dry cycles. Additionally, vegetation and other
debris may clog drains and cause additional ponding.
 Dirt/Debris Accumulation: Accumulation of dirt and debris may support biological growth. If a ponding area dries, the
accumulated dirt and debris may contract during dehydration (resulting possibly in “alligator cracking”) and pull at the
surface of the membrane.
 Water Infiltration: If roof membrane integrity is compromised, the risk of water infiltration into the building and
subsequent interior damage is amplified.
Best practices to avoid ponding water are as follows:
 A roof’s structural frame or deck should be sloped, and drainage components such as roof drains and scuppers should
be included.
 Regular maintenance to ensure drains remain unobstructed so that ponding water does not occur due to clogged
drainage systems.
 If a deck does not provide the necessary slope to drain, a tapered insulation system may be used to create positive roof
drainage.
 Crickets installed upslope of rooftop equipment and saddles positioned along a low-point between drains, may help
minimize localized ponding in conjunction with a tapered insulation system.
 Rooftop HVAC condensate lines should be connected to proper drains to prevent condensate from draining onto the
roof.
If ponding water does occur, efforts should be taken to eliminate or reduce the accumulation and persistence of water on the
Effects of Ponding Water
on Low Slope
Roof Systems
2 of 2 A member service provided by the Asphalt Roofing Manufacturers Association Revised August 2019
roof surface. Failing to address ponding water may shorten the effective life of the roof membrane system.
To obtain specific information regarding the effects of ponding water on particular products and systems, contact the individual
roofing material manufacturer.

Self-adhesive (SA) modified bituminous membranes provide an effective finished roof when properly
installed. These systems combine the long-term, proven performance of modified bitumen sheet
materials with installation advantages imparted by a self-adhesive bituminous layer.
Product Description, Manufacturing Process and Governing Standards
Self-adhesive modified bituminous membranes are comprised of asphalt, polymers, and tackifiers, and
may contain mineral stabilizers. The products may be reinforced with fiberglass, polyester, or a
combination of the two. Products designed for exposure to the elements are typically surfaced with
mineral granules, coatings, films, or other opaque surfacing. The self-adhesive layer is protected with a
release film or paper, which is removed during installation.
Labor saving application without the added complications of torching, mopping, or liquid adhesives is
one of the primary advantages of self-adhesive membranes. Because there are no kettles or torches
required, installation of self-adhesive membranes may be less disruptive to building occupants.
Many self–adhesive modified bituminous membranes are evaluated using test methods in ASTM
D5147, as are other modified bituminous sheet materials, and may meet the physical properties of
asphalt base sheets or modified bitumen sheet material standards such as ASTM D4601, ASTM D1970,
ASTM D6162, ASTM D6163, ASTM D6164, and CSA A123.23.
Product Storage Prior to Use
Self-adhesive modified bituminous membranes are generally packaged and stored in cardboard boxes or
they are protected with opaque wrapping. Unprotected self-adhesive products should not be stored in
direct sunlight since exposure to ultraviolet (UV) rays may affect the adhesive properties, especially on
the outer convolutions of the roll, or cause “dog-legging” of the roll. Storage for extended periods or
under extreme conditions can alter the adhesion properties of the self-adhesive bitumen or affect roll
alignment.
Installation
The following items should be considered when installing a self-adhesive membrane system.
 Always consult manufacturer’s application recommendations before specifying or installing a
particular product.
 At the time of installation, the air, product, and substrate temperatures should be at or above
the minimum application temperature recommended by the manufacturer. While the typical
minimum temperature range for application is 40-50°F, consult the specific manufacturer for
recommendations for material storage and handling during colder weather application. Selfadhesive products should only be applied to an acceptable substrate, as specified by the
product manufacturer. The substrate must be free of dust, dirt, oils, moisture or debris that
could interfere with proper adhesion.
 Manufacturers may require the substrate be primed prior to membrane application to aid
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adhesion of self- adhesive membranes. Primers are applied by brush, roller, or spray. Check
with the manufacturer to determine requirements for primer type, application rate, and drying
time. Solvent-based primers may damage the self-adhered membrane and roof system if the
solvent had not evaporated fully before the installation of the roof system.
 Unlike other installation methods for modified bitumen membranes, there is no liquid
bituminous layer to fill all the surface irregularities. Consequently, proper application is
essential, especially at all overlaps and T- joints. Applying pressure to the sheet with a heavy
roller is typically required. End laps on mineral-surfaced self-adhesive sheets may need to be
heat welded or sealed with compatible roofing mastics as specified by the manufacturer. If
using solvent-based mastic, following manufacturer recommended application rates and other
precautions to prevent solvent-induced damage to the membrane.
Where different grades of self-adhesive products and/or primers are available for cold weather
application refer to the manufacturer’s written instructions for guidance on proper product selection.
For more information, please consult the ARMA Modified Bitumen Design Guide for Building Owners.
The Design Guide addresses relevant aspects, issues and concerns of modified bituminous roofing
systems and their associated components, substrates, construction techniques and innovative uses.