Sealants: The Magic Touch

Shingle Sealants Bond Your Roof Together
With ever increasing performance expectations for asphalt shingles designed to
withstand high winds and heavy rains, manufacturers have responded by producing
increasingly higher-performing shingles. When properly installed, asphalt shingles are
manufactured to bond securely to each other, forming an integrated roof-covering
system designed to protect your home from the elements.
What is the secret ingredient? Asphalt-based bonding
sealants create the tie that binds!
How Are Shingles Attached to the Roof Deck?
Asphalt shingles are manufactured as individual units and are installed in courses
along the roof. When properly installed, the shingles adhere to each other to form a
cohesive roof-covering. Initially, make sure that the wood deck is in good condition,
then, assure that the right underlayment material is properly attached to the roof
deck. The underlayment provides extra protection for roof decking materials, and
keeps the shingle materials from adhering directly to the deck over time.
Nails and the Roof Deck
The best way to ensure that asphalt shingles are properly attached is to follow the
manufacturer’s installation instructions. As each asphalt shingle course is laid out, roofing
nails secure the shingles to the roof deck. Here are a few nailing practices recommended by
many shingle manufacturers.
It is important to make sure shingles are attached to the deck by using the proper type, size
and quantity of nails. Make sure the nails are in the right place by driving them in the
indicated “nailing zone.” Always ensure that nails in laminated shingles are driven through
the double thickness overlap area as indicated in this diagram.
How Does the Sealant Work?
Once each course of asphalt shingles is attached to the roof deck, every subsequent
shingle course will bond with the previously installed course, with the asphalt-based
sealant fusing the shingles together. The bonding sealant is factory-applied on the
shingle (front or backside), so following the manufacturer’s instructions regarding
spacing and alignment are critical for a proper sealant bond. Heat and UV rays from the
sun activates and softens the sealant to create the necessary bond needed to provide
good wind resistance for the finished asphalt roof covering system. Once sealed, the
bond is designed to hold the asphalt shingles together as a complete system.
What Are Sealants?
An asphalt based, heat activated, viscous
bonding material formulated to retain
bonding strength in all weather conditions,
once initial bonding has occurred. Sealants
are used on asphalt shingles to bond the
individual unit shingles together.
The Importance of Proper Installation
Recent research conducted by the University of
Florida’s College of Engineering1 has concluded
that proper installation is an important and very
critical factor to ensure that the shingle sealant
bonds the shingles together as designed.
Industry performance standards for asphalt
shingles include testing of the sealant bond
under laboratory conditions. These tests are
intended to simulate the resistance of the shingle
to uplift forces created during wind events.
Selecting a shingle that meets or exceeds local
wind-speed requirements in the building code
will help your roof covering withstand
windstorms and protect your home. Asphalt
shingle design has to ensure compliance to everchanging building code requirements. Shingles
have always worked as an effective windresistant roof covering, and now, thanks to the
use of bonding sealants, they work even better to
keep out the elements.
1Masters, Forrest J. Ph.D., P.E. (FL) (2013). Phase II Report: Investigation of the Wind Resistance of
Asphalt Shingle Roof Coverings (SERRI Report 90100- 02). Florida: University of Florida.
How Can I Make Sure the Sealant Does its Job?
Be aware of these key elements…
• Local code requirements matter. Manufacturers test asphalt shingles to the
requirements of local building codes. Check with the manufacturer to verify the
shingle you select is appropriate for use in your area.
• Schedule your roofing project to consider weather conditions. Asphalt shingles
can be vulnerable to wind forces until the sealant bonds, so it may be best to
install your roof when the temperatures are well above freezing. Heat and UV rays
from the sun activate the sealant to bond the shingles together. Check to make
sure that severe weather, including heavy rain, dust storms, snow and high winds,
are not in the forecast.
• The manufacturer’s installation instructions are your guide to a properly-attached
asphalt shingle roofing system.
How Can I Make Sure the Sealant Does its Job?
• Proper sealing starts with proper nailing. Always follow the manufacturer’s
instructions and use the right fasteners for the job, and make sure the shingles are
properly placed. Be sure that the nails are placed within the prescribed nailing
zone and are driven flush with the top surface of the shingles as required by the
manufacturer.
• For more information about Florida Building Code Requirements for asphalt
shingles, click here to read the ARMA Technical Bulletin.
What about that mysterious little cellophane strip?
Asphalt shingles are packaged for shipping in bundles, so most
manufacturers apply a strip of material between the shingles to
keep them from adhering into one big shingle brick! Once the
shingles are separated, the strip is in an area that will have no
effect on the performance of the shingle.
It is not necessary or desirable to peel off those strips.