Could Your Roof Use a Coating?

WHY YOUR ROOF MIGHT BENEFIT FROM EXTRA LAYERS

as early as the completion of the brand-new roof – is becoming increasingly popular, Mellott adds. The coating protects the new roof from damage from the start and adds reflectivity that the roof system underneath may not have.

Changing the color: This typically takes the form of a light-colored coating on a dark roof, says Graham. Coatings with high reflectivity don’t allow the roof to get as hot as non-reflective colors do, which can take the edge off of air conditioning costs and make the building more comfortable. The actual energy savings from cool roofs are under debate, but older roofs that are dark-colored and poorly insulated stand to benefit the most from a reflective coating, explains Hoff.

“One other factor can significantly change with a cool roof coating, and that’s if the building owner is paying for electricity with a combination of standard net charges and peak demand charges,” Hoff says. “A lot of utilities have additional charges based on the peak level of electricity that you use. In many buildings, the peak level will occur in the mid- to late afternoon and it will be related to cooling costs. You have an opportunity for more savings if you’re paying for peak demand charges and you lower demand.”

IS YOUR ROOF A COATING CANDIDATE?

Determine whether a coating is a good fit for your roof by first examining the condition, Graham recommends: “The roof has to be in relatively good shape or be repairable prior to the coating installation. One trap that building owners get caught in is that they try

THE ENERGY
MANAGER

to put a coating on the building when the
roof is too far gone. The key is to coat the
roof as a preventive measure rather than ‘I’m
having a roofing problem and need to do
restoration work.’”
Look for areas where ponding water col-
lects as ponding conditions are tough on
coatings, Hoff suggests. You’ll also need to
clean the roof before the coating is applied,
so make sure that whatever is on the roof is
removable. Understanding typical accumula-
tion on your roof will also help you deter-
mine what kind of coating your roof needs.

“Examine the environment of the roof. If
there’s going to be a lot of ponding water,
you may decide to go with a certain type
of coating. If it’s going to be exposed to
chemicals, debris or emissions from outside
or around the building, you may consider
different durable
solutions,” explains
Mellott. “You can
also look at the
dynamics – whether
you’re worried
about thermal
expansion and con-
traction and wheth-
er you need flex-
ibility. There’s a lot
beyond reflectivity
that helps buyers
Roofing professionals will help you match
the substrate you have to a compatible coat-
ing, as well as determine whether your roof
needs any repairs before applying the coat-
ing, Mellott adds.

GET YOUR ROOF READY

Your roof has to be clean and dry before
any coating system is applied. Follow the
manufacturer’s instructions for your coating
to determine how best to prepare the roof
surface. “You can’t paint dirt,” Mellott adds.
“Some people clean it and don’t dry it, and
they end up with pimples in the coating.”
Most coating systems involve a two-coat
process that starts with a primer, Hoff notes,
so apply the recommended primer for your
roof type. This ensures that the top coating
adheres to the substrate correctly. The manu-
facturer may also specify certain flashing and
detailing techniques to finish the installation.
Make sure the installers are following the
directions to the letter to ensure that your
warranty remains intact.

“It’s more sophisticated than painting a wall,” Mellott says. “Make sure you’ve got properly trained installers.”

Janelle Penny janelle.penny@buildings.com is Senior Editor of BUILDINGS.

Coating systems are more than just a light-colored layer over your roof – they can reflect sun- light, protect the underlying roof system from the elements and even lower your energy demand.

Choosing a cold-applied product in particular can also allow for savings on labor since the contractor doesn’t need to deal with bitumen feeding equipment or other tools for hot-applied systems, explains Mark Graham, Vice President of Technical Services for the National Roofing Contractors Association (NRCA). Many cold-applied coatings can be applied straight out of the container with a roller, brush or sprayer.

Could a cold-applied roof coating be a good fit for your building?

WHEN COATINGS MAKE SENSE

Coatings can be applied to nearly every type of roof, save for those covered in gravel or other ballast, notes Dr. James Hoff, President of TEGNOS Research. Building owners usually opt for roof coatings based on one of three main reasons.

Restoring an aging roof: “If a roof has been exposed for 10 to 15 years and a coating can extend the life by 10 or 15 more years, customers will consider applying a coating system rather than putting a whole new roof on,” explains Joe Mellott, Vice President of Imetco and Former President of the Roof Coatings Manufacturers Association (RCMA). “It’s a very sustainable way of man-