Condo Media - October 2019 - 58

The Region

MAINE

Black or
White?
Weighing New
Roofing Decisions
[by Jack Carr, P.E., RS, LEED-AP]

Some board members may think
deciding about a new roof surface
is over their head (forgive the pun).
Condominium board members and
property managers of urban mid- and
high-rise buildings often face flat roof
maintenance issues. And now a new
wrinkle in the roofing decision process
has arisen: black or white.
In the recent past, most flat
roofs were made with a rubber-like
elastomeric membrane called EPDM.
Though black EPDM still accounts for
the majority of flat membrane roofs
for condo, commercial, and industrial
buildings in the northern states, you
will see things are changing just by
looking out an airplane window as you
approach a major airport to see the
roof landscape below turning white.
Cool roofs are designed to reduce
energy consumption and reduce
what is commonly called the urban
heat island effect. Cool roofs are
categorized into three types: white,
reflective coated, or green (vegetated)
roofs. White roofs are the most
common with TPO (thermoplastic
polyolefin) and PVC (polyvinyl
chloride) being the typical choices.
Though PVC and TPO roofs have
the same wear and cost factors,
PVC materials have some negative
characteristics, such as high toxicity
and un-recyclability, so for ease of
comparing black to white, we will only

58

CONDOMEDIA October 2019

consider EPDM vs. TPO in
our comparison discussions.
COMPARING OPTIONS
To start with, TPO roof membranes are
recognized to have longer lives, lasting
an average of 25 years, compared to
EPDM lasting 20 years. This is in some
part due to TPO's resistance to UV
and thermal expansion damage.
Some TPO products developed bad
reputations in the past due to their
inability to handle severe cold, which,
in some cases, caused the membrane
to shatter. These problems are reported
to have been eliminated with today's
TPO roofing materials.
Secondly, the initial cost favors
EPDM roofs. However, when life cycle
and energy cost issues are considered
the black and white roofs become
competitive. Installation methods
differ in that EPDM seams are taped
or adhesively sealed while TPO seams
are welded by a thermal process.
There are strong forces pushing
the general acceptance of white roofs
in the future. States such as California
passed laws in 2005 requiring the
use of reflective roofing materials,
as well as individual cities such as

Chicago establishing building codes
to favor its use. There is a body of
evidence developing that shows the
heat island effect of black surfaces,
which include not just roofs but also
parking lots, paved roads, and building
facades can have an impact on local
weather characteristics.
RATING SYSTEMS
The nation's largest green building
advocates are influencing architects
and building owners by favorably
rating buildings with cool roofs.
Under the joint program of the US
Environmental Protection Agency
(EPA) and Department of Energy
(DOE), for a roofing product to receive
an Energy Star label under its Roof
Product Program, it must have a solar
reflectivity of at least 0.65 and weathered
reflectance of at least 0.50 in accordance
with EPA testing procedures.
The Cool Roof Rating Council (CRRC)
created a rating system for measuring
and reporting the solar reflectance
and thermal emittance of 850 roofing
products and provides this to energy
service providers, building code bodies,
architects and specifiers, property
owners, and community planners.
Condo Media - October 2019

Table of Contents for the Digital Edition of Condo Media - October 2019
