By Amy Stokes
More than any other roof system,
standing-seam metal requires unique details to maintain its structural
integrity and provide a lifetime of watertight protection.
Experienced metal roofing
contractors know that a roof system which is properly detailed by the
manufacturer will not only perform as designed, but can significantly
reduce labor costs and protect both the installer and designer from
potential liability.
Manufacturer-Supplied
Details
Properly engineered and installed details are absolutely crucial to
metal roof system performance. While most roofing system manufacturers
do offer standard boiler-plate details to designers, it is imperative
to
provide
customized
details engineered for each project, as well as
thorough step-by-step installation guidelines. It’s simply not
realistic
to expect the installer’s roofing crew to understand thermal expansion
coefficients, modulus of elasticity, and internal strain forces.
A
comprehensive
shop drawing package
prepared by the manufacturer is the
most effective way to ensure optimum product performance and proper
installation, and to reduce potential liability for design
professionals, installers and building owners.
Any standing seam roof can include a wide variety installation
conditions, as well as a wide variety of detailing methods to address
them. To help you understand how specific details affect overall
system
performance, let’s take a closer look at an example - the
Series
300 Expanding Eave.
Look for more Featured Details in future
issues of the
Spotlight.
To Cleat or Not To Cleat
Some metal roofing professionals believe that a
hemmed cleat is required at the eave to inhibit water infiltration.
However, a cleat can inhibit the natural expansion and contraction of
metal
if there is not enough room left for movement. Proper cleat
positioning
is necessary for maintaining adequate clearances to allow the natural
expansion and contraction of the metal.
Requiring a cleat, and its proper placement, leaves the
responsibility for system performance completely with the contractor,
rather than with the manufacturer. It requires the installer to fully
understand the ambient temperature on the day of installation. If
panels
are installed on a 100-degree hot August day, the installer must leave
enough room for “shrinkage” so that when temperatures drop in cold
winter months, the system can accommodate the panel contraction
without
failure.
Expanding
Eave
A properly engineered Expanding Eave, on the
other hand, provides total
watertight protection while allowing unlimited thermal movement.
IMETCO’s
Series 300
expanding eave, for example, allows panels to
“float” as needed to accommodate their natural movement. It also
provides three lines of defense against water infiltration:
Take a closer look at the Series 300 Expanding
Eave:
Be sure to watch
for more featured details
in future issues of the
Standing Seam Spotlight.
To request information about additional Series
300 details, or to schedule an accredited on-site presentation, click
here to contact
your IMETCO representative.
Be sure to ask about all of IMETCO's high-performance
metal edge, roofing and
wall systems.
