TYPES OF PAINT PROCESSES
Field vs. Factory Painting
Most metal roofs are painted,
and there are different processes for painting the metal roofing
material. Field painting is one option, yet it is inefficient
and lacks the quality found in factory-painted metals. Furthermore,
field painting is an extremely expensive process and has a life
expectancy of only five to seven years. Therefore, it is only
used in exceptional circumstances or where damage has occurred.
On the other hand, factory painting
produces a much higher quality finish that is typically warranted
against chipping, peeling, fading, and chalking for various periods
of time.
Giant rolls of flat metal in the factory
receive a number of different layers of treatment. The initial
coating is metallic -- either zinc, aluminum, or zinc-aluminum.
This covering is applied to both the top side and the underside
of the metal. The second layer, also applied on both sides of
the metal, is the primer. The final layer is a base coat, applied
to the underside of the sheet, and a premium paint or a granular
coating for the top side. Through technology, the painting process
can provide an even thickness, as well as a superior paint finish
for a much more economical price.
Paint Resins
The production of metal roofs uses one of the three most common
resins for panel paints: polyester and silicone resins (silicone-modified
polymers - SMP), or fluoropolymers.
Polyester resins are widely used because
of their relatively low cost. They have high gloss when applied,
but will lose their glossiness over time. It is important to
note that their color vibrance will diminish within five years.
SMP resins are different blends of polyester
and silicone additives. These resins improve the performance
properties of resins, are available in a variety of gloss levels,
and will last longer than polyesters.
Fluoropolymers are technologically advanced
and consist of a fluorinated polymer that contains unbeatable
thermal-, chemical-, and UV-resistant properties. These resins
have a high resistance to dirt retention and environmental aging,
and are virtually maintenance free.
Kynar 500 and Hylar 5000 are trade names
for a specific resin that uses a fluorocarbon compound. These
resins have a medium-to-low gloss that resembles a teflon-like
coating. They maintain color retention, repel dirt, and provide
superior UV-light protection. The best protection level of Kynar
and Hylar is a 70-percent formulation to ensure a longer life
span. (One must specify them by name.)
ADVANTAGES OF METAL ROOFING
Standing-seam steel roofing holds the
largest percentage of residential metal roofing in the industry.
This type of roof is economical, attractive, and used in heavy
snow areas. With a historical look that is gaining new popularity,
standing seam is the oldest style of metal roofing that can be
seen on traditional and restored buildings and homes.
In addition, the latest styles of metal
roofs are catching the eye of many homeowners. The new metal-roofing
products address all preferences by providing a variety of designs,
styles, and colors to complement any type of architecture. As
there are many advantages to standing-seam steel roofing, many
of these attributes can be found with other recent styles of
metal roofing.
Metal roofs are durable, offering a
high-strength-to-low-weight ratio. These roofing systems are
almost maintenance-free, no cleaning or pressure washing is needed,
and will not lose impact resistance with age. Furthermore, metal
roofs are low weight and can be installed over many existing roofs.
The advantages of a metal roof in severe
weather are numerous. Metal roofs are fire retardant, providing
a unfriendly home to fire-blown embers. In heavy snowstorms,
metal roofs reflect radiant heat to melt ice and snow. In high
winds, standing seam's fully interlocking panels can pass the
Dade County, Fla., test -- withstanding winds over 110 miles
per hour.
There are numerous environmental benefits
of standing-seam metal roofs. Metal roofs are energy efficient;
the metal reflects the heat and blocks heat transfer. Homeowners
have reported a savings of up to 20% in their energy bills. Furthermore,
steel roofs are made from 60-65% recyclable material and can
be installed over existing roofs, eliminating excessive landfill
disposal.
Standing-seam steel roofing is a complete
system that includes factory- formed sheets and accessories,
consistent protective finish, and overall protection. A metal
roof is actually quiet, despite the misconception that they are
noisy. Folds in the metal, solid decking, and insulation in the
attic or ceiling muffle the sound of rain.
Cost Issues
While the initial cost for a premium metal roof is higher than
most other roofing materials, the investment homeowners make
for installing a metal roof will be returned over many years.
Installation Considerations
Many metal-roofing manufacturers have been reviewing the installation
process and looking for ways to make it simpler and less labor
intensive. Some metal manufacturers have been able to design
a roofing system that needs only six common tools.
Furthermore, metal-roofing manufacturers
have been designing products that do not require specialized
training. Contractors can learn how to install a metal-roofing
product through a brief presentation by the manufacturer or through
a step-by-step video.
Future of Metal Roofing
Metal roofing will always be a roofing option, for both old and
new homes and buildings. In the past few decades, metal roofing
has evolved into a variety of styles and designs while maintaining
its traditional standing-seam style. Even though standing seam
still dominates the metal-roofing industry, other varieties and
styles have also emerged, attracting many different audiences.
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