Let the Sun Shine In
Perforated metal gives designers plenty of options for
Perforated metal offers architects many options and benefits as
a sunshade. The hole size and pattern can change how much light is
let through, and how much can be seen through the design element.
With the option of being used in both horizontal and vertical
formats, or as a screenwall, perforated metal sunshades provide a
unique look for buildings and parking garages.
"Perforated metal offers great flexibility in design, color and
performance with low-maintenance, cost-effective solutions," says
Steve Kotecki, marketing at Hendrick Manufacturing, Elgin, Ill.
Shawn Bowman, CSI, national director of sales and marketing at
Architectural Metal Solutions Inc., Alsip, Ill., says the
beauty of any of perforated metal is in its versatility.
"Perforated metals come in hundreds of patterns or can have custom
patterns," he explains. "In addition, perforated sunshades and
panel systems can be formed, rolled and machined, allowing the
design not only to be perforated, but to be three-dimensional as
"The flexibility to custom design a shading system based
on solar orientation, desire for varied levels of transparency or
opacity, and any desired aesthetic in terms of pattern or relief,
shade and shadow, is easily accomplished with perforated metal,"
says Mark Kranz, FAIA, vice president, design director at SmithGroupJJR, Phoenix. "We constantly
experiment with new and untested approaches, materials, profiles
and this allows us to keep learning. Most of the time, the end
product offers some element of surprise that you can take with you
to the next project."
Hole Size and
In perforated metal, the size of the holes and the pattern
create an open area, which is commonly expressed as a percentage.
"The greater the open area, the more light will get through,"
explains Kotecki. "The adverse happens with a lower open area."
The ability to manipulate transparency and opacity by varying
hole size, pattern and density gives architects the opportunity to
calibrate the level of light penetration and shading performance in
a very predictable way. Mike Griffith, marketing manager at Kovach Building
Enclosures, Chandler, Ariz., says they've done perforated
patterns as small as 1/8- inch holes, which doesn't let a lot of
light through. If the holes are kept closer together, Griffith says
the further you are from a building, the more it gives the
appearance of a solid louver.
"I'm always surprised by how transparent a seemingly opaque
perforated wall, screen or scrim becomes when viewing from the
inside of a building out," Kranz adds.
Additionally, Griffith notes that as a shade on parking garages,
perforated metal also acts as a natural exhaust system. "What
perforated metal achieves is enough sunlight to make it comfortable
inside, but it also provides ventilation," he explains. "There are
code requirements in parking garages if they're not vented
internally with a duct system, so you have to have enough natural
air movement to clear out the exhaust."
Panel Material and
To support the desired sunshade design, the correct panel
thickness is required. "The hole pattern chosen combined with the
material of the panel will usually dictate the thickness of the
material needed," Bowman says. "Bent or formed shapes can affect
the thickness required to meet a design intent as well."
Griffith says aluminum is the go-to material in their experience
because of its strength-to-weight ratio, while Kotecki says the
majority are manufactured in various grades of aluminum or
stainless steel. "The aluminum products finishes can be supplied in
all ranges of RAL colors for 70 percent PVDF powders and liquids
along with Class I anodizing," Kotecki says. "The stainless steel
products can be supplied with mechanical brushed finishes."
Choosing the right material gauge is critical in designing
perforated metal sunshades. "Even a thick steel plate that is
perforated can show up on the job site with too much waviness and
or imperfections," Kranz says. "We've found that when working with
sheet material, that providing structural stability through
breaking and bending creates relief and shadow while also
eliminating oil canning and deflection that is
The type of material and its thickness also directly relate to
its structural performance, corrosion resistance and warranty.
Bowman says thinner gauge material can be framed to give it
structure, while thicker materials can be frameless. "When the
choice is made to utilize perforated material in a design the
choices can sometimes be overwhelming," Bowman says. "We see
architects and designers incorporate any of hundreds of standard
perforated patterns or choose to create their own design
Expanded Metals and Sunshades
In addition to perforated metal, expanded metal is also a good
option for sunshades. According to the National Association of
Architectural Metal Manufacturers (NAAMM), its Expanded Metal
Manufacturers Association (EMMA) has completed testing for the
effectiveness of expanded metal used as a sunshade for windows and
The testing showed that expanded metal is effective as a
sunshade. The Solar Heat Gain Coefficient (SHGC) varies from 0 to
1, with the lower coefficient value indicating a more effective
shade. The EMMA tests show that at a maximum sun angle of 60
degrees, the SHGC varied from 0.09 to 0.14. Three different
expanded metal materials were tested with minor variations between
the materials. The SHGC varied from 0.1 to 0.5 through the full
range of sun angles for all tests. Testing was done in the 48-inch
Solar Calorimeter ICN #62060 by Intertek/Architectural Testing at
its Fresno, Calif., facility.
To obtain the complete test reports, go to naamm.org/division/4.
And, the size of the panel is typically determined by structural
performance rather than its ability to be manufactured. Ranges are
often figured on given wind loads, snow loads and spans, Kotecki
"The larger the panel, the fewer the connections and perhaps
reduced labor cost in fabrication," Kranz explains. "But the larger
the material, the higher the risk of deflection, visual waviness
and oil canning becomes. We've found that a collaborative
'design-assist' approach with the best industry subcontractors is
the most strategic approach to reducing risk, coming up with
something innovative, constructible, installable and
warrantee-able. It's always great when you can grow your technical
knowledge with someone who lives in that world every day. It
expands your perspective and opens up the potential to consider new
When it comes to designing perforated metal sunshades, Griffith
recommends bringing in the specialty contractor as early as
possible. "When we get the chance to really sit with the architect
and understand their design intent, perforated metal just gives us
a lot of options," he says. "There is a lot you can do with
perforated metal that is economical and attractive, and still gives
you the shade that you're looking for."
Working with a specialty contractor may also help you get the
most out of your perforated metal sunshades, as they are a very
energy-efficient building product and can help a project achieve
LEED credits. These credits can include EA Credit 1: Optimize
Energy Performance (up to 19 points); MR Credit 4: Recycled Content
(1-2 points); MR Credit 5: Regional Materials (1 to 2 LEED points);
and IEQ Credit 8.1: Daylight and Views Daylight (1 point).
*Photos courtesy of (from
top): Hendrick Manufacturing; DAMS Inc.-D.
Architectural Metal Solutions Inc.; Kovach Building