Helping Architects Take a “Whole Window”
Approach to Specs
With all the improvements being made in glass performance
today, it can be easy to forget that the design and installation of framing
can make or break the performance of a window or curtainwall system. After
all, it’s through the framing connections that water and air can leak
into a building, and the frame’s thermal conductivity is as integral a
part of the unit’s thermal performance as the glass is.
“There’s a definite connection between the two—the glass helps the framing
system too,” says Walt Lutzke, marketing coordinator of Tubelite Inc.
in Walker, Mich.
Gary Taylor, marketing manager of the commercial products group of U.S.
Aluminum in Waxahachie, Texas, elaborates, “The use of a proper framing
system will improve the energy efficiency of the whole system, including
the glass being used. The key to energy efficiency is thermally broken
framing, installed properly, in an opening designed to accept the type
of framing required to meet the surrounding conditions, using the correct
glass make-up to achieve a desired U-value.”
Taylor adds, “Any system used, if not installed properly, can de-value
the efficiency of the whole system.”
Greg Koch, sales manager for REHAU in Leesburg, Va., says that one of
the challenges architects face when it comes to commercial door and window
framing systems is that they simply aren’t aware of all of the new options
“I think that one of the challenges we have is to demonstrate to architects
and the industry as a whole that we’ve moved beyond the late ‘60s, early
‘70s technology in glazing systems—basically, aluminum—and in trying to
figure out how aluminum performance can be improved by adding thermal
breaks, thermal slots, etc. There have been so many ways used in trying
to improve the performance of aluminum,” Koch says.
As suppliers and glaziers alike know well, architects have to look for
aesthetics as well as performance in the products they specify. Frames
are one area where the architect can be unique, as Lutzke points out.
“Simple things help customize the project so it looks a little more unique—maybe
a different profile for the face cap, or a new color of some kind,” he
Koch agrees that unique color is one option requested time and again,
a request that he says has been an issue with PVC products, such as the
curtainwall his company manufacturers, in the past.
“One of the challenges that’s always been associated with PVC is color
options. You can create colors by laminating a high-performance film or
adding paint to the surface of the PVC and there are systems that have
been engineered to have success with that. But, again it’s something new
and different and convincing everyone these are good options is a challenge,”
Taylor, too, sees painted framing as a frequent request—particularly requests
for custom colors—as well as minimal sightlines and larger spans. He also
says architects and the owners they serve are, quite simply, “looking
for a clean, durable, energy-efficient product that accents the whole
building and allows as much visible light into the building without obstructing
What Architects Need to Know
When it comes to education for architects, these suppliers see a number
of common errors come up time and again—errors that glaziers and fabricators
should be aware of before they happen.
“The biggest [error] we see is knowing when to use curtainwall versus
a storefront,” Lutzke says. “Even if the material is on the ground floor
of a building it may be taller than the storefront product is designed
“I wish that they knew that it existed,” Koch quips of the product his
company offers. He adds in seriousness that this is, in fact, an issue—many
designers may not look to the materials used in Europe as a basis for
design. In reality, Europe has faced the energy costs that now are driving
glazing trends in North America for many years.
“They’ve been faced with these energy costs for decades now and they needed
to find a solution,” Koch says. He adds, “It’s an educational thing.”
In addition to awareness of the products available, Taylor says, “I would
like to see architects consult with the system vendors when designing
a project. A lot of designs miss a few pertinent issues” (see Tips for
Proper Specs below).
Tips for Proper Specs
Gary Taylor, marketing manager of the commercial products group of United
States Aluminum in Waxahachie, Texas, points to a few issues that he says
designers frequently miss when it comes to properly specifying framing:
• The surrounding substrate may not be designed to handle the load or
depth of a system required to meet the criteria.
• The way that a system is glazed during new construction does not always
account for ease of glass replacement in the future. Taylor says he sees
“inside set” systems that have a wall, cabinetry or some other obstacle
installed in front of the framing, making it a “remodel” project should
the glass need to be replaced.
• Expansion joints should never be under the threshold of entry doors,
Taylor says. “Architects should design the building slab to continue past
where the entry doors are to be set. The installer needs to have enough
substrate (concrete) that his anchors will not ‘blow out’ when installed.
The expansion joint needs to be far enough away from the threshold so
as not to affect the operation of the door(s) due to heaving from freezing
• Caulking to EIFS needs to be done before the top coats are applied,
otherwise proper adhesion will not occur, thus causing the window system
to leak. “This, unfortunately, ends up falling back on the glazier and
window manufacturer with the reasoning that their system is failing to
stop water penetration,” Taylor says.
• Taylor points out that “realistic designs that are achievable” can be
created with the input of a vendor’s representative. “This input will
help to keep the job from stalling during the construction phase while
a desired effect is being worked out,” he adds.
• Architects specifying custom-painted or -extruded systems should realize
the time constraints of this design and make sure that it will work in
the timeline by which the owner would like to have their building completed.
• Proper anchoring is paramount to preventing system failures. Taylor
says, “Too many times I have seen storefront framing installed in 16-gauge
metal studs without any blocking in the studs. There is usually a push,
back and forth, between the general contractor and the glazier, as to
whose responsibility it is to install that blocking. What I hear the most
is, ‘it’s not shown on the drawings.’ The general contractor tells the
contract glazier that it is their responsibility. The contract glazier
tells the general contractor that it is the framer’s responsibility. It
goes back and forth and becomes a major issue. A lot of times, blocking
never gets installed and thus, the system is installed improperly. This
ends up being a ‘time and material’ issue with regards to who is responsible,
and who is going to pay for it.”
Megan Headley is the editor of USGlass.
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