Architects' Guide to Glass
All the Right Pieces
Customized Systems Play Key Role in Atlanta
by Ellen Rogers
Imagine spending hours upon hours putting together a puzzle
only to find that one little piece is missing—a critical component that
would bring the whole thing together. Bringing all of the pieces and parts
in place to form Atlanta’s 12th and Midtown development was a lot like
putting a puzzle together—if one component had been missing the project
may not have been completed as it stands today. All of the building materials
had to work together, as did everyone on the design and construction teams—each
played a unique role, and when they all came together it resulted in the
successful completion of the project.
“A remarkable puzzle was put together with all these pieces and parts
… that made the economics work, the aesthetics work, and it structurally
worked,” says Rob Rule, a partner with Atlanta architectural firm Rule
Joy Trammell + Rubio (RJT+R).
Situated along the city’s “Midtown Mile,” 12th and Midtown is a 2.5-million-square-foot,
mixed-used development that includes office towers, hotels, condominiums,
retail and restaurants. Consisting of several components, the tower known
as 1010 Midtown (1010) stands 35-stories tall and includes more than 400
condos and 50,000 square feet of retail and dining space. A second tower,
located at 1075 Peachtree Street (1075), consists of 725,000 square feet
of office space, 60,000 square feet of retail space, a 400-room hotel
and 100 residences. The use of customized glazing systems was key to creating
distinctive architectural details in both towers.
“1010 has a very distinctive sculptural glass design, including a [curved
wall] facing Peachtree Street,” says Rule. “We decided early on that 1010
should be an all-glass structure and its design strength would come from
its 3-dimensioanality that resulted from the balconies and the floor-to-ceiling
glass. When we started looking at different glass types we decided to
relate it to a project that we had done previously with Daniels Corp.
[project developers] called Plaza Midtown. That glass had nice coloration,
good light transmittance, was not too reflective, not too clear and using
it again would start to establish a [brand identity] for the developer.”
Like 1010, 1075 also has a strong sculptural form.
“It has a pleated trough that comes out of the building and we knew it,
too, would have to be distinctive,” says Rule. “We debated whether it
should be more of a stone or pre-cast building, but in the end we decided
to go with glass, though it does have stone within the spandrel.” While
both 1010 and 1075 include glass supplied by Viracon, Rule says for 1075
they decided to use the company’s VRE 137 instead of the VRE6-54 used
on 1010. “We liked the blue-gray color as it was a slight contrast to
the blue-green used on 1010,” says Rule. “It had good visible transmittance
from the interior and was very clear looking out; it’s not reflective,
but had a comfortable amount of tint to it that was very natural so you
could still see in. It also had a good solar heat gain coefficient.”
In addition to the glass, the window wall and curtainwall systems were
also important elements and required upfront design approval meetings.
“We sat down with the architect early on to get system approval and then
we did shop drawings based on that profile approval,” says Frank McCoy,
vice president of Glass Systems, contract glazier for the project. “On
1010 there is about 220,000 square feet of custom window wall and on 1075
there is 185,000 square feet of custom window wall. On 1010 we have about
11,000 lites of glass; on 1075 we have 8,000 lites of glass. On a condo
you have a custom sliding glass door and on 1075 there are about 150 of
these custom sliding glass doors; 1010 has about 400.”
McCoy adds “Sliding glass doors drive these projects. The lead-time on
them is long—they have to be ordered before we order the window wall and
we do a separate shop drawing on the sliding glass doors themselves,”
says McCoy. “That’s why we don’t use standard curtainwall; it does not
work with sliding glass doors.”
YKK AP supplied the metal systems. And while the systems were not 100-percent
brand new, they were customized for this project.
“Both 1010 and 1075 utilized systems that our company has used on other
condo, mixed-used type projects,” says John McGill, regional business
manager, project business group, for YKK AP. “Where we had the most involvement
was in how we customized [the materials] for these projects and how we
incorporated multiple systems into the same project and could still achieve
the desired look.” For instance, two different window wall systems were
used—a 5-inch and a 6-inch depth system. “Those varied mainly due to structural
requirements as there were different parts of the building where the floors
would be larger in height so those areas needed a stronger system,” says
In addition to the window wall, several floors incorporate curtainwall.
This meant a smooth transition between the curtainwall on one floor and
window wall on the next would be necessary. To do so, a slab edge cover
concept was used.
“A lot of custom detailing went into that because while we are using the
two systems from floor to floor, these were not straight lines,” says
Luther Hudson, president of Glass Systems. “There are radii involved and
multiple odd-degreed corners that we had to turn and shape.”
McCoy says curtainwall had to be used on some of the 1010 floors because
the window wall would not meet load requirements. There are a lot of shear
walls on 1075, which are poured-in-place concrete walls that are structurally
sound and required spandrel glass.
McGill says incorporating different systems into the project and customizing
them to the specific needs without the expense of designing something
totally custom was significant.
“I think if you’re starting from scratch and you’re doing something totally
new, there are a lot of upfront expenses and lot more testing that must
be done,” says McGill.
One of the most unique characteristics of 1010 is a serpentine glass wall
that follows the curve of Peachtree Street. The segmented wall goes from
concave to convex and does not have any 90-degree angles.
“It’s a fairly tight curve so we wanted to have a module in the vertical
mullion system that would allow for straight pieces of glass,” says Rule.
“While you can bend glass to create curves … we knew we needed to go in
there with a design that would use straight glass. This required us to
carefully balance the spacing of the mullions with straight segments of
glass to create a building that feels like it has a smooth curve over
the convex and concave portions without looking segmented.”
McGill agrees that the spacing of the mullions was an important consideration.
All for One
With so many unique considerations, open communication and synergistic
working relationships between all the groups involved was key. In this
case, RJT+R, Glass Systems and YKK AP had all worked together on previous
projects so everyone already knew what to expect from each other from
“This project had the exact same requirements in terms of systems and
profiles as what we did on the Plaza Midtown project,” says Hudson. “So
we had a natural tie-in with the architect, YKK, the contractor and the
Having everyone based in Atlanta was also a plus.
“Being able to work closely with the architect and contract glazier was
important,” McGill says. “A team approach makes the chances of success
that much greater.” AG
Ellen Rogers is the editor of the Architects’ Guide
to Glass and Metal.
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