Drywall Project on the Leading Edge

The typical suburban shopping mall isn’t at the forefront of advant-grade design, but a retail mall just erected in suburban Vancouver, B.C., is anything by typical. For starters, no acres of parking surround the mall. Instead, the 380,000-square-foot, three story building abuts the street. Its parking is hidden in five levels behind the building. What’s more, rather than create a box-shaped building, Bing Thom Architects designed a glass-clad structure of sweeping curves.



The Aberdeen Centre may be a grand design gesture, but it was not an easy building to build. just ask drywall contractor Peter Gallagher, whose Vancouver firm, Gallagher Bros., was awarded the $3.3 million drywall contract for the usual building. Combine the complexities of the drywall work itself with a “very fast track schedule” (11 months starting in January 2003), which was four months
less than Gallagher would have liked for
the job, and the result is a contract rife
with challenge.



The drywaller completed it on time and
within budget, but not without racing
against the clock, tackling unusual and
arduous tasks along the way. Take the
walls and ceiling, for example. “The
only straight walls on the job were the
mall’s back corridors and the demising
walls in the retail stores,” Gallagher
points out. It made the installation of
columns, mouldings and bulkheads featuring
light troughs difficult.



“All the mall bulkheads and ceiling and
lines were curved. When it was done, we
actually only had two locations in a total
of about 20 feet where the radius of the
cove mouldings was wrong. We adjusted
the framing to suit the mouldings.”
The mouldings were produced by
Ontario-based Plasterform Inc. from
preformed fiberglass reinforced gypsum.



SEEING THE LIGHT




Many modern suburban shopping malls
feature skylights to maximize natural
light, but the Aberdeen Centre goes a
big step further. Not only does natural
light pour down through 17 conical skylights,
but it also rakes across interior
walls through the glazing that clads the
structure. That additional light meant
the drywall contractor’s fit and finish
had to be near perfect because imperfections would be highlighted by the abundant light.



Creating the detailing where the ceilings
meet the oval tapering skylights was partitularly challenging. Rounded or bull-nose
edges were specified by the architect.
“It’s a very nice detail, but it was
very tricky geometry because the sky-lights
are curving in plan, curving in section and tapering,” explains Luciano
Zago, project director, Bing Thorn
Architects.



Gallagher Bros. plastered the edges to achieve the bullnose. On the first two
skylights the contractor’s work received
mixed reviews from the architect. “They
didn’t get the kind of smoothness we
were looking for,” Zago explains, “but we
were quite happy with the last 15 sky-lights
they did.”



Gallagher devised a four-coat plaster surface
(with thicknesses of a quarter-inch
to a half-inch) to create the bullnose
edge. As the architect insisted on a
smooth, joint-free finish, the control
joints between the plaster and drywall
had to be small enough to be invisible
from the floor. Once the drywall and taping
were completed, a skim coat (brown
coat) made of a concrete powder gypsum-
based product was applied, followed
by three coats of drywall compound.
Two layers of quarter-inch drywall were
used because they could be bent around
radiuses of the skylights.



As difficult as the finishing work was, it
was just the warm-up act to the main
event: finishing the walls and convex ceil
ing of the 40,000 square foot upper promo court—a space designed to offer a
dazzling light and water fountain show.





NOBODY DOES IT BETTER



Imagine a 40,000-square-foot egg cut in
half, with the flat side facing up, suspended
from the ceiling. That is what the
convex ceiling of the promo court looks
like, Zago explains. “The idea was to
make it look like the ceiling was floating.”



To build the ceiling, Gallagher first had
to construct a substructure, then install
drywall and provide a finish as smooth
as a baby’s bottom. “We wanted a very
smooth finish because the natural light
that comes raking across the surface all
day (through the glass perimeter of the
ceiling) would highlight imperfections
in the finish,” points out Zago.



Overall, the architectural firm was satisfied
with Gallagher’s work, but the
architect says some finishing imperfections
are noticeable at different times of
the day. “It’s a three-dimensional curve
and it is a big surface. When you look at
it, it is quite remarkable. I guess we were
pushing them (Gallagher Bros.) to get
better.”



The architect was asking a lot. A baby “We’ve never done anything like this
smooth finish on a ceiling with so much before, and I don’t think there is any-unusual
detailing, curves and unusual thing like this ceiling anywhere on this
lines is, perhaps, a task impossible.
As a drywall contractor, we know you can’t
do that,” says Gallagher, who was
pleased with the results of his team of
drywall installers, finishers and framers.
“We’ve never done anything like this
before, and I don’t think there is anything
like this ceiling anywhere on this
scale.”



Mike Hartigan is project manager of
Dominion Construction Company
Inc., the construction manager of the
project. He concurs with Gallagher.
There might be some contractors that
could have matched Gallagher’s standards,
but none that could have bettered
Gallagher.



“Bing Thorn Architects is very creative
with concepts, but when it comes to
constructability they sometimes fall
short,” Hartigan adds. “They try to
offload the constructability onto the
general contractors, the managers and
the subtrades. It is a case of modern
technology not having caught up with
the ability of architects to be creative.”



Hartigan says the two biggest challenges
for Dominion Construction were the
“very aggressive building schedule” and
the actual construction of the complex
design. “It’s very artsy, very flowing.
Couple that with the fact that the construction
management contract meant
the design was ongoing while the work
was progressing, and you have a difficult
project. The owner (Fairchild Developments
Ltd.) carried a fairly hefty contingency
to cover for the ongoing aspects
of changes beyond the tendered package.”


DRYWALLING FRAMERS




Gallagher was given little information
on how to build the egg-shaped substructure.
“They (architect) didn’t give
us any dimensions or radiuses to follow.
All we had to work with was an outside
elevation point around the perimeter
and the lowest point of the belly of the
ceiling.”



The drywaller first did layouts on paper
of a grid pattern for the hanger suspension.
Using CAD, the architect then
plotted out elevation points. To create
precise curves, the ceiling was broken
down into lo-foot by lo-foot square
spaces. In each space were hundreds of
wire hangers, including one color-coded
wire pinpointing the elevation of the
space. “It gave installers a specific elevation
to work with, so they knew where
to place carrying channels. It’s how we
established the curves of the ceiling,”
Gallagher explains.



The suspended ceiling is made up of #9
hanger wire, 1.5-inch cold rolled steel
channel bar and 7/8-inch fir strapping.
At tight radiuses, a rolling bender was

used to bend the steel channel bars. “It
was interesting that a lot of our tradesmen
asked to be part of the framing
crew because it was such an unusual job.
They wanted to put their names to it,”
Gallagher says.



At tight radiuses, drywall installers
“pushed the limits” of bending the 4-
foot by 12-foot drywall sheets. The idea
was to minimize cuts and extra joints in
the ceiling that could be highlighted by
the abundant natural light. The design

specified a Level Five (skim coat) finish,
but the drywall contractor went further
by applying a four-coat system, similar
in composition to the application at the
skylights. Coats were applied perpendicular
to each other to eliminate rough
areas.



Reach for New Heights



About $200,000 worth of scaffolding
was required for the work, which was up
to 60 feet above the mall floor. The
problem was that the maze of scaffolding
obstructed sightlines of the job from
the floor. “The only time we really got
to see our finished product clearly from
the ground was after the ceiling was
painted,” explains Gallagher, noting it
was too late then to smooth any rough
spots.



Another challenge was installing the
acrylic stucco system soffits. They were
applied over Dens-Glas Gold wrapped
around the perimeter of the convex ceiling.
The idea was to give the effect that
the ceiling goes through the roof to the
exterior of the building.



Gallagher says during peak construction
a drywall crew of 68 to 75 men was
required for the fast-track job. About 20
of those workers were apprentices, ranging
from their first to fourth year. “We
gave access to every one of them different
aspects of the job,” he explains.



Just completed, the mall has already
picked up a nickname, the “urban
lantern,” because the glass-clad building
“glows” at night. “There are no solid
walls on the exterior,” points out architect
Zago, noting that the use of different
types of glass allows for varying levels
of translucency. “It’s become quite a
beacon for the owner.”



About the Author

Don Procter is a free-lance writer in
Ontario, Canada.

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