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By Sara Hart
Brownell and McCune’s subsequent
research suggests an emerging trend in specification: begin
at the end. Describe the aesthetic and functional attributes
required of the finished component and then work backwards
to find the best materials or combination of materials. After
evaluating several cementitious panels, the architects were
convinced that one of Transmaterial’s recombinant materials—Richlite—was
a good alternative. A panel made of layers of paper impregnated
with a phenolic binder, it’s tough, long-wearing, and
low-maintenance. The architects made it clear to the client
that this hardboard is environmentally friendly by virtue
of employing a low-VOC binder and paper from certified managed
forests. They also explained that its durability and low-maintenance
made it an excellent cladding material for Alley 24.
Specifying a material, however, is only
a small part of the process. For new materials to make it
from the catalog to the construction site, architects must
figure out how to detail them so that they are buildable and
their inherent attributes remain intact. In this case, the
architects decided to detail the hardboard as a rain screen
for several reasons, but one in particular—mold. Brownell
says that mold is a problem in the damp Seattle area, because
wall cavities are often too thin and trap moisture. They designed
a generous airspace behind the rain screen, which will allow
water vapor to exit the wall cavity, thus discouraging the
cultivation of a mold (see details on page 216).
NBBJ encourages the evaluation of the
key materials on a project, but Brownell admits that it takes
a great deal of time to study alternatives to time-tested
materials. It requires factory visits, engineering calculations,
mock-ups, multiple iterations of details, and even letters
to the building department regarding code compliance. Although
it is hard to assign the cost of this research, Brownell estimates
that it could add 5 to 10 percent to the design-development
and construction-document phases for those areas being studied.
Sometimes, though, clients see the value and the long-term
benefits of the additional costs, especially those who place
a priority on environmentally responsible development. Still,
paying extra for research is a long way from becoming the
norm.
On the other hand, it’s possible
that clients will begin to hire additional consultants to
provide their architects with material research for difficult
projects with exigent circumstances. In July 2003, Arup launched
an independent specialty—Arup Materials Consulting (arup.com).
Materials specialist Graham Gedge said then that this was
an opportunity for the international engineering firm to provide
“best-practice advice on the use of materials from design
to demolition, from steel and concrete to glass, stone, timber,
and new materials technologies.” If these and other experts
can guarantee minimization of risk, enhanced performance,
and added value, then we may see more innovation in design
and building sooner rather than later.
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