Innovations in Color and Texture

Expressive Capabilities for Architectural Surfaces
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Sponsored by Armourcoat Surface Finishes Inc., Lamin-Art and Trespa®
C.C. Sullivan

Exterior vs. Interior Surfaces

As with glass, opaque materials are variously suited to exterior duty or to only interior applications. The choice of color or texture must be vetted and specified carefully for its suitability to the demands of the selected use. "Considerations for color selection tend to be much more critical for exterior applications than for interior applications," says Trespa's Veraart. Examples of color specification for façades, roofs and other outdoor surfaces include:

  • Pigments with high resistance to UV exposure, as confirmed through recognized testing procedures.
  • Treatment or inherent resistance for chemicals or the corrosive effects of salt spray and salt fog, for example in coastal environments.
  • Graffiti resistance, which is a consideration for both interior and exterior product applications.
  • Level of texture for the surface — high-gloss may be a desirable design consideration or maintenance strategy, for example.

Veraart adds that interior wall applications and low-level exterior façades have a need for impact- and scratch-resistance due to close proximity to the public or to moving equipment. Since building occupants spend the most time indoors, color and texture are often given the most consideration there, both for aesthetics and wear. Fortunately, interior materials and systems generally offer designers a high degree of creativity, since the requirements for durability of pigments, dyes and textured elements relax significantly.

Two very different but equally successful projects offer valuable lessons. One is the new Montreal Concert Hall, a project for the provincial government in Quebec, Canada. Here, acoustics were critical to the specification, so the architects Diamond and Schmitt focused on surfaces "to reflect and refract low, medium and high frequencies," says principal Jack Diamond. "For low frequencies, there are large-scale convex forms — randomly placed, undulating walls and balcony fronts in this case — and for medium frequencies, molded plaster bands serve as smaller-scale surface variations." For the refraction of high-frequency sounds, however, Diamond's team employed wood paneling with varying textures, some very smooth while others are rough like sandpaper.

The Montreal Concert Hall, designed by Diamond+Schmitt Architects, uses colors and textures to highlight acoustical surfaces and improve their function. For medium frequencies, molded plaster bands in white offer small-scale surface variations and contrast to the wood paneling with various textures, which refracts high-frequency sounds.

Photo by Tom Arban

 

To create the smooth expanse of polished plaster for London's Natural History Museum, concrete was sprayed onto a mesh, followed by insulation and an EIFS basecoat. After adding a crack-resistant substrate and a lime-and-marble base, the ivory-colored plaster of hydrated lime, marble and concrete was finished by hand.

Photo by Stephen A. Wolfe

"Given the variety of nonsymmetrical forms, textures and other elements, a predominant material and a monochromatic color scheme has been employed to achieve design cohesion," Diamond notes. The floors and seat backs are all in wood, as are the walls, in a honey-colored Quebec beech; the upholstery is a pale wheat tone. "To avoid the muddy effect an overall monochrome can have, the horizontal plaster bands for mid-frequency reflection are in white, to provide a neutral reference for the eye and a freshness and lightness to the room," adds Diamond.

While even the most seasoned concertgoer may not realize the effect these forms and textures have on the acoustics, those who attend the hall's performances rate the overall quality very highly. Kent Nagano, conductor of the Montreal Symphony Orchestra, has crowed that the facility will take its place among the famed philharmonic halls of Europe.

In another cultural project, this time for a museum, the ancient art of plastering is appropriated for a contemporary gesture of massive scale. Known as "The Cocoon," the architectural form is a large egg-shaped volume, a new and unusual extension to the Natural History Museum, London. Officially called Darwin Centre Phase Two, the $120-million, freestanding installation was designed by Danish architecture firm C. F. Møller and finished by U.K. specialty contractor Armourcoat to resemble a literal cocoon—a silk bubble criss-crossed by threadlike textures.

To achieve the effect on the 213-foot-long, eight-story Cocoon, concrete was spray-applied to a form of expanded metal mesh on reinforcing bar to create a 10-inch structural wall. The contractor HBG Construction affixed polystyrene insulation to the curved walls with adhesive and mechanical fasteners on lengths of plywood, followed by an EIFS basecoat. This surface was surveyed to establish positions of 1-inch chases for control joints between 340 cast panels with special edge beads for a desired shadow gap and to allow thermal movement. A crack-resisting substrate was then applied, followed by a plaster substrate consisting of hydrated lime, marble and cement. The ivory-colored, polished plaster finish gives the Cocoon its signature color and texture.

While complex, the Cocoon's walls provide a highly engineered thermal mass and surface treatment to inhibit temperature variations inside, where laboratories and exhibits share space with a vast collection of 17 million insect specimens and 3 million plants collected over 300 years by Charles Darwin and other famed scientists.

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Originally published in Architectural Record
Originally published in October 2011

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