Wood Design + Construction jump page

Wood Design + Construction (Continued from p. 54 of the February 2009 issue of BD+C)

	Once you've read this special report, take the AIA Exam to earn 1 AIA HSW learning unit. (one-time registration required)
	Reed Business Information is a Registered Provider with the American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES Records for AIA members. Certificates of Completion for non-AIA members are available on request.        This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.

HOW TO INCORPORATE WOOD INTO CEILINGS
What’s unique about wood finishes for ceilings is that they can be given monolithic treatment. As 9Wood’s Roemen explains, while floors may be covered with rugs and walls may be interrupted by openings such as windows or doorways, ceilings can be as expansive as a canvas. That’s why Mark McInturff, FAIA, principal of McInturff Architects, Bethesda, Md., explains that, from an architectural point of view, “the ceiling is the easiest surface to work with to give a room character.”

McInturff, who has won several American Wood Council design awards in his 34 years as an architect, often uses wood elements to define or accent space. “Suspended wood panels can anchor the center of the room or define one edge of the room where there is circulation,” he explains. “They can be used to define a path or [suspended] above a conference table to define the way you intend the space to be used. Another strategy is using a wood soffit to string along a route through different spaces in order to tie it all together.”

Creative project designers are dabbling in special treatments, such as moldings, tray ceilings, and coffers. Moldings offer architectural punch, by easing the transition from the wall to the ceiling. (Another twist is tucking cove lighting behind the molding to create a gradient of ambient illumination.) Tray ceilings follow the roofline at the wall intersection and then angle from the wall to create an effect resembling an inverted tray on the ceiling.

Coffers—recessed panels or gridlike ceiling compartments—can be a rather expensive feature. However, they can add greater spatial effect and drama to a room due to the sense of greater height they lend to a ceiling, according to the Hardwood Manufacturers Association.

Another decorative trend that Dickinson has noticed is the use of “strip wood ceilings” to create undulating, arcing, and curvilinear planes utilizing the pieces of wood as facets in an undulating or rhythmically flowing shape.

	Grateful acknowledgment is made to The Hardwood Council for supplying content and images for this article. For more information about The Hardwood Council, visit: www.hardwoodcouncil.com

Dickinson has also found wood to be an effective medium for overcoming the sometimes claustrophobic effect of low ceilings. He cautions, however, that because wood ceilings are “visually very active” and usually darker than their gypsum-board equivalents, they are both “extremely wonderful and potentially tough” to execute well.

Acoustics. As ceiling surfaces significantly influence the sound performance of a space, material selection is important. As opposed to metal or plastic surfaces, wood is acoustically warm and organic—one reason acoustic instruments are customarily made from wood, according to 9Wood’s Roemen. And unlike typical acoustical ceiling tiles of cellulose and other absorptive material, wood surfaces are naturally sound reflective, with a noise-reduction coefficient (NRC) of between 0.05 to 0.15.

Wood frames and thin wood veneers are also being incorporated into hung ceiling systems. “Ceiling tiles installed in a suspended metal grid are still the most cost-effective way to create an acoustically functional and aesthetically pleasing ceiling with full accessibility,” says MMMC’s Lander, and now new products are coming on the market to introduce wood panels into this type of system. Hyer points out that removable wood tiles, which offer easy accessibility to the plenum, come in many different sizes, squares, and planks, and give “a lot of flexibility” to the designer.

It is important to be aware of how wood can be applied for different acoustical effects. According to Roemen, different levels of reflection, diffusion, and sound absorption can be achieved via the following approaches:
• Reflection – When a bright, lively sound is desired, a flat wooden surface bounces sound back into the room due to its naturally sound reflectiveness.
• Diffusion – In order to scatter reflective sound, irregular surfaces such as wood grilles or cubes, or a carved surface like wood wave tile, can be effective.
• Sound absorption – When an NRC of 0.65 to 0.90 is desired, openings in the wood ceiling (such as perforations, reveals, or grooves) enable some of the sound to pass through and get absorbed into the ceiling plenum. This approach has been used for many of the thin-veneer ceiling tiles, which use perforations and slits to help control noise.

HOW TO USE WOOD IN INTERIOR WALLS
The vertical surfaces in building interiors also present an excellent opportunity to boost building performance and kick the architectural effect up a notch. According to Tom Gray, AIA, with DRS Architects, Pittsburgh, “Special wall and ceiling treatments are critical in the overall success of an interior space, especially for commercial projects. Detailing a room with a mix of paneling, wainscoting, chair rails, crown moldings, corbels, or beams provides an opportunity to create pattern, texture, scale, and personality.”

In nonresidential buildings, says Duo Dickinson, “There is often a lower expectation of craft, and so whenever craft is present—such as expressive wainscoting or chair rails—it becomes a feature.” Wall rails and durable wainscoting offer practical benefits as well, such as protecting walls in high-traffic areas against premature wear.

Using wood on interior walls is “another creative way to add accent color to a space,” adds Hyer. “You can raise the wainscoting to 46 inches instead of 36 inches, which is the typical chair rail height, and it creates a different look and plays with the scale of a space.” Hyer says she often uses wall paneling to add visual interest to the design and help with the occupant’s perception of scale. “It’s also an easy way to add color and texture to a space, as well as address acoustic issues,” she says.

Overall, interior wood walls are commonly used in executive offices and boardrooms, as well as in healthcare settings, to help play down the institutional feel, says DRS Architects’ Lander. At the same time, McInturff points out that wood wall treatment should be used selectively, as it does cost more than drywall and other common partition types.

HOW TO DESIGN WOOD WINDOW TREATMENTS
Breaking away from the aluminum and plastic blinds that used to dominate the market, wood and faux-wood blinds and shutters are now enjoying unprecedented popularity. Judith Persit, a Palm City, Fla.-based author and expert in blinds and shutters, says wooden blinds are an important new trend in interior decorating. Duo Dickinson agrees, stating that many architects and interior designers are turning away from “the plastic and sheet-metal imitations that came to dominate the market in mid-twentieth-century America.”

Shutters  and blinds have two purposes: 1) to control lighting and solar heat gain and 2) to improve building aesthetics. As for the latter, McInturff uses such slatted surfaces to visually break up spaces, play with light, and create an evocative effect. However, Persit points out that there is a cost differential between blinds and shutters, especially with the introduction of shutter blinds, which utilize a wider slat and thus project a shutter-like appearance.

The variety of styles and fine finishes available in wood window treatments has grown dramatically, according to the Hardwood Manufacturers Association. Moreover, growing interest in wood flooring designs has encouraged greater use of wood blinds and shutters.

Wood blinds are the less expensive option, and often utilize large slats of typically southern or tropical woods to provide effective light control and visual enhancement to interior spaces. Wood shutters have improved in recent years, says Dickinson. “There are more companies making them than there have been in the last 20 years, and there seems to be a greater level of care taken in how they are produced,” he says.

HOW TO USE EXPOSED EXTERIOR WOOD
When it comes to exterior wood finishes, exposed wood cladding, trim, railing, and decks can lend great visual interest to many facilities. They can also present a serious challenge for fully maintaining material and system integrity in the face of harsh weather and climatic elements.

In fact, architect McInturff sees exterior finishes as the “weak link” when it comes to designing a truly sustainable exterior using exposed wood. First, he says, it is difficult to preserve the wood’s original color. Second, most finishes require quite a bit of maintenance, even though he acknowledges seeing progress being made on this front by finishing product manufacturers.

One of the areas of technological advance is in UV-inhibiting coatings, based upon the growing awareness that UV rays are visually and functionally damaging to exterior wood finishes. This is also in tune with green building trends, says Dickinson. “There has been an enormous push in the last decade to create effective wood finishes that will not have the potential negative impact on the environment when disposed of or when leaching into the ground,” he says.

In terms of selecting wood species to best stand up to the elements, experts recommend reclaimed and recycled old-growth products (where available), which provide a high degree of stability and a tight grain. Premium woods, such as redwood, cedar, or cypress, are common choices based on their dimensional stability and natural resistance to fungi and termites. However, Jeff Linville, director of technical services for the American Institute of Timber Construction, Englewood, Colo., points out that one thing to keep in mind when specifying naturally durable wood for decay/termite resistance is that only the heartwood of the species is resistant to attack. He advises that “it is not sufficient to specify redwood for an outdoor deck—you must also specify that it be heartwood.”

Linville, whose organization represents the glued laminated timber industry, further distinguishes between exposure to air and exposure to water. “Wood exposed to outside air but protected from precipitation does not require pressure treatment or the use of naturally durable wood. The humidity in the air is generally insufficient to raise the moisture content of the wood above the decay threshold,” he explains. He goes on to advise that wood that will be exposed to weather should be pressure-treated, unless you’re using a naturally durable species.

Linville further explains that using a simple topical treatment will not always protect exterior wood.  The method of protection must be determined early in the design process and not as an afterthought, he cautions.

DEFINING CERTIFIED WOOD
Another important consideration in today’s market is deciding whether to build with certified wood products. More and more, Building Teams say yes, and not just to get higher scores on green rating systems like LEED or Green Globes. “By demanding that the wood be certified sustainable, you pressure suppliers to reduce destructive forestry practices,” says DRS Architects’ Gray.

Fortunately, there are a number of programs utilizing third-party certification, such as the American Forest and Paper Association’s Sustainable Forestry Initiative (SFI) and the certification program of the Forest Stewardship Council (FSC). Through SFI or FSC, building professionals and end-users can be assured that their facility’s wood was harvested according to sustainable methods in forests managed by strict environmental and social standards. “The forest operation must conserve biological diversity, water resources, soil, ecosystems, and landscape to maintain the ecological function of the forest and high conservation value,” says RMJM’s Hyer.

Of course, certified wood has an important role to play when seeking many kinds of registrations and ratings. For example, says Hyer, “A building can receive a LEED credit if a minimum of 50% of wood-based materials and products comes from a certified group,” explains Hyer. But even though certified wood is becoming more and more critical to architects and builders, professionals like McInturff contend there is still a long way to go, as only 10% of the world’s forestland is certified, according to the Sustainable Forestry Initiative.

“It is important to hold manufacturers and distributors accountable to a real chain of custody,” says Gray. “Chain of custody” refers to the chronological documentation that proves where a product originated and how it reached the job site. “The more demand they see for this certification, the stronger the control over forestry practices will be,” adds Gray, who frequently specifies wood, most commonly for commercial buildings seeking LEED certification.

APPRECIATING THE BEAUTY OF WOOD
Even though there are many choices when it comes to building materials, there is still something special about wood. “Wood talks back,” says McInturff. “When you look at it, it gives something back. The color, the grain—there is something living about it. It’s a very easy way to bring warmth into a space.”

Flooring specialist Jacob Spitzer speaks for many suppliers, contractors, and other experts when he concludes, “The natural beauty and warmth of solid wood, coupled with its longevity and resilience, make it an excellent choice for a wide variety of nonresidential applications.”

About the authors
C.C. Sullivan is a communications consultant and author specializing in architecture and construction. Barbara Horwitz-Bennett is a writer and contributor to construction industry publications.

Take the AIA Exam  (one-time registration required)

This BD+C continuing education program qualifies for 1 AIA HSW learning unit.

Reed Business Information is a Registered Provider with the American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES Records for AIA members. Certificates of Completion for non-AIA members are available on request.
       This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.