Wood ceilings combine beauty with performance

by sadia_badhon | February 26, 2020 10:20 am

by Sean D. Browne

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Wood ceilings can not only provide inviting, eye-catching aesthetics, but also effective acoustical control, making them a versatile and functional design element. To obtain the acoustic benefits, the panels must be perforated and backed with a sound-absorbing material.

Designed to impart warmth to a space, wood ceilings continue to grow in popularity. One reason for that is they offer shorter lead times and lower costs than custom millwork. Another is their ability to create a rich, natural, custom look using only standard panels. Third, today’s wood ceiling systems are offered in a wider variety of sizes, shapes, and forms than ever before.

By combining beauty with performance, wood ceilings are especially well-suited for use in applications ranging from retail, healthcare, hospitality, office environments, and higher education to lobbies, entryways, and conference rooms. Long popular in European commercial design, this traditional material can impart a visual impact that makes it a focal point in signature spaces.

Wood is also gaining increased usage in ‘free-floating’ acoustical clouds and canopies, especially in exposed structure applications. In both cases, the cloud or canopy must be perforated and/or backed to obtain acoustical benefits.

Variety of choices

Wood ceilings are made with either real wood veneers or solid wood. Due to all the variations in color, grain, and texture, there are scores of finishes to choose from. In the case of veneers, white oak, light cherry, and dark cherry are the most popular. Custom veneers are also available. The most common solid wood is poplar.

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When it comes to sizes, shapes, and forms, the myriad of choices include the following.

Tegular

These are square or rectangular panels in which the face of the panel is lower than the face of the grid. Panel sizes usually range from 610 x 610 mm (24 x 24 in.) to 1219 x 2434 mm (48 x 96 in.). Tegular wood panels are also offered in triangles, trapezoids, and parallelograms as part of a new ceiling system that gives architects the ability to mix and match different panel shapes, sizes, colors, and textures.

Linear

This is offered in either planks, panels, or channeled in veneered wood or solid wood. Plank widths are much narrower than panel widths.

Concealed 

The suspension system is completely hidden for a monolithic visual. Panels are installed on suspension system with hooks.

Grille

This type is growing increasingly popular as design trends embrace the linear look. It provides wide choice of slat widths, heights, spacing, and number of slats per panel.

Case study

Baptist Health South Florida wanted the design of its new Miami Cancer Institute in Miami, Florida, to reflect the warm Mediterranean style of the other healthcare facilities it operates.

“The client wanted to create a friendly, hospitality-type feel such as you would find in a fine spa or hotel,” said Barbara Kubasti, principal at ZGF Architects.

Inspired by the connections to nature found in the surrounding landscape, the design team selected natural materials for the interior of the center, creating a comforting environment for patients and families.

Reinforcing the connection to nature, the lobbies and corridors feature wood linear veneered ceiling panels in a cherry finish. Each of the custom panels comprise three different widths of wood planks with a narrow reveal between each one, creating a linear visual aligning directionally with the corridors.

“We wanted the warm feel of wood and because the wood ceilings are linear in fashion, they accommodate the continuance of the long corridors that form the circulation spine of the building,” explains Kubasti. “The panels are backed with a factory-attached acoustical fleece to help control noise in the areas where they are installed.”

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The eye-catching wood linear veneered ceiling panels provide patients and families with a quieting connection to nature that helps in the healing process, while also serving as a wayfinding tool which helps with navigation around the building.

Acoustic performance

In the past, specifiers often had to make a trade-off between sight and sound, between aesthetics and acoustics, when it came to wood ceilings. Today, that is no longer the case as there is a broad range of options affecting acoustical performance.

To obtain the acoustic benefits of a wood ceiling, the panel must be backed with a material to absorb sound. Perforations in the panel increase the absorption of sound striking the surface.

The number, size, and shape of the perforations and the percent of open area all affect the acoustical absorption of the ceiling panel. Perforations vary in size and pattern depending on aesthetic appeal. For years, only limited perforation choices were available. Now, perforations are offered in a myriad of shapes including custom ones. Circles and ovals are the most popular.

Today, it is also possible to have microperforated panels in which the perforation openings are so small, they are virtually invisible. The result is the look of solid wood but with the ability to absorb most of the sound striking it.

The perforation pattern also affects the acoustical absorption of the ceiling and can impart a compelling visual effect. The most common standard patterns include horizontal and vertical rows, slots, and diagonals. Custom patterns are available as well.

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Backloading the panel

The sound-absorbent material behind the perforations is usually in the form of a black acoustical fleece, encapsulated fiberglass, or a mineral fiber infill panel. The thickness and density of the material will affect its acoustical properties. In typical applications, the absorbent material is placed on top of the wood panel with an air gap between it and the deck above.

Today, it is possible to obtain the acoustic benefits of both sound absorption and sound blocking in a wood ceiling at the same time. To do so, it is recommended to back the perforated wood panel with a mineral fiber infill panel that has a noise reduction coefficient (NRC) of 0.60 or higher and a ceiling attenuation class (CAC) of 35 or higher in the same panel.

The NRC rating indicates the sound absorbing performance of a material. A ceiling panel with an NRC of 0.60 means it will absorb 60 percent of the sound striking it. The higher the NRC, the more the material prevents noise from bouncing around the room, reduces noise levels and reverberation time, and enhances speech intelligibility.

The CAC measures how well a material blocks sound from traveling from one space to another. The higher the CAC, the more the material reduces noise from adjacent spaces, ensures speech privacy, and provides quiet for concentration and focus. Panels with a CAC of 35 or greater represent high performance and are well-suited for spaces where speech privacy is a key consideration.

Case study

The administration building at Lyric Opera of Kansas City, Missouri, houses the regional opera company’s offices. When designing the space, architect Richard Hu of HJM Architects wanted to include a material that would add warmth to the building’s two-story lobby and open reception area on the second floor.

“The building has a very industrial aesthetic,” explained Hu. “Everything is exposed. We needed a warm material to offset all those cold, hard surfaces.”

The design team also needed to control acoustics. “The lobby is all concrete and glass, so it can get pretty noisy,” said Hu.

To accomplish both goals, the design team selected acoustical clouds comprised of concealed wood ceiling panels. Five acoustical clouds consisting of dark cherry wood veneer ceiling panels were suspended in a sloped, ribbon-like pattern above the space. Each cloud consists of a single row of standard panels with coordinated trim and a narrow reveal between each one.

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In addition to adding warmth, the wood veneer panels also improved acoustics in the lobby and reception area. The panels are perforated in an oval, straight-slotted pattern and backed with a fiberglass infill for acoustical control.

The design team was pleased with the result, noting the ceiling design complemented other linear elements in the building.

“We were trying to do something dynamic that drove people directionally to the upper lobby,” says Hu. “The ceiling design not only provides subtle wayfinding, but also a nice, rich look—almost like a tapestry.”

Accessibility

As building services equipment overhead becomes increasingly complex, ease of access to the plenum becomes more of a priority. Routine cleaning and servicing of ductwork, air diffusers, plumbing, fire protection, and the like require easy accessibility. The installation, maintenance, and updating of today’s generation of cable and lighting technology and wireless access points adds even more demand for access.

To achieve an accessible wood ceiling, tegular assemblies with ‘hook-on’ installation are the easiest to install and provide full downward accessibility for safe, efficient removal of panels. More complex wood ceilings, including custom flat, curved, and radial, can also be designed for access.

Case study

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Owners of the Gulf Canada Square Food Court in Calgary, Alberta, decided it was time for an update and commissioned Stantec to refresh the space with a design that would work with the existing seating configuration.

To attain that goal, the existing drywall ceiling had to be replaced with a more dynamic one.

“We needed to find a solution that would be visually exciting and be easily removed to service the equipment in the plenum,” said Craig Ainsworth, lead architect.

The solution was a custom wood access ceiling system that radiates out in a sunburst design.

“The space lent itself to an oval shape so we just played off that shape and the placement of the existing structural columns to develop this large wood ceiling with lines radiating out from the center,” said Ainsworth.

The 316-m² (3400-sf) ceiling consists of 234 wood panels in a dark cherry finish that gradually get smaller as they approach the center. With a consistent reveal between each of the panels, the design team was also able to take advantage of the acoustical properties of the new ceiling.

“Since sound could penetrate up into the plenum, we were able to take advantage of the acoustic treatment on the back of the panels,” Ainsworth explains.

The panels are suspended from a grid system that was painted black to obscure the equipment in the plenum.

“Everything behind the ceiling disappears so the wood panels become the dominant plane of the ceiling,” said Ainsworth.

Installation and humidity

The most important part of a wood ceiling installation is making sure the panels are acclimated to the space. All wood panels are hygroscopic, meaning they respond to changes in humidity levels. Consequently, the HVAC system must be in place and in operation before installation.  For best results, it is important to follow the manufacturer’s recommended guidelines for temperature and humidity levels. The temperature range with normal HVAC in operation is usually 10 to 30 C (50 to 86 F) with a relative humidity of 25 to 55 percent. The wood panels should also be stored in the conditioned space at least 72 hours before installation.

Wood ceiling panels are heavier than traditional acoustical ceiling tiles. As a result, they need to be installed in a heavy duty suspension system instead of a standard system. When creating a reflective ceiling plan, it is important to try to limit cut panels as the exposed edges have to be stained to match the panel.

In the past, installing light fixtures in wood ceiling systems was a challenge, especially in terms of integration. Today, as a result of ceiling manufacturers partnering with lighting manufacturers, pre-engineered lighting integration options are now offered. Specially designed low-profile, light-emitting diode (LED) linear luminaires are available that are the exact length of a ceiling manufacturer’s panels, resulting in a flush, sleek visual. The fixtures are attached to the suspension system using a special connection clip, eliminating the need to independently suspend them from the deck.

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Seismic performance

The seismic performance of wood ceilings is primarily determined by the installation of the suspension system. The purpose of installation requirements for suspended wood ceilings where seismic performance is a factor is to provide a system strong enough to resist lateral forces imposed upon it without failing and to prevent border panels from falling from the ceiling plane.

Any panel weighing 1 kg (2.5 lb) per square foot or more (which is most wood) must also be installed per the additional installation requirements of Seismic Design Category D, E, and F.  Some jurisdictions, including the California Building Code (CBC), require wood or other hard or heavy panels to be positively attached to the suspension system.

Sustainable spaces

Environmentally, many of today’s wood ceilings are certified as products representing responsible production and consumption practices from the forest to the consumer. The major environmental certifications for wood ceilings are as follows.

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Forest Stewardship Council

Forest Stewardship Council (FSC) certifies that wood products come from responsibly managed forests through a verified chain of custody.

Rainforest Alliance

Rainforest Alliance certifies wood products are sourced from forests managed to protect endangered species, areas with high conservation value, workers, and communities.

US Department of Agriculture BioPreferred

This certifies bio-based products from plants and other renewable sources.

Additionally, environmental product declarations (EPDs) are standardized, internationally recognized, independently verified, comprehensive descriptions of a product’s full environmental impact. Natural substrate and veneer materials can also make significant contributions to Leadership in Energy and Environmental Design (LEED) credits.

Assistance available

The increasing popularity of wood ceiling systems for sound control has resulted in the need for much more collaboration between specifier and ceiling manufacturer, especially in the case of custom installations. To meet this need, a number of ceiling manufacturers now offer a consultative design service that provides project management for the ceiling system, from concept to completion. It consists of specialists with expertise in both architecture and engineering whose sole mission is to partner with architects and designers in the implementation of signature ceilings.

Warm acoustical element

Wood is often one of the most elegant and warm architectural element in a space. As a result, its use in acoustical ceilings is perceived as upscale and stylish, even when used with a standard suspension system and ordinary light fixtures. Since ceilings can also reduce noise levels and help create a calmer interior environment makes the specification of wood ceilings a viable choice, whether it is a new construction project or the renovation of an aging space.

[9]Sean D. Browne is senior principal scientist for Armstrong Ceiling & Wall Solutions in Lancaster, Pennsylvania, where he leads the Armstrong acoustics program. A member of the Acoustical Society of America (ASA) and ASTM International, Browne has engineering degrees from Florida State University and the University of Miami, and has been published in the journals of the International Symposium on Room Acoustics (ISRA) and Acoustical Society of America (ASA). He can be reached at sdbrowne@armstrongceilings.com[10].

Source URL: https://www.constructionspecifier.com/wood-ceilings-combine-beauty-with-performance/

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