a b e au t i f u l , va lu e - a d d e d a p p l i c at i o no f b r i t i s h c o lu m b i a h e m l o c k

WHISTLER PUBLIC LIBRARY

Whistler Public Library

architecture the resort municipalit y of whistler is nestled in theCoast Mountains of British Columbia, about 75 mi (125 km) north of Vancouver. The new building, completed in 2008, provides state-of-the-art facilities and a new civic presence for Whistler’s only public library. Designed within the framework of Whistler’s comprehensive sustainability plan (www.whistler2020.ca), the form of the building responds to solar orientation and the conditions of its site, mediating between the urban edge of Whistler’s Village Stroll and the dramatic natural setting of the adjacent park and the mountains beyond. In so doing, it provides a new interpretation of the municipality’s design guidelines, and a new and more honest expression of what it means to build in a mountain environment.

On its sloping site, the L-shaped library sits atop an underground parking garage, bringing the main entrance level with the adjacent street. To improve site utilization, and eliminate removal costs, it was decided to design the building to retain snow on its roof. This strategy had implications for the structural design of the roof, but also supported the architect's desire for a shallow shed roof in response to site conditions. Low at the south side, facing the street, with overhangs to prevent solar heat gain in summer, the roof rises to the

north, bringing in the even light that is conducive to a good reading environment and opening the building up to panoramic views of the park and mountains. In addition to large areas of glass, the building exterior is clad in stone, western red cedar siding and composite panels.

The population of Whistler is divided into three groups of residents: permanent, week-enders, and seasonal workers. For permanent residents, the library is an affirmation of the community's cultural life and provides an enriching environment for research and reflection. Week-enders are offered a respite from the bustle of the commercial centre, while seasonal workers find a ‘community living room’ that is a warm and welcoming meeting place beyond the confines of their often cramped living quarters. A stone fireplace built into the north wall and reclaimed Douglas-fir millwork enhance the warm feeling of the interior.

“The response from the community has been extremely positive; all the things we strived for are what people are reacting to—the space, the light, the fact that it is authentic in its expression.” darryl condon, principal - hughes condon marler : architec ts

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Main Entry Entry Vestibule Circulation Desk Patron Service Book Drop Workroom Head Librarian Office Copy/Storage Storage Office Staff Room

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Child Program Room Children's Area Group Study Quiet Carrels Outdoor Reading Terrace Reading Room Fireplace Teen Area Computer Lab Multipurpose Room Arcade

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facts

• The 14,500-ft C (1,350-mC) building—Whistler’s only public library—reinterprets the municipality’s design guidelines in a contemporary architectural expression

• The shallow shed roof is designed to retain snow and to supportsignificant loads—a 50-lb/ft C (245-kg /mC) green roof and 165-lb/ ftC (815-kg/mC) snow load

• The building features an innovative, solid wood roof system comprisingprefabricated panels made of solid hemlock members free spanning distances up to 45 ft (13.5 m)

structure to date, whistler’s design guidelines have mostly resulted in very simple structural solutions in which oversized post and beam construction and unsophisticated bolted connections predominate. The effect is generally rustic and traditional rather than elegant and contemporary, and few buildings communicate the way in which the very substantial snow loads and other forces are resolved. From the outset, the desire was to create a building that was unmistakably contemporary, with a clear and honest expression of structure.

The form and layout of the building began to inform what the structure would have to be. With meeting rooms and other ancillary spaces arranged along the south and east sides of the building, facing the street, the reading room and study area became a single, column-free space on the other side, facing the park. This created the need for a shallow-pitched shed roof configuration with clear spans up to 45 ft (13.5 m), and with 10-ft (3-m) overhangs to provide covered walkways and entrances on the street side.

The prefabricated, solid hemlock panel system used for the roof meets these various criteria within a structural depth of only 16 in (400 mm). The 4-ft (1,200-mm) wide panels were laid with a

12 in (300 mm) gap between them that creates a cavity in which to run sprinkler lines and other services. The gap also provided the opportunity to conceal the additional steel members that are necessary for certain non-standard roof conditions—such as where the eaves are turned up above the entrances to ensure snow does not slide from the roof and inadvertently fall on people entering or leaving the building.

Support conditions for the panels vary: concrete walls at the low end of the roof, steel I-sections at the internal valleys and glulam beams in feature areas. At the high end of the roof, above the window wall that faces the park, hollow steel sections are used between the glulam columns to minimize the structural depth and any obstruction of the mountain views.

At the entrance, the roof overhang rests on a V-support; the angled heavy timbers follow the lines of force and are joined by discreet hidden connections. Elsewhere roof projections are supported on paired, angled struts that pick up the rhythm of the arcades along the Village Stroll.

facts

• Hemlock is an abundant but under-valued and under-utilized speciesthat is readily accessible throughout British Columbia’s coastal forests. Local sourcing and fabrication make hemlock an environmentally responsible choice for this project

• The roof panel system represents a precedent-setting value-addedapplication of hemlock that clearly demonstrates its commercial viability

• Whistler’s municipal council mandated that the building shouldachieve a Leadership in Energy and Environmental Design (leed®)Silver rating. If all credits claimed on the application are accepted, it will achieve leed Gold

wood andsustainability

in reco gnition of the imp ortance of the outdoorenvironment for cultural life in Whistler, a strong emphasis was placed on innovative sustainable building strategies in which the use of wood played a dominant role. During the schematic design phase, the project team was approached by the British Columbia Coast Forest Products Association seeking to showcase the use of sus tainably harvested hemlock in the project.

Hemlock is a readily available species that is currently under- utilized in wood construction. Widely dispersed in coastal forests, second growth hemlock in particular can be a highly sustainable product, although it may be necessary for designers to take into account some dimensional variability.

The design team developed a panel system of staggered and lag-screw laminated members (4 * 12 in, 100 * 300 mm) that were fabricated into 4-ft-wide panels and cut to length as required. In between the panels a 12 in (300 mm) space was left to run services such as sprinklers and lighting conduit, leaving the wood soffit clean and uncluttered.

While at first glance a solid wood ceiling might not appear to be an optimal use of material, a broader comparison with more conven-

tional alternatives, such as glulam and purlin construction, identified several other advantages from the point of view of sustainability. As a low-tech, locally sourced material, locally fabricated into panels, solid hemlock had lower embodied energy than the alternatives. And, by minimizing the depth of the roof structure, the overall volume of the building was reduced, which in turn reduced envelope area and life-cycle energy consumption.

Architecturally, the panels also provide an elegant yet robust ceiling expression that reduces acoustic reverberation and reinforces the sense of connection between interior and exterior by continuing beyond the glazing line to form overhangs and soffits.

“Build a quality facility that inspires a community and they will come: usage is up 300% over the old facility and library staff cannot keep up with the demand for programs and services. It’s like a fitness centre for the mind where the admission is free.” martin pardoe, manager of resort open space pl anning

– resort municipalit y of whistler

solid hemlock roof panel system

The innovative, solid wood system that was ultimately chosen for the library roof was carried through schematic design alongside more familiar solutions such as a conventional glulam, purlin and deck system. With the L-shaped plan determined, the issue became one of how to clear span distances up to 45 ft (13.5 m) with the available hemlock material, which was in lengths of 20, 24 and 26 ft (6.0, 7.2 and 7.8 m).

Adjacent timbers were offset horizontally to increase the spanning capabilities, and were securely fastened together to ensure effective load transfer between laminations. Alternate laminations were offset 3 in (75 mm) vertically, creating corrugations that increase the effective depth of the panel and enhance its spanning capabilities under the 50 lb/ ft C (245 kg/mC)loads of the green roof and 165 lb/ ft C (815 kg /m C) live snow loads. The verticaloffset also created a consistent top and bottom datum for the panels making detailing at the bearing points more straightforward.

For the longest spans, a steel kingpost and cable system was devised to increase the effective depth of the panels, and was installed once the panels were in place (see details). The simplicity of the kingpost and cable design also provided the contractor with the flexibility to install these components either in the shop or on-site. In the end, site installation was chosen as it offered easier handling of the panels and greater erection tolerances.

The panels were modelled in 3d software and then prefabricated in StructureCraft's shop in Delta, British Columbia in an effort to reduce the construction time. The initial panel design also determined that the layers of sheathing plywood could bridge a 12-in (300-mm) wide space unsupported, thus reducing the overall amount of material required for the roof and creating the service void referred to above.

north elevation

west elevation

4-19Ø STEEL PINS PER TYP.DETAIL A/S3.4 SET IN 22 WIDEx40 DP. VERTICALLY SLOTTEDHOLES IN KNIFE PLATE

HORIZ. LEG OF ANGLEFASTENED TO GLULAMBEAM WITH 2-19 x19Ø LG.GALV. LAG SCREWS

BEARING PLATE25mm H.D. GALV.

SEE PLANGLULAM BEAM

6mm THK. H.D. GALV.KNIFE PLATE

2-19Ø STEEL PINS PER TYP.DETAIL A/S3.4 SET IN 22 W x40 DP. VERTICALLY SLOTTEDHOLES IN KNIFE PLATE

L203x152x11 H.D. GALV.C/W 2-19Øx200 LG.GALV. LAG SCREWSCONNECTION TO SOLIDWOOD ROOF PANELS

BEVEL CUT T/O GLULAM BEAMTO ALLOW FOR ROOF SLOPE

6mm H.D. GALV. KNIFE PLATE

DOUBLE GLULAMCOLUMNS SEE PLAN

SOLID WOODROOF SEE PLAN

SOLID WOOD PANELS

GLULAM BEAMSAND COLUMNS

KINGPOSTS & CABLES

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“Hemlock is readily accessible throughout the coastal forests of British Columbia, but its potential has been largely overlooked. This roof system shows that hemlock can be a value-added product, as well as an inherently sustainable one.”

duane palibroda , senior associate engineer – fast + epp struc tur al engineers

project credits

clientResort Municipality of Whistler

architectHughes Condon Marler: Architects

structural engineerFast + Epp Structural Engineers

mechanical engineerStantec

electrical engineerAcumen Engineering

landscape architectPhillips Farevaag Smallenberg

general contractorWhistler Construction Company Inc.

building code consultantLMDG Building Code Consultants Ltd.

building envelope consultantRDH Group

cost consultantBTY Group

roof panel fabricatorStructureCraft Builders Inc.

photographersKK Law, Nic Lehoux, Martin Tessler

for technic al inquiries www.wood-works.ca1-877-929-9663

CanadianWoodCouncil

Conseilcanadiendu bois

Consider the environment — use paper from responsibly managed forests. Published October 2010