25 King: Brisbane's Timber Office Building

25 King, developed by Bates Smart, is a groundbreaking project located in Brisbane, Australia, exemplifying innovation in timber construction. This 10-level office building spans 14,965 sqm NLA and was completed in 2018 on the historic RNA Showgrounds. The design philosophy behind 25 King emphasizes sustainability and the honest expression of materials, distinguishing it from conventional office developments. Its architectural concept is not just a mere boutique experiment but presents a commercially viable alternative to traditional steel and concrete construction in mid-scale office environments.

The architectural marvel of 25 King features an extruded glazed rectilinear form that articulates its floorplate effectively. Its all-timber side core on the northern side allows for a spacious, unencumbered floorplate, fostering maximum workplace flexibility. The innovative 'L' shaped solar shades on the west façade are designed to mitigate solar heat gain, a critical aspect considering Brisbane's harsh climatic conditions. Additionally, the glazed 'verandah' volume enhances the primary street frontage, offering a beautifully shaded pedestrian experience with a blend of indoor and outdoor retail spaces.

In terms of structural integrity, the basement and ground floors of 25 King utilize concrete construction due to moisture concerns and the risk of white ants. However, the upper levels showcase a fully timber-based column and beam structure, marking it as Brisbane's first timber commercial building. The project ingeniously resolves various structural challenges while optimizing for economic transport and handling on-site. The 6x8 metre grid used in the design allows for reduced dimensions of columns and beams, contributing to a slender aesthetic that resembles fine joinery, further enhanced by the use of glulam timber for the columns and beams and cross-laminated timber (CLT) for the floor planks and core walls.

To enhance the functionality of the workspace within 25 King, services are strategically left exposed beneath the timber structure, with critical utilities organized in specially designed zones that feature shorter spans and reduced structural depths near the core and façade. This design choice not only maximizes floorplate flexibility but also contributes to a visually appealing interior space. The warm aesthetics of timber, emanating from the columns, beams, and floor soffit, help create a serene environment that connects employees with nature, ultimately promoting a healthier and more enjoyable workplace.

25 King stands as a global benchmark in timber architecture, showcasing a unique blend of structural, construction, and sustainable efficiencies. It holds the distinction of being the tallest timber commercial building with the most extensive floorplate in the world. This project demonstrates the feasibility of timber construction as a competitive option against traditional materials like steel and concrete, paving the way for future developments in sustainable architecture.

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