At 52 metres tall and 14,965 m2 of office NLA spread across 10 floors, 25 King Street is Australia’s largest commercial office building constructed with Cross Laminated Timber (CLT) and glue laminated timber (Glulam).
As part of the $2.9 billion renewal of the Brisbane Showgrounds in Bowen Hills QLD, the project sits within one of Australia’s biggest urban renewal initiatives.
Now home to its engineering team Aurecon, it holds many sustainability ratings including a 6 star Green Star Design and As-Built rating, NABERS 6 star office energy, 4.5 star water and 3.5 waste ratings and Carbon Neutral certification for base building and a Platinum WELL Shell and Core rating.
The project team wanted a building that would visibly express sustainability and engineering. Since concept stage, upfront carbon emissions and decision to build with timber was established.
25 King Street reduced upfront carbon within Modules A1 –A3 by 38.7% when compared to a reference building.
The key upfront carbon reduction design initiatives at 25 King Street included:
- Engineered timber was used in lieu of carbon intensive concrete and steel for structural columns and beams
- Minimalist internal finishes with CLT cladding and flooring with no suspended ceilings systems throughout
- 40% reduction in overall Portland Cement use
A Life Cycle Inventory was established from the building cost plan, preliminary bill of quantities and site construction bill of materials, as well as drawings, specifications, environmental product declarations and the like, using the GaBi Professional + Extension Database. The scope for upfront carbon was Modules A1 to A3.
The Reference Project comprised of a standard concrete/steel construction, while the Proposed Project was of a Cross Laminated Timber (CLT) and Glulam structure. The structural design of the two cases is consistent, using a post and beam construction, however the physical quantities of structural materials (concrete and steel compared with CLT and Glulam) vary between the Reference Project and the Design Case. These quantities of structural materials have been determined for both the Reference and Design Cases by engineering and cost planning experts and the bill of quantities. Where data was unavailable, the study uses estimated inputs based on similar projects.
The focus on sustainability within design attracts more and higher quality tenants and lower vacancy risk. 25 King Street offers high-end office space with strong lease covenants. Its tenants, as reported by IIG, have been attracted by 25 King’s amenity, innovation and overall quality, including the extensive use of engineered timber to drive environmental performance.