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Mass timber manufactured from spruce susceptible to mould in Singapore’s hot and humid climate.
Singapore’s Nanyang Technological University (NTU) unveiled its Gaia building just over a year ago to much acclaim, positioning it as Asia’s largest mass timber structure. This S$125 million (approximately AUD $144 million) project was celebrated for its sustainable design, and was constructed with mass timber from Austrian spruce. However, the timber has encountered an issue: mould growth.
As reported by Bloomberg, the 40,000-square-metre Gaia building, which was intended to showcase the potential of mass timber construction, is now facing challenges due to its material choice. The humid climate of Singapore, where rainfall occurs on nearly half the days of the year, has exacerbated the susceptibility of its spruce mass timber to mould. Unlike more durable hardwoods, spruce is less resistant to mould and rot, especially in an environment where relative humidity hovers around 80 per cent.
Andrew Wong of the International Wood Culture Society pointed out that this issue is largely climate-driven. “We’re in the tropics, and that demands special care,” Wong told Bloomberg. The mould problem at Gaia highlights the broader challenges of using timber in diverse climates. While timber construction is lauded for its sustainability – sequestering carbon dioxide as trees grow – the reality is that different climates impose different demands on the materials used.
In Singapore, where over 20 projects have utilised mass-engineered timber in the past decade, the mould issue at Gaia is concerning. The building’s Austrian spruce was chosen for its environmental benefits, yet it has proven vulnerable in Singapore’s humid conditions. Comparatively, Singapore’s colonial-era shophouses, built with regionally native hardwoods like chengal, are naturally resistant to mould. However, the cost and availability of such hardwoods today make them a less feasible option for large-scale projects.
Despite the mould problem, NTU and the building’s architects, RSP Architects Planners & Engineers, remain optimistic about Gaia’s future. They believe that the mould is unlikely to affect the building’s structural integrity.
In response, NTU is implementing a comprehensive maintenance plan, including reapplying sealant to the timber, adjusting air-conditioning settings, and instructing staff to keep windows closed to reduce condensation. Experts recommend additional measures, such as treating surfaces with bleach and installing dehumidifiers.
