Mass timber's undeniable role in low-carbon construction

Mass timber's undeniable role in low-carbon construction

Friday 25 Jul 2025

A new Environmental Product Declaration (EPD) released for MASSLAM — a laminated timber product made using Tasmanian plantation hardwood by Australian Sustainable Hardwoods (ASH) with fibre from Western Junction Sawmill (WJS) — confirms its potential as a low-carbon structural alternative for multi-res and commercial construction projects.

The findings arrive at a time when the role of embodied carbon in construction is under increasing scrutiny. The Green Building Council of Australia (GBCA), in its recent report Our Homes Weigh a Tonne, found that upfront emissions are now seven times more impactful than operational emissions over a building’s lifespan.

While the report focuses primarily on Class 1a dwellings, it highlights a broader trend that applies equally — and arguably more urgently — to more intensive building typologies – Class 2 (multi-residential) and Class 5 (commercial) buildings.

Upfront emissions from materials like concrete, brick and steel are now the dominant contributors to a building’s total lifecycle carbon.

As the electricity grid becomes greener, early-stage material choices are becoming the dominant factor in determining a building’s whole-of-life carbon footprint.

MASSLAM EPD: carbon reduction backed by process, not just product

The newly released EPD for MASSLAM, independently verified under EN 15804 and ISO 14025, demonstrates a net carbon benefit of -748 kg CO₂e for every cubic metre used (A1–A3 stages, including biogenic carbon). This performance doesn’t just come from using renewable raw materials. It reflects a deliberate and integrated manufacturing approach:

Biogenic carbon (carbon stored in trees during growth) account for -1,090 kg CO₂e per cubic metre in hardwood. Sustainable forestry practices ensure more wood fibre is grown than harvested.
Vertical integration: ASH and supply partners WJS control from log to finished product. This gives complete visibility and control over sourcing, processing, energy use, and waste.
Zero timber waste: All wood fibre received is used. Offcuts and sawdust from machining are repurposed — notably, sawdust fuels thermal energy for timber drying kilns, accounting for around 80% of total on-site energy consumption. This significantly reduces reliance on fossil fuels or grid electricity.
On-site renewable power: Several NMIs (National Metering Identifiers) are in place across sites. The largest of these runs on 100% solar energy, further reducing operational emissions.

This carbon performance compares favourably to conventional structural materials such as concrete and steel, which typically incur substantial embodied emissions during production and early-stage transport.

In practical terms, this means a MASSLAM superstructure delivers a carbon benefit from day one. Traditional materials can require decades of operational savings to offset their initial impact. For projects targeting genuine decarbonisation, MASSLAM provides a substantial head start.

MASSLAM is manufactured using plantation-grown hardwood from Tasmania — fibre originally intended for pulp production but diverted to long-lived structural applications. The MASSLAM plant is capable of delivering the superstructure for the equivalent of 2,000 homes per annum using modern methods of construction (MMC).

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Source & image credit: ASH

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