Sustainability Report

An exemplar of sustainable development and low-impact design by Thomas McBrien

Embodied carbon

Low Carbon

Carbon Emissions

-35

kg CO₂-eq./m²

The embodied carbon of the new extension is calculated at 166 kg CO₂e/m². However, when carbon sequestration is factored in, specifically the project’s 41.208 cubic metres of glulam timber, which absorbs and stores carbon throughout its lifecycle, the embodied carbon value is reduced to -35 kg CO₂e/m².

Operational Emissions / Energy

Low Carbon

Since the building’s energy and gas systems are centralised, the new extension cannot be isolated. Therefore, operational carbon calculations include the total GIA of 1,725 square metres, which encompasses the existing two floors (1,230 square metres) and the newly constructed timber roof extension (495 square metres).

Timber roof extension

The timber roof extension was completed in late November 2023 and occupied from 1 December 2023. Energy data (meter readings) for the entire building was collected over a two-year period: 12 months pre-completion (1 December 2022 – 30 November 2023) and 12 months post-completion (1 December 2023 – 30 November 2024).

Pre-completion and occupation (1 December 2022 – 30 November 2023)

Electricity: 53,045 kWh/yr
Gas: 107,850 kWh/yr
Total: 160,895 kWh/yr
GIA of existing two-storey building: 1,230 square metres
Energy use per square metre (pre): 130.81 kWh/m²/yr

Post-completion and occupation (1 December 2023 – 30 November 2024)

Electricity: 56,865 kWh/yr
Gas: 111,950 kWh/yr
Total: 168,815 kWh/yr (representing a 4.9 percent energy usage increase from the previous year)
GIA of existing two-storey building including timber roof extension: 1,725 square metres (the new extension represents a 40 percent increase in GIA of the existing building)
Energy use per square metre (post): 97.86 kWh/m²/yr

The 97.86 kWh/m²/yr represents a significant improvement, with a 25 percent decrease in energy use per square metre. This is especially notable considering the 40 percent increase in floor area. This reduction in energy use per square metre demonstrates improved sustainability, efficiency, and cost-effectiveness, all achieved through thoughtful design and optimised building performance.