Sustainability Report

Sustainability information provided by Robert Songhurst, Associate at Hugh Broughton Architects.

• Upfront carbon: 559.2 kgCO₂e/m²
• Embodied carbon: 605.7 kgCO₂e/m²
• Whole-life carbon assessment: 3,410 kgCO₂e/m²
• To determine the embodied carbon of the project, detailed data on the volumes, areas, and lengths of all architectural, structural, and MEP components was extracted from the tender and as-built information. This data was then input into One Click LCA software, following the guidelines of the RICS Whole Life Carbon Assessment, 2nd Edition.
• While aiming for the highest accuracy, specific Environmental Product Declarations (EPDs) were not always accessible for all specified products. In these instances, generic material data was used to provide an estimate of embodied carbon and account for all materials.
• The lifecycle assessment adopts a cradle-to-grave perspective, considering the entire 50-year lifespan of the building. This encompasses environmental impacts associated with each stage of the building’s lifecycle, from the extraction of raw materials to the eventual disposal or recycling of its components.
• One of the most significant new structural elements required was the trusses supporting the new roof. Due to fire damage, the existing cast iron columns were no longer able to support the load from the roof, so the new trusses needed to span 18 metres from wall to wall. They use a core of steel plate with glulam sections bolted to either side. In this arrangement, the steel achieves the required span while the glulam resists twisting forces.
• This materially efficient arrangement significantly reduces the quantity of steel required compared with a wholly steel-framed design. The remainder of the roof above is traditionally framed in timber, both appropriate to the building’s heritage and providing a significant store of sequestered carbon.
• Both materials and labour were sourced locally where available. The new concealed steel frame supporting the clocktower, for example, was fabricated by SKJ, based in the dockyard barely 400 metres from Dockyard Church. This approach was primarily chosen to maximise the project’s local socio-economic impact, with reduced transport-related carbon emissions being a welcome additional benefit.

• A TM52 overheating assessment was conducted at the design stage to assess the development’s resilience to rising temperatures. All spaces are compliant with TM52 criteria using a natural ventilation strategy. This passive ventilation strategy minimises operational energy consumption and therefore operational carbon emissions.
• Metered energy consumption has subsequently been compared with the estimates produced during design. Observed gas consumption for space heating is substantially lower than predicted, which Hugh Broughton Architects attributes largely to conservative assumptions for fabric performance and other factors used in the original MEP modelling. Electrical consumption is slightly higher than estimated, likely due to cafe food preparation and internal lighting use exceeding the quantities originally anticipated.
• Gas consumption: predicted 188 kWh/m²; observed 115 kWh/m²
• Electricity consumption: predicted 41 kWh/m²; observed 47 kWh/m²
• The observed values are comparable to, and in some cases slightly below, median energy use intensities for buildings with similar uses in England and Wales, based on the UK Government’s 2025 Non-domestic National Energy Efficiency Data Framework.
• Hugh Broughton Architects considers this measured performance particularly encouraging for an adapted early 19th-century church.

• All decisions made throughout the project — from the building’s new use to the selection of materials and techniques for its restoration — aimed to ensure the ongoing viability of Dockyard Church for future generations.
• A programme of detailed structural investigations and repairs, together with the specification of hard-wearing and readily maintainable finishes, will allow the building to operate for another 50 years before major renovations are needed.
• The design sought to retain all salvageable existing fabric, including the reuse of masonry materials that had become unstable and were therefore carefully dismantled, labelled, and returned to their original locations. Existing structural elements were evaluated, repaired, and reused, including the vaulted brick foundations, cast iron columns, and mass masonry walls.