Exemplar Sustainable Building Awards: Small project finalist: Long Four Acres
Small project finalist in the 2025 Exemplar Sustainable Buildings Awards. Long Four Acres is a two storey detached self-build in South Norfolk that has been modelled in PHPP and designed, but not certified, to the Passivhaus Plus standard. While airtightness of 0.8 ach @ 50 Pa was just shy of Passivhaus criteria (0.6 ach @ 50 Pa) the building performance in practice aligns closely with PHPP Passivhaus Plus expectations.
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The house was built on a plot that was one of 15 with outline planning approval for an energy-efficient selfbuild. The builds were required to comply with a plot passport and a design code; that constrained height, footprint and proximity to boundaries, as well as materials choice. Seeking efficiency led to a simple form, which, combined with the need for a swift build, led to the choice of a mono-pitched roof timber frame design.
The clients' aspiration was to use natural materials wherever possible. The house is built with timber frame and filled with cellulose insulation. Embodied carbon calculations have not been undertaken for this project but are estimated to be less than 500 kgCO2e/m2. The off-site timber frame approach lent itself to low carbon construction at pace and most elements of the build were found to be straightforward. The project's renewables requirements contribute to the home's exceptionally low running costs. Judges were impressed by the simplicity and potential replicability.
Key StatsCertiication: Targeted Passivhaus Plus Date occupied: 2020 Treated Floor Area (TFA): 190 m² Construction cost: £2,374/m2 Annual running costs:
Heat source: ASHP Overall energy demand: 25.1 kWh/m2/a (EUI) Embodied carbon: Estimate < 500 kgCO2e/m2 Construction: Timber frame with cellulose insulation |
Key TeamClient: Martin Ingham Architect: Parsons Whittley/ VOID Architecture Contractor: MBC Timber Frame & clients Passivhaus consultants: Martin Ingham M&E Design: Alan Clarke Timber frame: MBC Timber Frame MVHR supplier: 21 Degrees Certifier: WARM |
Join us on the 24th June at the Awards Ceremony to vote for your winners!
Further information
Exemplar Sustainable Building Awards Phase 1 submission: Long Four Acres
VOID Architecture: Long Four Acres
2025 Exemplar Sustainable Building Awards
14th May 2025
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