A certified EnerPHit retrofit has transformed a former bungalow into a low-energy family home for Gresford Architects founder Tom Gresford. The project retains the building’s existing screed, blockwork walls and concrete lintels, while incorporating a new timber-framed extension.
Following the pandemic, Tom Gresford and his wife, Phoebe, purchased the Old Orchard site in a small hamlet in West Oxfordshire.
The property, originally constructed in the 1960s, had previously been extended and remodelled during the 1980s. Despite its age, the bungalow offered significant redevelopment potential, alongside panoramic views across the Thames Valley.
Rather than pursuing demolition and rebuild, the practice adopted a refurbishment-first strategy, using the existing structure as the foundation for the project and working in accordance with the Passivhaus retrofit standard EnerPHit.
The bungalow’s original walls, foundations and structural shell have been retained and repurposed, with much of the ground floor remaining unchanged. At first-floor level, part of the existing timber roof structure was removed to accommodate a new timber-framed extension, which runs along one side of the building’s original cruciform footprint.
New materials were used sparingly throughout the project and, where required, were selected to support its environmental objectives while responding to the character of the surrounding landscape.
The exterior is clad in western red cedar sourced from trees growing on the site, which were felled and processed at the outset of the project. Behind the cladding, the entire building has been externally insulated to deliver ultra-low U-values and enhance thermal performance, while a mechanical ventilation with heat recovery (MVHR) system has been installed.
Drawing on the area’s agricultural architecture, the roof is finished in powder-coated corrugated steel. The original ground-floor window openings were retained and fitted with new triple-glazed units, with integrated blinds incorporated into the south- and west-facing elevations.
Internally, existing stud partitions were removed to create a more open arrangement. The resulting layout is organised into a series of distinct blocks, each identified by its own colour and function, with sliding pocket doors providing flexibility between spaces.
The sole structural alteration at ground-floor level was the removal of an existing conservatory, which has been replaced with a new glazed extension opening onto a timber-framed veranda.
The new upper-floor extension is organised around a series of bedrooms and bathrooms. Introducing a playful element to the design, the stairwell and hallway are finished in a deep green colour palette, while a built-in slide is concealed behind a secret door within the wall.
In the children’s bedrooms, mezzanine levels have been incorporated, featuring openings that overlook the rooms below and internal windows that connect to the hallway.
