Swallow Street Eco Homes, Buckinghamshire

Sustainable living in Iver

Background

Our client approached us to design five Passivhaus homes on Grey Belt land in a rich and verdant landscape on the edge of Iver in Buckinghamshire.

Screened by dense vegetation, the development will provide high-quality, low-energy living in a natural setting that has been designed to enhance biodiversity and ecology while introducing greater flood resilience.

Status
On site
Approach

Construction in context - improving the green belt

Designs emerged following a deep-dive into the local architectural and historical context, with character studies identifying key takeaways from the higher-quality listed and locally listed buildings in the area.

Whilst responding to local context, we carefully designed elevations to balance heat gain and losses, daylight and aspect. We adopted best-practice glazing ratios, with 20% glazing to the front (west) and rear (east) façades and 10% glazing to side elevations.

All homes will be very highly insulated and extremely air-tight, in line with LETI best practice for detached dwellings. Initial energy modelling has demonstrated the Operational Energy Limit of <45 kWh/m2GIA/y can be met based on this approach and highly efficient MEPH services.

Our proposals limit the extent of new construction to less than half of the overall site area, giving the opportunity to improve the quality of the local Green Belt and to take advantage of the Biodiversity Opportunity Area without compromising the prevailing urban grain.

We designed building forms to be as compact as possible, with form factors in line with LETI Best Practice. All homes are dual-aspect and orientated in response to the site and local context.

Outcome

The buildings offer a contemporary interpretation of Arts & Crafts-style homes, matching the local character of tiled, pitched roofs and pale render with natural low-carbon and environmentally-certified materials proposed throughout. A chimney above each stair provides natural stack ventilation.

Facades have been composed to respond to the setting, offering generous views across the landscape. Corner glazing to the living rooms reinterpret the traditional bay window while minimising thermal bridging.

Wider windows are prioritised, with sill heights set in response to room use. Full-height glazing is avoided, with the exception of glazed doors to the garden and a narrow side panel adjacent to the main entrance door. All windows will be triple glazed with a low solar heat gain coefficient.

Initial energy modelling has indicated that by recessing windows within the depth of the external walls and limiting glazing ratios, additional external solar shading is not required for all but the south-facing windows within the 2-bed home.

All homes within these proposals are designed to achieve an equivalent of Passivhaus standards. They will all be net-zero carbon, aligned with the recently published Net Zero Building Standard based on ‘Single family homes’ and an anticipated commencement on site in 2026.

By enhancing the landscape to the rear, we achieved a demonstrable net gain in biodiversity, creating a mix of habitats that can be enjoyed by wildlife and residents alike. This offers the further benefit of screening neighbouring buildings from view within the site, while wet woodland habitats assist with the sustainable drainage and flood resilience strategy.