Grangewood, Bledlow Ridge

The Green Belt argument was based upon openness, massing and visible geometry, rather than floor area alone. The planning analysis demonstrated that the principal existing house measured approximately 1,379 m³. The closely related habitable annex added approximately 318 m³, bringing the existing residential built volume to approximately 1,696.62 m³. The proposed replacement measured approximately 1,760 m³. The resulting increase was therefore only around 3–4%. At the same time, the new house consolidated accommodation previously spread between different buildings, generally reduced the ridge profile, removed ancillary structures, reduced the overall width of built development facing the valley, and used substantially more of its internal volume as useful accommodation. The planning statement expressly identified the additional internal floor space as the result of intelligent spatial configuration rather than a comparable increase in visible built form. Buckinghamshire Council ultimately accepted the principle of this approach. The officer report concluded that the replacement dwelling would not result in a loss of openness in the Green Belt. Full planning permission was granted under 21/07874/FUL on 29 December 2021 for demolition of the existing dwelling and ancillary accommodation and construction of the new five-bedroom house, together with parking, landscaping, pergola and swimming pool. This was achieved despite the considerably more restrictive position communicated by the Local Planning Authority during the earlier pre-application process.

Numerical compliance alone would not have been sufficient. Grangewood occupies a prominent position within the Chilterns landscape and can be seen from longer views across the valley. The pre-application response therefore identified massing, ridge height, landscape integration and long-distance visibility as important considerations. The new architecture was developed around two principal gabled forms connected by a more restrained central element. The replacement also reduced the approximate width of built structure presented towards the valley from 35 metres to 20 metres, while much of the proposed ridge remained lower than the existing building. Removing disparate existing buildings and consolidating the architecture consequently allowed a much larger house internally while creating a calmer composition externally.

The basement was not simply an additional floor. It was an important part of the planning strategy. By moving substantial ancillary accommodation below ground, functions which would ordinarily generate visible development could be accommodated without materially affecting the landscape. The basement incorporated significant parking provision, cycle storage and related accommodation. The planning statement confirmed capacity for more than four vehicles together with electric vehicle infrastructure and cycle parking below ground. This substantially reduced the need for detached garages, visible parked vehicles and additional above-ground development. It also allowed the main house to concentrate its most valuable above-ground volume on primary living and bedroom accommodation.

The planning process continued after the principal consent. As the design moved into technical development, changes to the approved plans and parking/manoeuvring arrangements were coordinated through a formal variation application. Application 22/06016/VCDN was approved on 7 June 2022. The variation allowed the emerging detailed design to be reconciled with the planning permission while retaining the fundamental Green Belt strategy secured through the original consent.

The principal permission contained a series of controls relating to arboriculture, ecology, external lighting, landscape design, biodiversity, parking, water efficiency and future development rights. Cohanim coordinated these secondary approvals alongside the technical development of the house. The submitted Arboricultural Method Statement and Tree Protection Plan were accepted under Condition 6. The ecological lighting strategy was also approved under Condition 7, using external low-glare dimmable lighting designed in accordance with Bat Conservation Trust guidance. Landscape design became an important part of the planning compliance process. Condition 10 required a coordinated landscape scheme demonstrating future tree canopy cover of at least 25%, biodiversity enhancement, tree retention and replacement, and details of proposed planting. The first condition-discharge submission was not accepted because the Council required clearer evidence of biodiversity gain and additional planting. The landscape design was therefore developed further rather than treated as a peripheral planning requirement. The revised proposals incorporated retained woodland together with substantial new planting, wildflower areas, bird boxes, saplings and a new fruit orchard. This allowed the wider landscape strategy to reinforce the architectural objective of reducing the perceived impact of the replacement dwelling within its rural setting.

The scale of the basement and replacement dwelling required careful coordination of drainage and ground conditions. Although the property itself is in Flood Zone 1, Buckinghamshire's pre-application advice required the development to follow the sustainable drainage hierarchy. Surface-water reuse and infiltration were identified as the preferred solutions, with any departure requiring technical justification. The Council also identified nearby chalk aquifers as a matter requiring further consideration. Specialist advice was consequently sought regarding the aquifer and potential implications for the basement, excavation and drainage strategy. SuDS, groundwater considerations and drainage were then coordinated alongside the structural and waterproofing design as the project developed.