This proposal for a new family home, overlooking a small area of wooded nature reserve and facing southeast down the valley towards Brighton city centre and towards the sea has been an exciting design challenge. As our client’s relatively modest budget was fixed the proposals had to work hard to meet the brief, so we engaged a Cost Consultant during the early stages of the design process to make sure the proposals submitted for planning permission would be economically viable.
The existing prominent two storey pitched roof house and detached garage on a corner plot was all very tired and damp, being built into and retaining an almost vertical rear garden. The brief called for a detached low carbon four-bedroom family dwelling which is biodiverse, accessible, modern and contextual, and presents a high design standard taking advantage of views whilst maintaining privacy for occupants.
As well as developing initial design ideas we also had to explore and conclude the method of construction at the start of the design process. Meeting the spatial requirements of the brief, respecting existing building lines and outlook from neighbouring properties meant that the new house had to sit further back into the steeply sloping garden than the existing house. Building an external wall that must also act as a retaining structure, keep the ground water out and be thermally effective is technically complex and therefore expensive. An economic and ‘simple’ solution was to form independent retaining walls outbound of the house footprint on three sides, so that the external walls of the new house were not required to retain the sloping garden or keep the ground water out and therefore can be insulated to a high standard in a more simplistic way.
The proposed layout juxtaposes the existing building footprint with a south-easterly angle to optimise views and to address the street frontage more successfully than the existing dwelling and garage. The ground floor level comprises a double garage following the south-easterly angle for optimised vehicular entry, the primary entrance lobby, WC, and a games room which opens onto a small east-facing terrace. All bedrooms are at first floor with ensuite bathrooms, study, family bathroom, laundry station and rear garden access. The master bedroom suite is angled for optimised south-easterly views. The second floor is also cranked to optimise views and provides an open plan kitchen / dining / living room with access to a south-east-facing roof terrace and stepped access to the rear garden.
As with all our projects we approach sustainability not as an add-on but as integral to the design process utilising passive design principles and strategies from project inception. We call this ‘the tea cosy effect’.
For us this includes:
- High levels of thermal insulation and air tightness with limited cold bridging to the external envelope (the tea cosy)
- High levels of internal thermal mass (the tea pot and tea). This is achieved by specifying solid floors rather than timber, solid partitions rather than timber stud and solid inner face of external walls. Internal thermal mass regulates internal temperatures (a cave has a constant internal temperature no matter the season).
We also consider other passive design measures:
- Orientation – Facing the main glazed façade towards the south to increase winter warming through solar gain and limiting north facing glazing to reduce heat loss in the winter.
- Solar shading – shielding south and west facing glazing to reduce solar gain in the summer.
- Natural ventilation to achieve summer cooling. We believe homes should be naturally ventilated to provide summer cooling (energy consuming ‘air conditioning’ has no place in good design). Before presenting the feasibility proposals to our clients we undertake thermal modelling of the proposal to simulate how the building will perform during different seasons and design the size of opening windows and roof lights to ensure the building achieves sufficient air movement for occupancy ventilation and overheating mitigation.
Getting these simple passive design principles right at the early design stage significantly reduces the ‘active’ more costly sustainability measures required to reduce energy consumption of the home. We also believe that a good ‘sustainable’ building does not have to shout out about it by having every bit of technology ‘on display’.
Whilst the planning application is being determined we are pursuing the early engagement of a local Building Contractor under an ‘open book’ type contract arrangement to enable a start on site early in 2024.