The £1.4 million, eight-unit block was designed with a ‘fabric-first’ approach inspired by Passivhaus principles
Located on a prominent corner site in Croydon, south London, the 514m² scheme consists of eight one- and two-bedroom apartments. One of the flats has been located at ground level to provide a fully accessible home.
Despite the tightness of the plot, each residential unit has a private external area in addition to a series of landscape spaces.
Taking inspiration from the massing and tones of adjacent Edwardian housing, the form of the scheme brings two distinct materials together: brick and metal. As a result, the key elevations are clad in brick, wrapping a super-insulated steel frame.
The massing steps back at the upper storeys to sit in line with eaves and ridge lines on the street – the change in material responding to neighbouring roof aesthetics.
The housing incorporates ’fabric-first’ sustainable principles including a super-insulated external envelope, triple-glazed windows and mechanical ventilation heat recovery.
Chalkhurst Court is the realisation of the client’s ambition ‘to create a sustainable development on this prominent corner site’ in this suburb of south London. The client, Elysian Properties, is a local developer who has a real interest in providing increased housing needs in a responsible way.
Our concept draws on the surrounding rhythms and hues of the neighbouring semi-detached houses and the locally listed church opposite to create an eight-unit apartment block on the site of a detached dilapidated house. We carried out careful analysis of the façade patterns running along the street to make sure that the building sits comfortably in its setting.
The most prominent elevations are clad in brick which wraps the super-insulated steel frame to present a public face that blends well with its environment. To achieve the eight units on the tight site, we developed a massing strategy that steps back at the upper floors in line with the predominant eaves and ridge lines on the street, with a change in material to respond to the surrounding roof aesthetic.
To achieve the complex form and at the same time meet the stringent sustainability requirements set out as part of the planning permission was one of the key challenges for us. As a response, the building is a steel frame entirely wrapped in high-performance insulation which runs right under the concrete foundations to remove all cold bridging. This is combined with a robust airtight barrier and triple-glazed windows as part of a fabric-first approach to the design. We worked closely with Passivhaus consultants Etude as the design developed. Their key role ensures that the sustainability strategy was developed in parallel with the design from the outset. A combined air-source heat pump and mechanical ventilation heat recovery (MVHR) unit supplies each apartment with a highly sustainable heat and hot water source.
Chalkhurst Court demonstrates how we can ‘densify’ our suburbs sustainably while remaining sensitive to the surrounding low-rise context.
Start on site October 2017
Completion March 2019
Gross internal floor area 514m²
Gross (internal + external) floor area 835m²
Form of contract or procurement route JCT Intermediate Building Contract with Contractor’s Design 2016
Construction cost £1.4 million
Construction cost per m2 £2,490 (excluding landscaping)
Architect Tate Harmer
Client Elysian Properties
Structural engineer Engenuiti
M&E consultant Etude
Passivhaus consultant Etude
Landscape consultant Adams Habermehl
Project manager Tate Harmer
CDM coordinator HK Safety Services
Approved building inspector Assent Building Control
Main contractor Cobalt Green Construction
CAD software used Revit
Annual CO2 emissions 6.4 tonnes
Airtightness at 50pa 4.0 m³h/m²
Heating and hot water load 32 kWh/m²/yr
Design life 60 years