Mitchell and Corti architects have extended and reinvented a terraced house in the heart of a London conservation area and it couldn’t be more sustainable. This net-zero carbon residential retrofit project proves that a seamless integration of sustainable systems is possible without compromising on aesthetics. From its inception, this side, rear and loft extension project set out to achieve ambitious sustainability, airtightness and energy targets: it now boasts a remarkable A-100 energy rating, external blinds, solar panels, an ASHP, MVHR air handling unit, triple glazed windows/doors, wildflower roofs, reclaimed tiles, natural clay walls and much more.
The project is the result of immense efforts put in by a forward-thinking client, a challenge-keen architect, and tireless contractor, to prove what seemed impossible: making a Victorian terrace house energy self-sufficient whilst maintaining the external appearance of a traditional period home. The combination and use of natural materials creates a unique and timeless aesthetic which does not give away its surprisingly sustainable credentials. The house now achieves a 90% reduction in carbon emissions and an 80-90% reduction in consumption of kWh per year. The remaining energy supply is provided by the client’s shares in a wind turbine, making the project a net zero energy home.
Conceived as a family home with a difference A-100 house strives to reduce its impact on the environment by using a wide selection of sustainable materials and technology. The house is not compromised in terms of natural light, the size of openings is generous but strategically placed, and all living spaces look onto planted/green spaces. At the same time, it is quieter than any of the neighbouring houses and benefits from an almost constant internal temperature year-round. Bright and quiet, with interiors that alternate between bold colours and paired back finishes, every corner of this home has been carefully designed and crafted. Solid oak skirtings and architraves surround the full height oak veneered doors and complement the oak veneered plywood joinery, characterised by slender timber dowel details.
From the very first concept sketches the design included an extension with a deep south facing façade, 500mm thick external walls to allow for generous amounts of insulation, set back windows to reduce the amount of solar gain, a planted lightwell and wildflower roofs to encourage biodiversity. The external shutters are concealed within the facade, electric integrated blinds with plaster over frames cover the most exposed skylights, a water butt collects excess water from the roofs, thick wood fibre insulation finished in a natural lime plaster the walls and an air source heat pump, solar PV panels and MVHR fuel the home.Nestled in the heart of Queens Park conservation area lies this mid-terrace family home. From the street A-100 House looks no different from its neighbours.
Mitchell and Corti architects were appointed by the client to assist them in extending and renovating their existing Victorian property in order to create a light filled home which could be as sustainable and environmentally conscious as possible, without compromising on the overall look and feel..
The original house lacked insulation and was powered by 2 boilers, resulting in a carbon footprint larger than that of most houses this size, whilst the interior décor and internal layout left a lot to be desired.
In order to mitigate solar gain issues, the south facing extensions are subdivided into tall narrow openings each framed by deep brick reveals with an overhang to create some natural shading. This exterior treatment also informs the architecture throughout the house, carrying through the language of tall vertical elements such as solid oak dowels that cut through the made to measure shelving units and the over three-meter-high doors on the ground floor.
The side elevation features a full-length slot window overlooking the extension, home to one of two wildflower roofs, currently in full bloom with carefully selected native flower species. The outlook from the kitchen and bedrooms rather than onto a roof is now on a variety of flowers and grasses, designed to change with the seasons.
The loft dormer extension is clad in GreenCoat PLX, one of the most sustainable metal cladding products available on the market. Concealed within the overhanging fascia are electric shutters introduced to mitigate solar gain and heat variation throughout summer. The shutters are combined with wood fibre roof insulation, that has a much higher density than a standard PIR, making the internal temperature more constant during the winter, to ensure a comfortable use all year round.
From the front entrance door to the top of the loft, the wall is clad in Clayworks Clay plaster, a Cornish product that absorbs moisture from the air aiding to balance internal air quality whilst all other walls are finished in a breathable lime plaster, creating a base palette of soft, honest and raw materials.
The interiors of the house are defined by a bold combination of natural, recycled and reclaimed materials ranging from 100-year-old reclaimed Spanish tiles in the ground floor WC, to reclaimed front garden tiles and rear patio pavers, to joinery made from a material manufactured by Smile Plastics using recycled chopping boards and food trays to create a marble-like bar unit.
Team:
Architecture & Interior Design: Mitchell + Corti Architects
Structural Engineer: Mitchinson Macken
Photographer: Luke Weller
