Extension to bomb-damaged Victorian house creates a private oasis

Can you briefly describe the project?

As well as repairing and restoring the original Victorian home (much damaged by neglect, historic bomb damage and tree-root subsidence), the project aimed to create an unexpected and generous new rear extension which would reconnect the house to the wide south-facing garden. The works also included a new roof dormer and lowering the basement to create additional rooms.

Who is the project for and what was the brief? 

The project was for owners Emma Dahlman and Nick Illston, who were also the interior designer and contractor. They initially intended for the project to be a property development but, as the work progressed, they decided to keep the house for themselves.

Were there any significant factors that influenced the design?

The outline of the extensions was informed by a combination of permitted development and Hackney Council planning guidance, working within permitted massing diagrams to maximise their size.

The original building is generous, and it was important that any new additions stood up to its scale. The design of the ground floor extension evolved into two distinct volumes, one wide and one tall, that stepped away from one another in plan and section to create separate but connected interior spaces.

Can you explain the structure and external treatment?

On the ground floor, we inserted a cruciform concrete structure into the heart of the house, to prop up the rear wall and form the backbone of a new extension. Stepped openings and split levels mediate between the original house and the garden, forming a series of surprising and generous living spaces, held together by the expressed concrete structure.

Externally, the double-skinned brickwork acts structurally, supporting the pre-cast concrete lintels, which in turn support the expressed oak beams.

Our aim was that the structural solution to repair the building and support the extension would be clearly legible and directly inform the architecture.

How have the interiors been finished?

The expressed structure on the ground floor informs the language of the interior design, which plays with variations in texture. For example, the oak from the roof structure is carried through into the kitchen design and choice of furniture, while polished power-floated concrete floors sit alongside the rough in-situ concrete walls and beams.

In the Victorian portion of the house, we wanted to restore and retain the original features while avoiding the dark, gloomy atmosphere of the original building. As a Swede, the client/interior designer was familiar with the traditional method of treating wooden floors with lye and white oil, and this was used to create warm tones underfoot. The walls follow this theme, featuring soft and light colours.

What was the approach to sustainability?

Restoring a much-damaged historic property ensures that it can be enjoyed for future generations, while elevating its services and energy performance. Long-life loose-fit principles have informed the design and plan layout, creating open and flexible living spaces that can be easily adapted to the changing needs of current and future occupants without requiring significant construction work. The necessary and durable structural work ensures that the existing building is protected for future generations.

Thermal improvements include using a highly insulated cavity wall and roof construction for the new ground-floor extension, retrofitting insulation to the existing building, and switching to electric heating, supplied by renewable energy suppliers and PV panels.

In addition, rainwater is collected from the roof and used for watering the garden.

What was the main challenge of the project? 

Probably the biggest challenges came during construction, in particular casting in-situ concrete on a tight site. There was always an understanding that it would not be possible to create perfect concrete in these conditions, so we decided to go the other way, celebrating the roughness of the casting process using rough formwork and avoiding repairs to pitted surfaces.

What is your favourite moment in the project? 

I am really pleased with how calm and composed the rear spaces feel. The concrete and timber beams help to absorb sound and provide a surprisingly soft acoustic quality, helping to quieten the space and create the sense of a private oasis that is so removed from the London street.

Client and interior designer Emma Dahlman’s favourite aspect is ‘…how well we've managed to make the extension connect to the Victorian part of the house. It's such a contrast but at the same time they are made for each other.’

Are there lessons from this project which might be applied elsewhere?

We love concrete as a material, and increasingly prefer to embrace the unpredictability of the casting process rather than striving for perfection. We think this approach can be applied to other materials and on other projects. As long as the unexpected is contained and complemented with more precise moments, this can be a more joyful and exciting way to approach construction.

George Dawes is co-founder of Bindloss Dawes

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