What was the brief?

To create a large kitchen and dining room at the ground floor and a bedroom at the first floor.

What were the key challenges?

The client originally bought the house as they loved the bay window to the rear. The challenge was to retain this while making a bigger kitchen and improving the flow to the garden.

What were the solutions?

Moving the extension away from the rear facade of the house created a private courtyard that preserved the bay and maintained good levels of light and ventilation to the existing rear living room. We looked at a square courtyard but this constricted the width of the kitchen. The curved glass solution created more space internally and echoed the shape of the Victorian bay in a modern way. It also improved the flow through to the dining area and views to the garden beyond.

Was planning an issue?

The site is located in the Muswell Hill Conservation Area in the London Borough of Haringey. We consulted with the neighbours and the planners through a private 'Pre-app' process so that everyone's concerns were addressed before we submitted a full planning application. Through 3d modelling, we demonstrated that the project did not have an adverse impact on the neighbours and the planners welcomed the retention of the bay.

What building methods were used?

The extension is a highly-insulated timber frame clad in engineering brick at the ground floor and an insulated render system, painted dark grey at the first floor. The timber frame reduces the embodied energy of the project.
The ground floor has a screed with underfloor heating finished in a poured resin to give a seamless finish. The roof is highly insulated and finished with a 'brown roof' that will eventually be filled with wild flowers.

What do the client's think about the project?

"The results are outstanding. By skilfully configuring the former dining room into a children's' den, our growing family is able to avoid the goldfish bowl of a fully open-plan space, while still being able to come together to share the social aspects of family life; all centred around a kitchen and dining area that enjoys a view of both the Edwardian architectural masterpiece and its modern-day equivalent"

What is the energy efficiency of the project?

The existing Victorian extension had a UK SAP Energy Rating of F. The new extension, despite the large areas of glass, has a UK SAP Rating of C (74.1).
Carbon emissions per sqm for the new extension – 33.1KgCO2/sqm.
Carbon emissions per annum for the new extension – 1717KgCO2/annum.

What were the project costs?

The overall project cost is confidential.
For an extension like this you would expect to pay approximately £3,100/sqm (London, 2020 prices), excluding kitchen, fees and VAT.
The curved glass cost £19,950 including VAT.

What was the form of contract?

We carried out a tender process and prepared a JCT Homeowner Contract Without An Architect to confirm the project details clearly. Mulroy then provided ad hoc technical support and site visits as required to reduce costs.