Our clients bought two flats which they wanted to restore back into a single family home. Their objective was more space, and lots of it, so that they could enjoy light-filled open plan spaces which are so ideal for contemporary family life.

The property also enjoyed the largest garden on the street thanks to being an end-of-terrace house, with enough space to spare for a standalone garage with direct access onto the adjacent road and plenty of potential for landscaping.

But how would we manage to squeeze so much out of the site without treading on the toes of the Crabtree Conservation Area?

To provide our clients with the space they desired, we would not only have to extend outwards, we would also have to extend down. Excavating beneath an existing property is always an immense structural challenge, even more so when the basement fills the entire floor plan.

Through a slow, careful process called underpinning, the contractors excavated beneath the house 1.2 metres at a time, making new supports along the way. Gradually, the space for the basement is created, with the existing building held up by brand new foundations.

The other challenge was privacy. Our client’s house sits on a prominent junction between two busy roads, which creates concern both for the council – who don’t want the street scene in the Conservation Area to be heavily impacted – and the client, who don’t want passers by to be able to stare straight into their home.

We completely filled the space between the house and eastern boundary of the garden, turning what was once a garden wall into the exterior wall of the ground floor. Matching this vast new extended space is a full plan basement below, resulting in an increase in floor space of more than 100%.

The floor plan is not unlike a slice of an Incan pyramid, with each floor above ground smaller than the one below, from the vastly extended first floor up to the two bedrooms nestled in the roof. This tapering design allows us to build as large as possible where the house can’t be seen from the street while maintaining a low profile on the floors that are visible.

While the extensions provided a transformational increase in interior space, they inevitably encroached on the garden, which is one of the property’s best features. However, by removing its two large trees and replacing them with smaller, more attractive trees and plants, we were able to make the garden feel larger than before despite its reduction in size.

Removing trees is never taken lightly, but with the advice of an arboricultural consultant we were able to gain permission for the garden trees to be removed as they were diseased and we would be compensating with the new planting at the rear of the garden and a more diverse range of plant life within.

The standout feature is one of the largest light wells we’ve ever constructed: an almost 20 square metre space which doubles as a secluded courtyard. Light-wells are often hidden away but in this case we’ve made it a statement, decorating it with greenery and lining the surrounding basement and first floor walls with matching, floor-to ceiling glass sliding doors.

A steel stairwell with a glass balustrade leads up from this courtyard lightwell up to the new timber terrace and garden (which is still a generous space, despite the extensions). Follow the path from the stairs and you reach the new garage at the southern end of the site, hidden from the rest of the house by new planting.