Architect Stephanie Thum-Bonanno has added a stepped brick extension to her east London home, introducing vertical oak fins that frame views out to the garden.


For her first solo project, architect Stephanie Thum-Bonanno took on the renovation and extension of her own home, a Victorian terrace in need of modernisation. She extended from the side, rear and loft of the house to maximise space and improve the connection to the back garden.

Owing to height limitations, the extension is sunken into the ground and has a stepped formation resulting from the decrease in floor plate towards the top. A bathroom is relocated from the rear to the side of the house at ground level to open up access to the garden, while three ensuite bathrooms are added to the two upper levels.

Vertical oak fins punctuate the floor-to-ceiling glazing of the extensions, directing views out to the garden from the kitchen, a Japanese-inspired bathroom and loft bedroom. The fins offer some shade to the southeast-facing façade and privacy for the ground floor bathroom, which features a Japanese cypress tub inspired by the architect’s travels in Japan. “Being part Japanese, I developed an interest in Japan as a teenager. Working at SANAA gave me the opportunity to live in Tokyo and from then I fell in love with the country and started travelling to different regions,” Thum-Bonanno told Architecture Today.


“The existing house suffered from awkward circulation and a poor relationship with the garden,” says Stephanie Thum-Bonanno, an architect at London practice Delvendahl Martin, who has also worked worked at SANAA in Tokyo and Piercy & Company in London.

“It was important that the kitchen has a strong connection to the garden. Vertical oak fins on the rear elevation frame views out to the garden.”

A “simple and calm material palette” is deployed throughout the interior. White-oiled oak joinery and polished concrete are paired with pine floorboards retained from the existing house and used to create spaces that are bright, fresh and organised.

“The allowance for ample storage space helps keep the space clean. The detailing, such as the recessed cupboard handles, is minimal, whilst the use of timber helps bring warmth to the space,” said Thum-Bonanno.

The upper floors are connected by a pair of curving wood-lined staircases that draw the tones of the oak from the fins and extensive kitchen cabinetry up into otherwise white bedroom levels. The first floor landing is spacious enough to accommodate an informal study adjacent to a garden-facing window, which has been handy for working from home during the pandemic.

“I actually designed the project the year before the pandemic and so didn’t anticipate that we would both be working from home as soon as the project was completed! Once the project was completed, we were both grateful to have our own space to work from,” said the architect.

On the uppermost floor, comprising a bedroom and ensuite bathroom, the fins have been blackened to match the dark cladding of the dormer extension.

“In contrast with the natural finish on the ground floor, the fins at loft level are stained black, so the extension reads as part of the roof form,” explains the architect.

Additional images and drawings