Stepped and chamfered arches mark the entrance to Uxbridge Bower, an art deco annexe to a home in west London designed by architecture studio Bureau de Change.

The 30-square-metre building provides an extra en-suite bedroom for a house in Uxbridge, to accommodate the owner's mother and grandmother when they visit from their native Greece.

Bureau de Change founders Katerina Dionysopoulou and Billy Mavropoulos – who also moved to London from Greece – designed the building to reference the neighbourhood's art-deco architecture.

"The house is located in a suburb developed in the 1920s and 30s, with surprising and quirky art-deco details like stepping windows and porches, and bold geometric patterns," Mavropoulos told Dezeen.

Uxbridge Bower incorporates these motifs in its decorative structure, which is fronted by a pair of hexagonal bays that create an informal veranda.

This led the architects to describe it as "a granny annexe like no other".

"We started with a simple post and lintel structure, chamfered the connection between columns and roof, then created a zigzag stepping to the chamfer," explained Mavropoulos.

"These moves unite the two elements into one."

Colour and texture finishes emphasise the angular details, concealing a structure made from cross-laminated timber (CLT).

"We chose CLT for its sustainability credentials, but also for its speed and ease of installation," Mavropoulos explained.

The exterior surfaces are coated in a textured render, painted in a dark shade of blue, while the edges of the columns are finished in bush-hammered terrazzo.

The underside of the canopy is painted in a contrasting shade of yellow ochre.

"Art deco is often associated with bold colours and contrasts, punctuated with metallics," said Mavropoulos.

"We chose a contemporary take on this, starting with a golden ochre for the porch, which responded to the client's longing for the Greek sun," he continued.

"This bold colour reflects back into the pavilion, giving it a warm glow in all seasons."

Care was taken to ensure these details sit well alongside each other; for example, the terrazzo cladding is polished at the edges where it meets the ochre.

"This is a subtle but important detail to soften the transition between the elements," added Mavropoulos.

The hexagonal geometries of the floor plan help to minimise the scale of the structure in relation to the surrounding houses.

The bedroom suite features floor-to-ceiling glazing, with sliding doors that allow the interior to open up to the veranda.

Garden storage is also included, tucked away at the rear of the building.

The project is the latest in a series of characterful residential projects by Bureau de Change. Others include the terrazzo-filled Frame House and the tile-clad Clay House.

The photography is by Gilbert McCarragher.

Project credits

Architect: Bureau de Change
Contractor: Stec Construction
Structural engineer: Element Structures