Architecture practice THISS Studio has reconfigured the dark interior of an interwar house in east London, adding an extension characterised by timber joinery and a curved aluminium roof.

Designed to have "a fun and unconventional presence", the extension was conceived by THISS Studio as though it were a piece of furniture rather than a conventional structure.

It is formed of exposed timber joinery animated by a curved roof canopy, affectionately referred to by the clients and studio as the "fried egg", giving the project the name Sunny Side Up.

"We wanted to create a fun and unconventional presence in the garden that also reflected [the clients'] playful character as people," THISS Studio told Dezeen.

"We wanted to think of the new addition at a domestic scale and more like a piece of furniture that you can sit within and enjoy, rather than a typical extension of the existing spaces," it continued.

"In doing so we were forced to consider the materials and how they came together much more than you normally would, as every joint and intersection was exposed."

Sunny Side Up expands the home's ground floor by three metres and contains a light-filled dining space. Its design evolved from the client's original vision of a full-width rear extension.

By reducing its size, more of the client's budget was allocated to using sustainably sourced sapele hardwood for the timber structure.

Sapele wood has also been used to create a lattice structure below a large skylight, which sits above the dining table, as well as a built-in bench seat.

To protect the exposed timber structure from the elements and create shade during the summer months, the sweeping aluminium canopy extends from the back of the home to rest above the extension.

The roof was laser cut into its unique organic shape and is also designed with a gentle slope to direct rainwater away to a rain chain.

"The garden is south-facing and gets a lot of direct sun in summer, so the canopy acts as an external sun shade to give a bit of respite when the sun is at its hottest," said the studio.

"Generally exposed timber doesn't like the sun too much even if treated, so the canopy protects it from degradation and increases the lifespan of the building considerably," added the studio.

"It also protects the timber from the rain too, leaving it dry and protected pretty much all year round."

Inside, the Sunny Side Up project also involved an update to the original kitchen.

It features Italian terrazzo worktops and splashbacks, paired with dark slate flooring that continues out to the sunken patio.

According to THISS Studio, the garden was treated as "another room rather than a separate space" in the project. It was landscaped by the client and his mother who is an experienced landscape gardener.

Views of the garden are captured through the sapele-framed windows and bi-folding doors, while a servery window allows food and drink to be served from inside to out, further supporting this connection.

Using wood as the dominant material is becoming increasingly popular in residential extensions.

Elsewhere in London, O'Sullivan Skoufoglou Architects recently used the material to line the interior and exterior of an extension, while Emil Eve transformed a terrace home with  fir.

The photography is by Jae W V Kim.