Alexander Martin Architects has added a three-storey extension to a Victorian house in north London, featuring brick walls and a big window facing out to the garden (+ slideshow).

The addition to a home in the city's Crouch End neighbourhood was designed by Alexander Martin Architects to replace a two-storey extension that failed to create an appropriate connection between the original rooms and the garden.

"The design emerged from issues with efficiency and connectivity within the original layout," explained Martin, whose previous projects include a loft conversion with a study hidden behind a moving wall.

"The new extension is an integral addition to the original building, whereby rather than remaining as a detached space, it maximises the circulation of the overall house plan whilst adhering to floor levels dictated by the existing landings."

The house is situated in a conservation area surrounded by an eclectic mix of buildings, which influenced the decision to create a contemporary structure. But brickwork facades were added to echo the materiality of the original property.

"The locale hosts a distinct mix of building styles," the architects explained. "The ambition was to imbue the relationship between the existing and proposed with a palette of these contradictions and harmonies."

In addition to the red brickwork cladding, a zinc-clad roof and matching openable window sections in painted timber contribute to a material palette that is expected to age attractively over time.

A door introduced at lower ground-floor level provides an additional entrance that opens onto a corridor leading towards the new kitchen and dining area.

This space adjoins existing living areas, including a study and family room. The aim is to enhance circulation between the old and new parts of the house, but also to allow activities to spill out onto the rear garden.

Stairs off the entrance corridor ascend to the first floor, which accommodates an open-plan dressing area and bathroom for the self-contained master suite that occupies the extension's upper levels.

A cantilevered oak staircase leads from the bathroom to the bedroom on the top floor, which opens onto a terrace overlooking the garden.

The interior palette is simple and muted, with exposed ceiling joists and the frameless windows enhancing the sense of space throughout the extension.

Full-height windows on each level ensure the rooms are filled with natural light and views of the surrounding neighbourhood.

Other recent extensions to traditional London properties include a sunken glass box added to a 19th-century home, and a pair of small additions to a brick terraced house that contain a study and shower room.

Photography is by Peter Cook.