It is not every building that can safely take a five-storey roof extension.

The so-called “flatted factory” at 55 Holloway Head is one of a handful of multistorey factories built in the 1950s to house businesses moved out of single-storey premises in parts of the city due for redevelopment.

The seven-storey blocks were built to a robust design, containing corridors and lifts able to accommodate forklifts, and super-large floorplates with a depth of 21 metres.

Now Birmingham-based Claremont Property Group has received unanimous approval from Birmingham City Council for the city’s first five-storey roof extension. The scheme involves the residential conversion of Lee Bank House at 55 Holloway Head into 122 apartments.

K4 architects designed the scheme, which reuses substantive elements of the existing structure, including the main staircases and lift shafts. There will also be space for a roof garden on top of the new roof.

“We’re looking forward to maximising the potential of the building’s structural strength to deliver Birmingham’s first five-storey roof extension,” Claremont Director Andy Robinson said. “The pandemic has reshaped our lives, so the unique configuration of this building becomes even more relevant. It will allow us to deliver much larger capacity apartments than neighbouring sites, with unusually wide corridors and private and communal outdoor spaces.”