A total of 13 fire crews were called to the blaze on Salhouse Road in Sprowston on Thursday.

The fire is believed to have started near Scandia, a building and joinery specialist business.

An investigation was launched into the cause of the fire, but an exact cause has not been determined.

A spokesman for Norfolk Fire and Rescue Service said: “Due to the extensive damage and concerns over the structural safety of the building, our initial fire investigation concluded undetermined cause."

13 crews were called to the incident on Thursday (Image: Denise Bradley)

Despite this, arson has been ruled out as a cause of the fire, with a spokesman for the fire service adding: "We have ruled out it being a deliberate ignition.”

The incident saw crews from across the county stationed at the scene for more than four hours, with Salhouse Road closed during the fire.

Locals had also been warned to keep windows and doors closed at the time.

Crews from Sprowston, Carrow, Earlham, Wroxham, Hethersett, Fakenham, Great Yarmouth, Wymondham, Aylsham, Hingham, Mundesley, Martham, Dereham, Watton, Cromer, Diss and Reepham attended.

© Norwich Evening News