Firefighters battled a blaze at a restaurant in Kennford in the early hours of Wednesday morning.
No one was injured in the incident, but the building, which was extensively damaged, was still smouldering 10 hours after the fire crews were called.
The A380, which runs adjacent to the restaurant, was closed for half-an-hour because of the fire.
Fire investigators are looking into its cause.
A hydraulic platform, water bowser and incident support unit also attended the scene.