A former care home was left engulfed in flames after it was deliberately set alight, prompting a warning about the summer rise in deliberate fire-starting.
Around 30 firefighters were called to the building in Frinton-on-Sea in Essex on Saturday evening, Essex County Fire and Rescue Service said.
When crews arrived at the former care home in Connaught Avenue at 4.48pm, they found a fire in the roof.
Initial reports suggested there may have been people inside the building, but a search by firefighters found it was empty.
Nearly half of the building - around 40% - was destroyed by the blaze, the service said.
Station Manager Nick Singleton said: "Our crews did a sterling job to stop the fire from spreading to the whole building, working in arduous conditions."
Essex Fire and Rescue Service said Two crews will remain at the scene this evening to continue dampening it down.”
The cause of the fire is thought to be deliberate.
Essex Fire & Rescue Service said they typically see an increase in deliberate fires during summer months and urged local residents to use FireStoppers - an anonymous way to report information on deliberate fires managed by CrimeStoppers - to report information that could prevent a fire from occurring.