Five fire engines rushed to a house blaze next door to a secondary school on Thursday afternoon.
Police were also called at 1.15pm to the fire in Castle Street, Berkhamsted, next door to Berkhamsted School.
Firefighters discovered the ground floor of the end of terrace property well alight.
They used a hosereel jet and breathing apparatus to tackle the fire.
Police closed the road while the fire was dealt with.
The flames were out by 1.35pm but firefighters remained on the scene to dampen down.
The cause of the blaze has been logged by the fire service as accidental.