Damage is pegged at around $500,000 after a controlled burn spread and engulfed a nearby barn southwest of Blenheim.
Chatham-Kent firefighters were called to the blaze at 19727 Charing Cross Road on Tuesday at around 1:45 p.m., after the fire got out of control and engulfed the 40ft by 60ft barn.
Fire officials said high winds caused the fire to move rapidly through the structure, and also sent black smoke across Charing Cross Road, forcing police to close the roadway.
An excavator was brought in to remove the roof after the structure collapsed, to allow firefighters to gain access to the deep-seated fire.
No injuries have been reported and the fire has been listed as accidental.