Firefighters said they arrived at the Portsmouth, England, home and found the man attempting to put out the flames with a garden hose, The Daily Telegraph reported Monday.
"The whole thing had clearly scared the life out of him," watch manager Steve Pearce said of the man. "There was a gap in the cladding where he was trying to kill the spider and so the sparks got through to the material behind and started spreading upward toward the roof."
Pearce said firefighters spent about two hours extinguishing the blaze.
"Surprisingly there wasn't much damage to the house other than to the cladding," he said. "We obviously had a chat with the man but I don't think he'll be doing this again."