The ashes had been put in the bin 24 hours after their domestic fire had died but still carried enough heat to ignite the wooden compost bin, Mr Allen said.
"A couple of young guys saw smoke and came banging on our door. If only we'd caught it 10 minutes earlier, " he said.
Firefighters contained the fire within 15 minutes, Mr Robinson said, and had used breathing gear to enter the smoke-filled shed after the structure also was found to contain sheets of asbestos. Acetylene bottles from a pair of welding plants and LPG bottles were removed and cooled in a portable dam on the front lawn and a large number of books also were discovered during the dampening down of hot-spots in the shed, Mr Robinson said.
Mr Allen said yesterday he had lost about $100,000 worth of property that included the Mitsubishi van - alone worth about $7000 - a Toyota flatbed truck, a ride-on mower, push mower, welding plants and collections of tools.
He said the van and truck, while both newly warranted and registered, were uninsured. The damage to the shed and his other property was insured.
The Mitsubishi van also was bought to help carry family and friends at a 50th wedding anniversary he and Tini will celebrate in March, Mr Allen said.
"I'd just got it all groomed up and all sparkling new, too. But we still have two cars and at least nobody was hurt.
"The lesson is to insure everything and whatever happens - you just have to get on with it." Mr Allen said.