Two workers were dismantling a new log home for shipment. One was assigned to operate the crane. The other stood on the roof to hook the tongs of the crane to the structural members to be removed.

Beginning at the peak of the roof, the ridgepole was removed, followed by the filler-piece braces supporting it. The tongs were then set on the filler-piece brace below the first purlin to be removed. When the crane operator lifted out this load-bearing brace, the purlin above it - which now had no support - dislodged.

A cascade of roof member dislodgements followed, collapsing the roof. The worker on the roof was hit by a falling purlin and fell about 5 metres (16 feet) to the ground, breaking several of his ribs.

• Have written procedures or structural drawings detailing the installation and removal sequence of load-bearing members.
• Ensure workers have adequate instruction, training, and supervision in dismantling procedures.
• Use a fall protection system when a fall of 3 metres (10 feet) or more may occur or where a fall from a lesser height involves an unusual risk of injury.