A Calgary contractor has been fined $15,000 in connection to roof collapse at a seniors’ facility in April 2011.

Canterbury Roofing was convicted Thursday of a provincial safety code offence for creating an "unsafe condition" after a pallet of building materials placed on the roof at Clifton Manor crashed through the roof and into the dining room where lunch was being served.

Kitchen staff and about 15 elderly residents were in the room just moments before, but were rushed out when they heard cracking noises.

No one was injured.

"This is a very serious case, and we are very fortunate that the kitchen staff acted quickly for the safety of residents," says Kevin Griffiths, manager of building regulations and chief building official at the City of Calgary.

"We will continue to prosecute such cases to send a clear message that construction site safety in Calgary must be taken seriously."

Judge Paul Mason of the Provincial Court of Alberta imposed the maximum penalty fine of $15,000 for a first offence allowed under the Safety Codes Act.

The court found Canterbury failed to take the necessary steps to ensure that the roof of Clifton Manor could sustain the weight of the roofing materials.

The pallet that went through the roof weighed roughly 1225 kilograms.

Canterbury Roofing declined to comment Thursday.