Since July, foundation repair crews have been working nearly every day to keep up with the demand.
"I am in this business for 25 years right now and I think it is the worst year that we had. Thousands of houses that are sinking right now in Montreal and surrounding," said Martin Thiboutot, a foundation specialist.
The sinking has often been associated with homes on the Plateau, but it is also affecting buildings in the city's east and west ends as well as areas off the island like Brossard and Repentigny.
It is caused by drying out of ground under the foundation, which creates pockets of air. The weight of the house then forces the house to sink, causing cracks.
Experts also say heavy truck traffic can speed up the breakdown.
The average cost of such repairs can vary between $50,000 to $100,000.
Large steel piles must be inserted down to the bedrock and pinned to the foundation to keep it from sinking any lower.