After preventing water from infiltrating the property, the second priority should be to ensure that the support of the building is strong and stable. A structure which is not strong enough to support its own weight plus the weight of water and snow that accumulates on it, is a potential danger to all who use it.
In Montreal, most foundations are made of stone or concrete. Quality often depends on the construction period, since materials have not always been good nor the expertise of those who built them consistently high. Strength and sealing are a foundations two main qualities.
It is important to know that a foundation must be able to breath from the inside in order to withdraw moisture that emerges from it. A space of one inch should generally be maintained between the foundation and any material that covers it.
The ground on which the building lies is also an important consideration. Montreal soil is a clay mat resting on the rock of a mountain which rises towards its centre. There are places where the rock is flush with the ground and others where the clay is deep. There are places where the buildings are perfectly stable and others where it is rather precarious and unstable. In between is a range of possibilities from a total peace of mind to a nervous crisis and a financial disaster. One should therefore pay careful attention to this issue when choosing a building.