Poured concrete foundations are the most common system used today. Concrete is poured into molds to create coffers or walls, and sometimes contain steel bars. In general, concrete walls rest on a cast-in-place concrete footing. Normally this type of foundation is seamless and resists water intrusion. It is also very resistant.

Concrete block foundations are less commonly used nowadays. They consist of masonry elements bound to one another by mortar joints. The empty space inside the blocks contains air that acts as natural insulation. This type of foundation has limited resistance to lateral soil displacement due to freeze and thaw cycles.

Fieldstone or rubble foundations were used many decades ago. The stones are bound to one another by mortar with lime as the main ingredient. This type of mortar is very permeable to moist and water, and the surface becomes friable over the years. Fieldstone foundations can be restored, but the costs involved are very high.

While uncommon today, treated wood foundations are still allowed. They require regular maintenance, and must be replaced if too deteriorated and if the damp-proof course cannot be restored.

Cracks

Cracks in concrete walls are a common occurrence in Quebec due to freeze and thaw cycles. They appear in foundations or structures of all types of buildings (commercial and residential). There are different types of cracks, each with distinctive causes and consequences.

Cracking can be the result of poor drainage, pyrite contamination, heaving due to freeze, land subsidence or poor quality soil. All these problems can aggravate if not rectified in time (water infiltration, mould growth, etc.) and can be very expensive to repair.

Why do basements flood?

Water can enter your basement for a number of reasons. This is most likely to occur during periods of heavy rainfall or when snow is melting rapidly during a spring. In these cases, basements flood for the following reasons:

• A crack in the basement walls.
• Poor lot drainage.
• Failure of foundation drains.
• Overflowing gutters or downspouts too close to foundations.

Basement flooding may also occur because of:

• A blocked connection between your home and the main sewer in the street.
• A back-up of wastewater in the sewer system (or a combination of wastewater and rainwater from the sanitary or combine sewer system).
• Failure of a sump pump (in some areas) used to pump weeping tile water.
• Improper installation of areaways.





Foundations, just like any other building structure component, require maintenance. A simple gesture can prevent basement flooding.

• Foundation drains: The best protection against moist and water resides in preventing accumulation of groundwater around foundations.
• Keep rainwater away from the foundation: the land around the house should have a 6-inch slope over a distance of 10 ft.
• Make sure that downspouts do not dump water right beside your foundation.
• Install a wall around basement windows.
• Consult a professional operating in your region

or visit: www.cmhc-schl.gc.ca