Foundation Waterproofing near you

The National Building Code distinguishes two levels of protection. Dampproofing, a coating that resists moisture moving from the soil into the wall, is required on the outside of foundation walls below ground wherever the ground outside is higher than the basement floor. Waterproofing, a true barrier against water, is required where hydrostatic pressure occurs, meaning where water can build up and push against the foundation. Many older houses were built with only a thin dampproof coating, and exterior foundation waterproofing replaces it with a real membrane.

A membrane keeps water off the wall; the French drain, or weeping tile, carries it away. It's a perforated pipe laid around the footing, bedded in clean stone and wrapped in filter fabric, that collects water from the soil and sends it to a storm sewer connection or a sump pit. Without a working drain, water collects at the bottom of the wall and finds its way in at the joint between the footing and the wall.

Older houses often have clay tile or early plastic drains that are clogged with silt, invaded by roots or crushed, and some were never connected to anything useful. In parts of Quebec, iron-rich groundwater can also coat drains with a reddish sludge known as ochre. A camera inspection of the existing drain, through a cleanout or the sump pit, shows whether it can be cleaned or has to be replaced, and your municipality decides where a new drain may discharge.

Exterior waterproofing is usually done between spring and fall, once the ground has thawed and dried enough to dig safely. Frozen ground makes the work slower and harder, and an open trench caught in a heavy rain fills with water and mud. Contractors' schedules tend to fill up after a wet spring, when many homeowners discover leaks at the same time.

Expect disruption along every wall being done: a trench beside the house, piles of soil on the lawn, machinery on the driveway and sometimes a stair, a patio or a flower bed removed and rebuilt. Shrubs planted against the wall may not survive, and a deck or a concrete step often has to come off to reach the foundation behind it. Ask for the restoration to be spelled out, down to what happens to plantings and paving stones, and sort out access early if the neighbouring house is close, since the crew may need to work on or cross the neighbour's lot.

Many municipalities require a permit for excavation and foundation work, especially when drains are reconnected, exterior insulation is added or the work reaches the sidewalk or street; check with yours before the job starts, and expect the contractor to handle the application.

Nobody should dig next to a house before buried lines are marked. In Quebec, the Régie du bâtiment du Québec tells contractors to file a free locate request with Info-Excavation at least 4 business days before work begins. In Ontario, requesting a locate through Ontario One Call is free and required by law, at least 5 business days before digging. Private lines, such as a gas line to a barbecue or wiring to a shed, aren't covered by these requests and have to be located separately, so tell the contractor about any you know of.