How to fix a leaky basement
By Amy Brown-Bowers • Bankrate.com

"If you've got a sidewalk that's sloping in toward your house, that's just an invitation for water to come in," says Harry Cavan, who was the owner of Toronto-based The City Wide Group for 40 years.

Landscaping may also contribute to leaks in the basement, MacRae says. Planting bushes or flower beds right against the foundation without taking proper precautions is an invitation for water to collect, pool and drain into your basement.

"There's nothing wrong with having a nice little garden right up against the house, but make sure to apply some liquid foundation to the house to protect it," MacRae says.

Cracks in the foundation
Cracks in the foundation due to the gradual settling of soil are among the most common sources of basement leaks in newer homes, Cavan says.

"The trouble ... with new homes that are built in the winter is they have a habit of retaining the moisture, and then settling cracks (in the foundation) start to occur in the spring. I've seen as many as 10 or 12," Cavan says.

The cost of repairing a crack in the foundation "depends on the depth and accessibility of the crack and on what you've got to put back together," whether it's patio stones, interlocking brick or landscaping elements, says Cavan. All in all, you're likely looking at a bill of $1,500 to $2,500.

The type of foundation you have will also determine in part the cost of the repair, Daley says. "A leak in a block foundation is a whole lot more difficult to repair from the inside of the house. It has to be excavated from the outside, whereas a poured foundation is more likely able to be fixed from the inside, which costs a whole lot less," he says.

Weeping tiles and waterproofing
Weeping tiles are a common and effective defence against basement leaks. They are a four-inch perforated drain around the periphery of the house about a foot and a half to two feet lower than the basement floor, MacRae says.

"When ground water comes up, (the weeping tiles) allow cavities for that water to weep off before it gets to floor level on the inside," he says.

"Basically a weeping tile collects the residual water that migrates to the bottom of the foundation and takes that water to the street," Cavan says.

The most common causes of water leaks in basements of older homes are not having weeping tiles (they weren't installed in home until the 1950s) and having old-style weeping tiles that are prone to clogging from tree roots, Cavan says.

The cost of installing a full weeping tile system complete with waterproof membranes along the foundation costs between $15,000 and $20,000, Cavan says.

Waterproofing the above-grade parts of your foundation to protect against garden beds, sprinklers and other splashing water simply involves applying a liquid protector, which costs about $35 a gallon at any home renovation store, MacRae says. The protector can be applied like paint with a brush, roller or garden sprayer, and it provides a good seal that will keep your basement dry.

Amy Brown-Bowers is a writer living in Toronto.