Water is coming in under my garage door from the driveway during heavy rain — how do I stop it?

Garage flooding from driveway runoff is a common issue in Ottawa, particularly in older neighbourhoods like Alta Vista, Westboro, and parts of central Nepean where driveway grades have settled over decades. Even a small amount of water entering your garage can damage stored belongings, promote mould growth, and compromise the concrete slab.

Why This Happens

The most common cause is that the driveway surface has settled or shifted so that it now slopes toward the garage rather than away from it. In Ottawa, decades of freeze-thaw cycling — our soil moves every single winter as temperatures plunge to -25°C or colder and then rebound — gradually changes surface grades. Leda clay, found across much of the Ottawa region, is particularly prone to settlement. Even a grade change of 1-2 centimetres can redirect water flow toward your garage.

Immediate Fixes

A rubber garage door threshold seal is the quickest and cheapest defence. These adhesive-mounted rubber strips create a raised barrier at the door opening, blocking water up to about 3 cm deep. They cost $50 to $150 for materials and take an hour to install. However, they're a band-aid — they don't solve the underlying drainage problem and can be torn off by a snowplow blade or shovel.

Effective Long-Term Solutions

Trench drain installation directly in front of the garage door is the most reliable fix. A channel drain set into the concrete apron intercepts water before it reaches the door. Cost: $2,500 to $5,000 in Ottawa, including concrete cutting, channel installation, and connection to a discharge pipe.

Driveway re-grading addresses the root cause. If the entire approach has settled, an asphalt overlay that restores proper slope (minimum 2% grade away from the garage) costs $1,500 to $4,000 depending on the area. For concrete driveways, mudjacking or polyurethane foam injection can lift settled sections for $1,000 to $3,000.

Garage floor slope correction — in some cases, the garage slab itself has settled toward the door. A concrete overlay or self-levelling compound that creates an interior slope toward a floor drain (if you have one) can complement exterior fixes.

Winter Complications

In Ottawa, the worst garage flooding often happens during mid-winter thaws or spring melt when snow piled along the driveway melts faster than it can drain. Ice damming at the garage entrance traps water. Keeping the area immediately in front of the garage door clear of snow and ice during thaw events is essential, even if you have drainage installed.

Get in touch with experienced local contractors through Ottawa Driveways who can diagnose whether your issue is a grading problem, a drainage problem, or both.

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