For Residents

Minimum Grade from Foundation Walls

A sloped surface is required to effectively drain water away from the foundation walls including areas under steps and decks. This will greatly reduce the risk of surface water entering the basement during rainfalls or snowmelt.

Minimum Grade Requirements

10% for first 2 m. Minimum 20 cm drop for final landscaping.
0.75% for concrete, asphalt or other impervious surface treatment.

Grading Examples

The following pictures illustrate the proper and improper grades around the foundation wall:


Major settlement needs to be fixed	Poor Rough Grade on the right side generates a high risk of basement flooding


Negative Grade directs water to the foundation wall	A decorative hard surface could be laid onto the good grade


Major settlement under a downspout has to be fixed	Good Rough Grade drains water away from the wall	Good Final Grade drains water away from the wall without affecting the neighbouring properties


Backfill is required to fill in the area under the steps.	Improper grading around this window well may result in basement flooding.	This window well is properly graded with backfill all around.