Lot grading with substantial grade differences, from the side of the house to the rear of the house, usually occurs on walk-out basements.

Grading approval for these homes may require retaining walls at the rear corners of the house, or on the side lot. These retaining features are usually indicated on the plot plan.

The grading of the common property drainage swale must allow for 10% slope from the foundation walls of adjacent houses, and must provide drainage functionality for both properties.

Any retaining wall that exceeds 0.6 m in height, or is attached to the house, may be required to be of an engineered design. Refer to the Alberta Building Codes and Standards for more information.

The following pictures and diagram are the examples for the requirements to deal with grade differential (for reference only):

large grade differential

These 2 lots have a large grade differential

retaining wall attached to the walkout basement

A retaining wall attached to the walkout basement

This walkout basement needs retaining walls

This walkout basement needs retaining walls

This is an engineered retaining wall design example

This is an engineered retaining wall design example