Lot grading notes are described in the page. Lot Grading will happen because of flooding caused by heavy precipitation, melting snow, or runoff may pose problems for all kinds of properties. Older and newer houses, residential and commercial developments may be at risk for flooding if proper precautions are not taken. The municipalities encourage all builders and homeowners to take preventive measures to avoid flooding and have set out standards for drainage.
RESIDENTIAL PROPERTIES
Residential Lot Grading is shaping and grading the land to direct surface drainage away from buildings and towards a City right of way
COMMERCIAL AND MULTI-FAMILY PROPERTIES
Lot grading for Commercial and Multi-family properties is the shaping or sloping of the land in such a way that surface drainage is directed away from the buildings and controlled within the property in a manner that eliminates impact on adjacent properties and City right of ways.
Lot Grading Plan
Lot Grading Plans specify design elevations, surface gradients, lot types, swale locations, and other drainage related information required for lot grading. A Lot Grading Plan establishes the grading relationship between adjacent properties and its approval is an effective basis for the control of surface drainage.
LOT GRADING APPROVAL PROCEDURE
Lot development, including buildings, concrete driveways and walkways must be completed before applying for grading approval.
There are two stages of Lot Grading Approval. Generally, the homebuilder is responsible for Rough Grade and the homeowner is responsible for Final Grade.
The concrete pad for a detached garage or other building is elevated to provide positive slope away from the building. Finished grade elevations for pads are a design requirement and are presented on the Plot Plan that is submitted in application for a building permit. Surface drainage is directed towards the internal swale between the house and the detached garage, the side-lot swales and towards a City right-of-way. The design and the as-built elevations are shown on the lot grading certificate to support the grading inspection and approval process
- the minimum gradient on any driveway shall be 2.0%.
- the maximum gradient on any driveway shall be 7.5%.
- minimum swale depth is 0.15m
- perforated subdrain for swale should be less than 2.0%
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. Minimum grade requirements:
- Minimum 20 cm drop for soft surface/landscaping (eg. clay, topsoil or sod)
- Minimum 15 cm drop for a side yard less than 1.5 meters for both soft and hard surface grading/ landscaping
- 75% for hard surface or other impervious surface treatment (eg. concrete or asphalt) provided a minimum 15 cm drop occurs between the building and a drainage swale
Foundation grading directs surface drainage away from buildings where it is conveyed towards a right of way via common property drainage swales
