The acceptable as-built tolerances from the approved grades are (provided minimum slopes are achieved):
- Between 0 cm and -10 cm below final grade for topsoil (black dirt). "0" is at approved design grade.
Example: Design Grade is 682.25 m and Existing Grade is 682.20 m, that is 5 cm below design grade.
- Between -10 cm and +10 cm below or above final grade for finish landscaping (sod or concrete).
Example: Design Grade is 682.25 m and Existing Grade is 682.30 m, that is 5 cm above design grade.
Note: For decorative rock, washed rock or wood chips, the surface elevation below that materials must be within the tolerance.
The lot grading inspector has discretion to accept elevations that are not within tolerances when the following conditions occur:
- The landscaping is graded to match an existing fence, walkway, lake, park, curb, sidewalk, road or lane and there is no impact on the surface drainage.
- The landscaping is graded to match an adjacent property and it appears to the Lot Grading Inspector that there is positive on-site surface drainage.
- A proposal is submitted to revise the design elevations on the approved Lot Grading Plan (Surface Drainage Plan) to existing elevations, providing that there is no negative impact on surface drainage and any affected property owners agree to the red-line revision.
Note: In cases where existing conditions make it difficult to achieve design tolerances, such conditions must be brought to the attention of the parties affected and the Lot Grading Inspector. Where changes have been accepted, those changes must be noted on the Lot Grading Inspection Report and stamped on the Lot Grading Certificate (As-built Plan).