Proper lot grading is vital for the long term health of your home. Often, during year end warranty inspections I find lot grading issues that are difficult to repair. Plus, builders often dump gravel between homes before the grading ( swale ) is done properly. These problems contribute to chronic moisture conditions caused by water leakage and dampness through the basement foundation walls. This can also contribute to sump pump failures, sewer backups, ponding on your lot, and foundation settlement issues.
The basics are simple. The lot grade must always slope away from your home without negatively effecting the adjacent home. In between homes, there must be a V-shaped "swale" that directs water away from both homes to the front or to the rear of the home. This V-shaped "swale" must be well defined before the gravel is placed between the homes.
As well, the Ontario Building Code requires that your foundation must extend not less than 150 mm or 5 7/8 inches above finished ground level. This keeps siding, bricks, stucco and other similar materials above grade.
Often during inspections the slope of the lot grading is towards the house, yet only a few inches of foundation is visible above grade. This creates a huge problem because the simple fix, adding soil near the house and sloping the lot away from the house, is now not possible. In cases like this the whole yard should be re-graded to fix the problem.
All I can say is this -
1) Don't allow your builder to dump gravel between your homes unless there is a well defined V-shaped swale directing water away from both homes towards the front or rear of the lot.
2) Don't allow your builder to lay sod down unless you can see that the lot is graded in a way that will direct water away from your home without negatively effecting other homes.
3) Don't allow your builder to grade too high up on your foundation wall. You must be able to visually see a minimum 5 3/4 inches of your foundation walls.
4) Before your builder installs the window wells, confirm that the weeping tile ( a black pipe full of gravel ) is exposed and under each basement window.
5) Don't have your A/C systems installed until after the lot grading has been done. This will interfere with the people doing the lot grading and create a low area under and around the A/C unit.
Andy Shaw - 905 876 4761
Halton Home Inspection Service
