Grading near you

A good contractor starts by reading the existing grades with a laser or builder's level and walking the lot during or after rain, so the new slope ties into the street, the neighbours and any swales. Sod and topsoil are stripped where the grade will change. Next to the foundation, the build-up is usually a dense, less permeable fill that sheds water, placed in thin layers and compacted, with a cap of topsoil for planting. Loose sand, mulch or wood chips piled against the wall do the opposite and let water straight through.

The finished grade must fall away from the house on every side, as the Government of Canada's property grading guidance describes, while leaving a gap below siding, wood framing and window sills. Where raising the soil would bury a basement window, the window well is extended rather than the problem moved. The job ends with sod or seed, and a good contractor checks the result after the first heavy rains.

When a house is built, the soil pushed back into the excavation around the foundation is loose, and it keeps compacting for years. A slope that looked right on move-in day can slowly turn into a shallow channel along the walls that collects water rather than shedding it. Trenches dug later for water, sewer, gas or irrigation lines settle the same way.

Other causes build up over time: frost heaving walkways and slabs, tree roots and old stumps rotting underground, and years of landscaping that raised beds and borders without thinking about where water goes. In many cases, topping up and reshaping the problem areas is enough. A full regrade makes sense when the whole lot drains the wrong way or new features have changed the flow.

In many newer subdivisions, each lot was built to an approved grading plan, and the swales that run along property lines are part of a drainage pattern shared by several homes. Clarington, Ontario, for example, tells new homeowners not to fill in or change the drainage swales on their lots, because doing so affects their own drainage and their neighbours', and notes that permits for decks and pool enclosures may wait until the developer's engineer has certified the lot grading. Before building a shed, a raised bed or a fence footing across a swale, check the plan with your municipality.

Bringing in or removing soil can also fall under a municipal site alteration or fill by-law. Clarington's Site Alteration By-law 2024-017 requires a permit before anyone places or dumps fill or topsoil, removes soil or alters the grade, and it doesn't allow fill brought in from outside the municipality. Other cities have their own versions, with different permits and exemptions. The Government of Canada's grading guidance gives the same advice: ask your municipality before changing a lot's grading, and never send water onto a neighbour's property.

Even shallow grading can reach buried lines, because gas, power and communications services often run close to the surface near the house. In Ontario, a free locate through Ontario One Call is required by law at least 5 business days before digging, and in Quebec the RBQ asks contractors to request a free locate from Info-Excavation at least 4 business days ahead. Private lines to a garage, shed or outdoor lighting have to be found separately.

Grading is best done once the ground has thawed and dried out. Wet soil can't be compacted properly and turns to mud under equipment, frozen soil can't be shaped, and new sod needs a few weeks of growing weather to root before winter. Spring melt and heavy rain are the best times to watch how water really moves across the lot, so photos from those days help the contractor plan.