Grading and drainage are the first line of defence against basement moisture in Ontario homes. Addressing water at the source is almost always less expensive than waterproofing after the fact.
Proper Grading Standard
Grade must slope away from foundation: minimum 1 inch per foot for the first 6 feet. Settlement adjacent to foundations is common after 10-20 years and creates persistent moisture problems. Re-grade with compactable clean fill in compacted lifts — never straight topsoil (retains water). Final topsoil layer 4-6 inches.
Window Wells
Windows at or below grade require window wells. Wells must drain: connection to weeping tile or 8+ inches of clear gravel at base. Covers reduce leaf and debris accumulation.
Downspout Extensions
Extend minimum 6 feet from foundation. Underground extensions to daylight or dry well are preferred. Never connect downspouts to foundation weeping tile — roof runoff volume overwhelms systems designed for ground seepage.
Surface Ponding
No water should pond within 10 feet of foundation. French drains or surface swales address flat-lot drainage problems.
Costs Ontario 2026
Re-grade and re-sod around foundation: $1,500-$5,000. Underground downspout extension: $200-$800/downspout. French drain installation: $3,000-$10,000.
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