Waterproofing covers the work that keeps groundwater, rain, and seasonal freeze-thaw cycles out of a foundation and basement. In Mississauga, that mostly means dealing with clay-heavy soil that holds water against foundation walls, aging weeping tile on homes built before the 1990s, and window wells or grading that funnel runoff straight toward the house. The category includes exterior excavation and membrane work, interior drain tile and sump pump systems, crack injection, window well repair, and grading or downspout fixes that stop water from reaching the wall in the first place.
What the work actually involves
Exterior waterproofing means digging down to the footing, cleaning and repairing the foundation wall, installing a new membrane and drainage board, and often replacing weeping tile before backfilling. It's disruptive and pricier, but it fixes the problem at the source. Interior systems (drain tile along the basement floor perimeter, tied into a sump pit and pump) are less invasive and cheaper, and work well when the wall itself isn't structurally compromised. Crack injection with polyurethane or epoxy handles isolated leaks without either of those larger jobs. A good contractor will tell you which approach fits your situation instead of defaulting to the most expensive option.
What to look for before you hire
Ask for a written scope that specifies depth of excavation, membrane brand and warranty, and whether weeping tile is being replaced or just cleaned. Get clarity on how long the crew has been doing this specific type of work locally, since soil conditions and drainage bylaws vary by municipality. Check whether they carry their own insurance for excavation work near a foundation, and whether the warranty covers labor as well as materials.
We've scored all 15 waterproofing businesses serving the area on the factors that actually predict a dry basement five years later: documented experience with foundation work, warranty terms, responsiveness, and verified customer feedback. See the full ranked guide to Mississauga renovation contractors for the complete list, and read our methodology for how we weigh each factor.
