Waterproofing Service in Ontario
Waterproofing covers the membranes, coatings, and drainage work that keep water out of places it shouldn't be: basement walls and slabs, foundation exteriors, below-grade parking structures, balconies, and flat or low-slope roof decks. In Mississauga, where clay-heavy soil and freeze-thaw cycles put steady pressure on foundations, this often overlaps with roofing work, especially on flat roofs and roof-to-wall transitions where leaks tend to start. We've listed 119 businesses in this category, ranging from small basement-waterproofing crews to larger contractors who handle both roofing and below-grade systems.
What the work actually involves
Interior fixes like sump pumps and interior drain tile handle symptoms but don't stop water from reaching the wall. Proper waterproofing usually means excavating to the footing, repairing cracks, applying a rubberized or bituminous membrane, and installing exterior weeping tile before backfilling. On roofs, it's about torch-on or self-adhered membranes, proper flashing at parapets and drains, and slope that actually moves water to a scupper or drain instead of pooling.
What to check before you hire
Ask for the membrane brand and warranty terms in writing, not just a verbal promise. Find out whether the crew pulls permits when excavation is involved, and whether they've handled your specific problem before (a wet basement corner is a different job than a leaking flat roof deck). Get a written scope that separates labour, materials, and any drainage or grading work, since vague quotes are where costs creep.
How we score contractors
Our ranking weighs verified reviews, licensing and insurance, years doing waterproofing specifically (not just general roofing), and responsiveness to quotes. Full details are on our methodology page. For a ranked shortlist that includes waterproofing-capable roofers, see our best roofing contractors in Mississauga guide.
Get quotes from suitable waterproofing service
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All waterproofing service, ranked by score and relevance
We found 1010 businesses offering waterproofing service; 47 met the criteria for the scored directory. The order weighs each business's overall score by how much of its reviewed work is waterproofing service, so a lower-scored specialist can rank above a higher-scored generalist. Filter and sort below, or open the full map view.
Enquiries you submit through our forms may be shared with partner providers who can carry out the work, and we may receive a referral fee. Our rankings and scores are based only on our published methodology and are not influenced by referral fees.
Common questions about waterproofing service
- How much does basement waterproofing cost in Mississauga?
- Interior drain tile and sump pump work tends to run less than full exterior excavation, since exterior jobs involve digging down to the footing, applying a membrane, and adding weeping tile. Get at least two written quotes that break out excavation, membrane, and drainage separately, since these line items vary a lot by contractor.
- How often does a basement or roof need waterproofing?
- A properly installed exterior membrane and weeping tile system is meant to last decades, often 20 to 30 years, though clay soil movement and tree root pressure can shorten that. Flat roof membranes typically need attention or replacement every 15 to 25 years depending on the material and how well drains have been maintained.
- What should I expect during an exterior waterproofing job?
- Expect excavation equipment on your property line, some landscaping disruption, and a timeline of a few days to over a week depending on foundation length and depth. A good contractor will photograph the exposed foundation before applying membrane so you can see the actual condition and repairs made.
- How can I judge the quality of a waterproofing contractor?
- Ask to see photos from a past job showing the exposed foundation and completed membrane, not just the finished lawn. Confirm they carry liability insurance for excavation work and check whether they warranty both materials and labour, since some contractors only cover the product itself.
Guides to choosing waterproofing service
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