Foundation Waterproofing

Our foundation waterproofing methods and on-site process

Work always starts with an on-site inspection. We examine the exterior perimeter, the visible condition of the concrete, the slope of the surrounding grade, whether or not there is a functional French drain in place and the signs of infiltration showing inside the basement. Without that diagnosis, a membrane should never be chosen. The Delta-MS membrane from Dörken — we are certified installers — is our default choice for new builds and full re-waterproofing jobs after excavation: its dimpled structure creates a permanent drainage space between the wall and the soil so water flows freely down to the French drain instead of pressing against the concrete. Expected service life is over 25 years, and the manufacturer warrants it against root puncture. Sprayed elastomeric membrane goes on as a liquid and cures into a continuous rubber-like film that follows irregular shapes — corners, rounded angles, pipe penetrations. It is our preferred option when foundation geometry makes a sheet membrane awkward to bond properly.

Liquid waterproofing membrane (Resisto, Soprema or Bakor depending on the project) is rolled or airless-sprayed in two crossed coats. It suits renovations with partial excavation, foundations where mature landscaping limits access, and added garages or after-thought footings. Tar coating remains the most affordable method and still has a place on certain jobs: targeted repairs to an older bitumen waterproofing that is still sound across 80 percent of the perimeter, or as a top-up in combination with a drainage membrane. We use it deliberately, not as a default. Whichever product is chosen, waterproofing never works on its own — it is always part of a system that includes a clean, functional French drain, a surface grade that pushes water away from the footing and, where the water table is high, a sump pump. If your drain is over 20 years old or showing signs of blockage, also have a look at our French drain service page and our new French drain installation page. For new construction, the Quebec Building Code already requires a compliant waterproofing membrane and a French drain around the footing. Our role on those projects is to do more than the minimum: choose a long-life membrane, take care of the details at corners, pipe penetrations and the joint between the membrane and the rim joist, and install the French drain properly with geotextile fabric and clean gravel. Those details are exactly where the difference shows between a foundation that stays dry for 30 years and one that starts weeping at the first hard thaw.

A typical project runs in five steps. One, free written diagnosis with photos. Two, excavation of the affected perimeter — we offer this in mini-excavation form to keep landscape damage to a minimum. Three, wall preparation: pressure-washing, brushing, filling active cracks with polyurethane or epoxy (see our crack repair page for the technical details). Four, application of the chosen membrane while respecting the manufacturer's cure times. Five, backfilling with compaction by lifts, verification of the French drain and restoration of grass or slope. Every step is documented. You receive a written workmanship warranty and keep all manufacturer product warranties. Our RBQ, APCHQ, RECQ, Réno-Maître and Delta-MS certifications are verifiable online. A quick word on the special case of concrete-block foundations, common on pre-1980 homes in Lanaudière: the mortar joints leak more readily than a poured-concrete wall, and a Delta-MS membrane combined with a liquid primer coat gives the best results in our experience. For renovations where exterior excavation is genuinely impossible — mature landscaping, attached outbuilding, neighbouring property line right against the wall — we work from the inside (cuvelage): interior under-slab drain, sealing membrane on the cold-room side, and sump pump. It is technically second-best because water still reaches the concrete, but it is a real solution when the outside cannot be opened up. On cost: as a rough guide, a targeted tar coating runs into the low thousands of dollars while a full Delta-MS re-waterproofing with excavation and a new French drain is a five-figure investment. Our free diagnosis gives you the real number for your home.