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Complete interior drainage systems, sealants, and sump pumps to manage water that's already entering your basement.
Interior basement waterproofing is a system of drainage channels, sump pumps, and sealants installed inside your basement to collect and remove water that has already entered through the foundation. Unlike exterior methods that block water from outside, interior systems manage water once it penetrates the walls or floor — making them the most practical solution when excavation isn't feasible or when hydrostatic pressure from Toronto's clay-heavy soil pushes moisture through the slab.
Most Toronto homes built before the 1980s have foundations that were never waterproofed from the outside. When the original tar coating degrades — which it inevitably does — water finds its way in through cracks, the cove joint where the wall meets the floor, or directly through porous concrete. Interior waterproofing addresses all of these entry points without tearing up your landscaping or driveway.
Why Choose Us
The most common mistake homeowners make is treating the symptom instead of the system. Applying waterproof paint to a damp wall or stuffing hydraulic cement into a leaking crack may stop water temporarily, but hydrostatic pressure from saturated soil will find the next weakest point within months. A properly engineered interior system doesn't fight the water — it gives it a controlled path to a sump pump that removes it before it reaches your living space.
We've completed over 1,500 interior waterproofing projects across the GTA. In nearly every case, the homeowner had already tried at least one DIY fix before calling us. The lesson is consistent: spot fixes don't work against the sustained water pressure that Toronto's freeze-thaw cycles and clay soils create against your foundation walls.
Don't Ignore the Signs
Our interior waterproofing process begins with breaking a narrow trench along the perimeter of your basement floor, directly beside the foundation wall. We install a perforated drainage channel — typically a 4-inch weeping tile wrapped in filter fabric to prevent sediment clogging — that slopes toward one or more sump pits. A primary sump pump with battery backup removes collected water and discharges it away from the foundation.
We then apply a dimple membrane along the lower portion of the foundation walls. This creates an air gap that allows any wall moisture to drain downward into the perimeter channel rather than entering your basement. The concrete floor is restored over the drain, leaving a clean finish. The entire installation takes two to four days for a standard Toronto home.
Interior waterproofing costs less than exterior excavation and causes far less disruption to your property. There's no need to dig up gardens, remove decks, or disturb driveways. The work happens entirely inside your basement, and most systems are installed in two to four days with minimal mess. We protect your flooring and belongings with plastic sheeting and use dust-control equipment during concrete cutting.
Every interior system we install comes with a transferable 25-year warranty that covers the drainage channel, membrane, and sump pump labour. We use only commercial-grade Liberty or Zoeller pumps rated for continuous duty. For Toronto homeowners, interior waterproofing is often the smartest investment — it solves the immediate problem, protects against future water events, and adds measurable value when it comes time to sell your home.
Materials & Methods
4-inch perforated pipe wrapped in filter fabric, installed in a perimeter trench along the foundation wall to collect and redirect groundwater to the sump pit.
Commercial-grade Liberty or Zoeller primary pump paired with a battery backup that activates during power outages — critical during Toronto's storm-season blackouts.
High-density polyethylene membrane with raised dimples creates an air gap against foundation walls, channelling moisture into the drainage system instead of your basement.
Active cracks are sealed with hydraulic cement or polyurethane injection before the drainage system is installed, addressing both current leaks and future water paths.
Our Process
Our technician assesses your basement, identifies all water entry points, checks existing drainage, and provides a detailed written quote with photos.
We cut a narrow trench along the foundation wall perimeter and install sloped perforated drainage channels wrapped in filter fabric to prevent clogging.
A sump pit is installed at the lowest point with a primary pump and battery backup system. Discharge lines route water safely away from your foundation.
Dimple membrane is applied to the lower foundation walls, creating an air gap that channels wall moisture down into the perimeter drain.
The concrete floor is poured back over the drainage system, leaving a clean finish. We remove all debris and restore your basement to working condition.
Client Reviews
“Outstanding job! My basement is finally dry thanks to your team. No more musty smell or moisture problems. A+ service!”
“From the initial appointment to final inspection, service was exceptional. Prompt, professional, and results exceeded expectations.”
“Professional and friendly staff. They solved our leaky basement in no time. The results were fantastic. Basement has been leak-free since the work was done.”
Experience & Expertise
Related Solutions
Reliable sump pump systems with battery backup to protect your basement from flooding and water damage.
Learn More →Professional crack injection and repair services to seal foundation cracks and prevent water intrusion.
Learn More →Comprehensive wet basement solutions combining multiple waterproofing methods for complete protection.
Learn More →Service Areas
We provide interior basement waterproofing throughout Toronto and the Greater Toronto Area.
Common Questions
