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Seals your basement walls and floors from the inside to stop water infiltration and prevent moisture damage.
In our 20+ years waterproofing basements across the GTA, interior basement waterproofing is the solution we recommend most often for Toronto homeowners dealing with active water intrusion. Why? Because Toronto sits on heavy Leda clay soil — a glacial marine deposit that expands when wet and contracts when dry. This constant movement creates hydrostatic pressure against your foundation walls, and in many cases, the most practical and cost-effective way to manage that water is from the inside.
Why Choose Us
The core of any interior waterproofing system is a properly installed interior weeping tile (perimeter drainage system). We jackhammer a narrow trench along the inside perimeter of your basement floor, lay 4-inch perforated PVC pipe bedded in 3/4-inch clear gravel, and slope it toward a sump pump pit. We then pour new concrete over the trench, leaving a small gap at the wall-floor joint so water seeping through the foundation gets intercepted and channeled to the sump before it ever reaches your floor. This is the approach recommended by the Ontario Building Code (OBC Section 9.14) for managing subsurface water in residential foundations.
Don't Ignore the Signs
For wall protection, we apply a cementitious crystalline waterproofing compound — products like Xypex or Krystol — that chemically react with moisture in the concrete to form insoluble crystals deep inside the pores and capillaries. Unlike paint-on sealers that peel within a few years, crystalline waterproofing becomes part of the concrete itself. On top of that, we install a dimpled drainage membrane (such as Platon or Delta-MS) against the wall, which creates an air gap that directs any residual seepage down to the weeping tile. Finally, a 6-mil or thicker polyethylene vapor barrier controls moisture migration and humidity — critical in Toronto basements where summer humidity regularly pushes past 70%.
We've seen hundreds of Toronto homes — particularly the 1950s-1970s housing stock in areas like Scarborough, Etobicoke, and North York — where the original clay or concrete drain tiles installed during construction have collapsed, been crushed by root intrusion, or silted up after 50+ years. In these situations, interior waterproofing is often the smarter choice over exterior waterproofing because it avoids the expense and disruption of excavating around a mature property with established landscaping, driveways, and decks. Our interior systems carry a 25-year transferable warranty and are engineered to handle Toronto's seasonal freeze-thaw cycles and spring snowmelt surges.
One thing we always tell homeowners: interior waterproofing manages water — it doesn't stop it from reaching the foundation. That distinction matters. If you have severe structural cracks or deteriorated foundation walls, you may also need foundation crack repair or exterior remediation. During our free inspection, we do a full moisture assessment with thermal imaging and moisture meters to determine exactly what your basement needs — no guesswork, no upselling.
Materials & Methods
4-inch perforated PVC pipe laid in a bed of 3/4-inch clear gravel along the interior footing, sloped to a sump pit. The trench is covered with new concrete leaving a controlled gap at the wall-floor joint to intercept hydrostatic seepage before it surfaces.
Cementitious coatings like Xypex or Krystol applied to interior walls that react chemically with moisture to grow insoluble crystals inside concrete pores and micro-cracks, providing self-healing waterproofing that becomes part of the concrete matrix.
High-density polyethylene sheets (Platon, Delta-MS) with raised studs installed against foundation walls, creating a continuous air gap that channels wall seepage downward to the weeping tile while allowing the concrete to breathe.
6-mil or 10-mil cross-laminated polyethylene sheeting sealed at all seams and penetrations, installed over drainage membranes to block moisture vapor transmission and control indoor humidity levels below the critical 60% threshold.
Our Process
Our technicians inspect your basement to identify the source and severity of water intrusion.
We design a tailored interior waterproofing solution based on your basement's specific needs.
Our certified crew installs drainage systems, sealants, and barriers with minimal disruption.
We test everything, clean up, and walk you through the completed work with warranty documentation.
Transparent Pricing
Honest pricing with no hidden fees. Every quote is customized to your specific needs.
| Service | Price Range |
|---|---|
| Drainage system installation | $4,000 – $10,000 |
| Sealant application | $3,000 – $8,000 |
| Vapor barrier installation | $2,500 – $6,000 |
Prices vary by project scope. Get an accurate quote with a free inspection.
Get Your Free QuoteClient 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
Protects your foundation from the outside by stopping water at the source before it reaches your basement.
Learn More →Professional sump pump installation and replacement to keep your basement flood-free year-round.
Learn More →New weeping tile installation and replacement to restore proper drainage around your foundation.
Learn More →Service Areas
We provide interior waterproofing throughout Toronto and the Greater Toronto Area.
Common Questions
