Exterior Basement Waterproofing
Stop water at the source. Our exterior waterproofing system seals your foundation from the outside with a heavy-duty membrane, new weeping tile, and proper drainage — the same method specified by structural engineers and built to last 50+ years.
Attack the water problem at its origin
Exterior basement waterproofing involves excavating the soil around your foundation down to the footing — exposing the full exterior face of the foundation wall. The existing waterproofing membrane (if any) is removed, the wall is cleaned and repaired, active cracks are sealed, and a new rubberized waterproof membrane is applied to the full wall surface. A drainage board is installed to channel any residual moisture downward to new weeping tile at the footing, which connects to a discharge system or storm drain.
This is the only waterproofing method that stops water before it contacts your foundation wall. For homes with active structural cracks, crumbling parging, previous exterior waterproofing failures, or severe inward wall pressure, exterior is the correct solution. It also makes sense when the home is being prepared for sale and buyers want documentary proof of permanent foundation protection.
Exterior waterproofing costs more and takes longer than interior methods — typically 3–7 days and $20,000–$40,000 for a full perimeter treatment. But when the situation calls for it, it is the definitive, 50-year solution. We'll tell you honestly whether your home needs it — exterior isn't the right answer for every wet basement.
Ontario-Specific Note
Toronto and GTA homes built on clay-rich soil experience particularly high hydrostatic pressure during spring thaw and heavy rain events. Interior waterproofing is designed specifically to handle this pressure relief — it's the most common and most effective solution for our local soil conditions.
$120-$400+ per Linear Foot
Most full-perimeter homes: $20,000–$40,000
Most full-perimeter homes: $20,000–$40,000
| Scope | Typical Cost |
|---|---|
| One wall (crack repair) | $3,500–$8,000 |
| Two walls | $10,000–$20,000 |
| Full perimeter | $20,000–$50,000 |
| Corner repair | $2,000–$5,000 |
What's Included in Our Exterior System
How Exterior Waterproofing Works
Comprehensive Site Assessment
Our experts evaluate your foundation, soil conditions, drainage patterns, and landscaping. We identify all water entry points and develop a custom waterproofing plan.
Comprehensive Site Assessment
Before digging, Canada Waterproofers calls Ontario One Call to have underground utilities marked, helping us excavate safely and avoid damaging vital services like gas, hydro, water, sewer, and telecom.
Foundation Excavation
We carefully excavate around your foundation down to the footing level. Landscaping, walkways, and structures are removed and cataloged for restoration if agreed upon.
Foundation Repair & Preparation
Foundation walls are cleaned and inspected. Any cracks are repaired with hydraulic cement. The surface is prepared for membrane application.
Waterproof Membrane & Drainage
A heavy-duty waterproof membrane is applied to the foundation walls. New weeping tile is installed at the footing, connected to a sump system or storm drain.
Backfill & Site Restoration
Foundation is backfilled with gravel and soil in layers. Proper grading is established, landscaping is restored, and final inspection is completed.
When to Choose Exterior Over Interior
⚠ Requires Exterior
Active foundation cracks with water intrusion above the floor
Horizontal cracks or cracks above the floor-wall joint can't be resolved by interior drainage alone — the wall face needs to be sealed from the outside.
⚠ Requires Exterior
Bowing, cracking, or inward wall movement
Signs of hydrostatic pressure causing structural movement. Exterior work is required to relieve lateral pressure on the wall and restore structural integrity.
⚠ Requires Exterior
Failed or deteriorated existing exterior membrane
Older homes with failed rubber or asphalt-based exterior membranes need the old material removed and a modern rubberized membrane installed over the clean wall.
⚠ Requires Exterior
Interior waterproofing not keeping up with water volume
If an existing interior system is overwhelmed despite properly sized sump pumps, the volume of inflow suggests the exterior membrane has failed and needs replacement.
✓ Best Choice
Pre-sale — buyer-requested permanent protection
Buyers and home inspectors increasingly request exterior waterproofing documentation at resale. An exterior-treated foundation eliminates one of the most common buyer objections in GTA real estate.
✓ Best Choice
Major renovation requiring complete foundation access
If you're excavating for a new addition, underpinning, or landscaping overhaul, adding exterior waterproofing at the same time reduces overall cost significantly.
Canada Waterproofers is here to help
No job is too big or too small. Get in touch with us!
Serving GTA, Kitchener-Waterloo, Hamilton & Niagara
Toronto
Etobicoke, North York, Scarborough, East York, Downtown, Beaches and all city neighborhoods
Mississauga
Port Credit, Streetsville, Erin Mills, Meadowvale, Cooksville & surrounding areas
Brampton
Bramalea, Heart Lake, Springdale, Sandringham, Credit Valley & surrounding areas.
Oakville
Glen Abbey, Bronte, Old Oakville, River Oaks, West Oak Trails & surrounding areas
Burlington
Alton, Millcroft, Brant Hills, Orchard, Palmer & surrounding areas
Hamilton
Ancaster, Dundas, Stoney Creek, Waterdown, Binbrook and surrounding areas
Milton
Coates, Harrison, Beaty, Clarke, Scott & Surrounding Halton Region areas|
St. Catharines
Lakeshore, North End, Port Weller, Port Dalhousie, Old Grenridge, Western Hill and surrounding areas
Coming soon
Exterior Waterproofing FAQ
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