Exterior basement waterproofing means digging a trench along the outside of the foundation wall, cleaning the wall, and repairing cracks. The crew then applies a waterproof membrane and a drainage board, lays new weeping tile at the footing, and backfills with clear stone and soil. The work stops water before it reaches the concrete. It takes days to weeks and disturbs the yard beside the house.
When exterior work makes sense
Exterior waterproofing treats the wall from the soil side. Water in a Toronto basement often comes from heavy clay soil that holds water against the wall. Spring melt and summer storms add to the load. Many older houses in Etobicoke and parts of Vaughan have clay-heavy ground and old drainage that has aged out.
Exterior work is a good fit when:
- the foundation wall itself is cracked, crumbling or has failed old parging
- the old weeping tile is clogged, crushed or missing
- the basement is unfinished and the problem is clearly at the wall
- the yard beside the house is open and a machine can reach it
It is a poor fit when a deck, a neighbour’s fence, a garage, a driveway or a mature tree blocks the dig. In those cases an interior system or a partial dig may be the only option. Ask each company to explain why it recommends one method over the other.
The process step by step
Every contractor sequences the job a little differently. The core steps are the same.
1. Site check, utility locates and planning
Before anyone digs, the contractor checks where the work will go. Utility locates are needed for gas, hydro, water and communications lines. In Ontario, the locate request goes through Ontario One Call. The contractor also plans where the soil will sit, how the machine will reach the wall, and what must be moved first.
Ask whether a permit is needed. The answer depends on your city and the scope. Check with your municipal building department before work starts.
2. Excavation
A small excavator or crews with hand tools dig a trench to the bottom of the footing. The trench is wide enough for workers to stand in and apply materials. Deep trenches next to a house need shoring or sloped sides for worker safety. This is a safety rule, not an optional extra.
Soil is piled on tarps or hauled away. Where space is tight, as on many Toronto lots, crews sometimes dig in short sections and backfill each one, which makes the job slower.
3. Cleaning and inspection
Once the wall is exposed, the crew removes old tar, parging and dirt. They then inspect the concrete or block. This is when you see the real condition of the foundation. Ask the contractor to show you photos of cracks, honeycombing, failed joints and the old drainage before they cover them.
4. Crack and wall repair
Cracks get repaired before the membrane goes on. Methods vary by the type of crack and by whether the wall moves. A hairline shrinkage crack and a crack from settlement are different problems. If you suspect movement, consider a structural opinion before you pay for waterproofing alone.
Block walls often get a parge coat to make a smooth surface. The surface must be dry and sound for the membrane to bond.
5. Waterproof membrane
The membrane is the main barrier. Common products include a spray or trowel-applied rubberized asphalt or polymer-modified coating, and self-adhesive sheet membranes. Each has its own cure time, thickness and temperature limits. Read the manufacturer’s technical data sheet for the product named in your quote. The data sheet states what the product is rated for and how it must be applied.
Ask for the product name, the coating thickness, and whether the membrane runs from the footing up past grade. A membrane that stops short leaves a path for water.
6. Drainage board
A dimpled plastic drainage board goes over the membrane. It protects the coating from stone and soil during backfill. It also creates a gap so water can flow down the wall to the drain instead of pressing against the membrane. Fabric on the outside keeps fine soil out of the gap, which matters in clay.
7. Weeping tile at the footing
The weeping tile is a perforated pipe, usually wrapped in filter fabric, that sits beside the footing and collects groundwater. It is bedded in clear stone. Water from the pipe must go somewhere: to a sump pit and pump, or to a drain connection where the local rules allow it.
That last point matters in Toronto. The City of Toronto has a basement flooding protection subsidy programme that covers certain flood-protection work, such as backwater valves, sump pumps, and disconnecting the weeping tile from the storm sewer. Eligibility, amounts and permit rules change. Read the city page before you sign a contract, and do not rely on a contractor’s summary.
8. Backfill and compaction
The crew fills the trench with clear stone near the pipe and the wall, then soil above. Good backfill is placed in layers and compacted. Poor compaction leads to settling, which can leave a dip next to the house where water collects. Finished grade should slope away from the foundation.
9. Surface restoration
The last step is the surface. This can mean topsoil and sod, or new walkways, patios and planting beds. Some quotes include restoration and some do not. Confirm this in writing.
Typical timeline
Timelines vary by wall length, footing depth, soil, access, weather and the number of cracks to fix. The table shows the usual order of work and what changes the time. We do not publish a day count here, because no single figure fits every house. Ask each contractor for a written schedule.
| Stage | What happens | What slows it down |
|---|---|---|
| Planning and locates | Utility marking, permit check, material order | Permit queues, locate delays |
| Excavation | Trench to footing depth | Depth, tight access, rock or boulders, water in the trench |
| Cleaning and repair | Wall prep, crack repair | Extra cracks, failed block or masonry |
| Membrane and board | Coating, cure time, drainage board | Cold or wet weather, cure time |
| Weeping tile | Pipe, stone, connection to sump or outlet | Discharge route, sump pit work inside |
| Backfill | Layered fill and compaction | Hauling soil, tight space |
| Restoration | Grading, sod, hardscape | Season, who is responsible |
Rain can pause an open trench. A trench that stays open for days is a risk for the house and for anyone near it, so ask what the plan is for storms.
Landscaping and property impact
Plan for the yard to look worse before it looks better. Expect the following:
- Plants, shrubs and small trees in the dig zone are removed or lifted.
- Patios, walkways, steps and decks next to the wall may need to come out and go back in.
- Roots near the foundation may be cut, so ask an arborist about large trees.
- Fill will settle for a season or more, and the grade may need a top-up.
- Neighbours may need notice, especially on narrow lots where the machine works close to the fence line.
Many Toronto, Etobicoke and Vaughan lots are narrow, and side yards can be a metre or less. A dig in a narrow side yard is slow and may call for hand work. This changes both time and cost.
What does it cost?
Prices vary a lot, and we have no cost basis we can verify, so we do not print a dollar figure. Exterior work costs more than most interior systems because of excavation, haulage and restoration. The main drivers are:
- the length and depth of the wall that needs digging
- access for a machine, and the amount of hand digging
- the condition of the wall and the number of repairs
- hardscape and landscape removal and restoration
- the discharge route for the new drain
Ask for itemised written quotes from several companies, and check that each quote covers the same scope. A quote that leaves out restoration or compaction is not comparable with one that includes them.
What our boards show for Toronto, Etobicoke and Vaughan
Our boards rank companies by Google rating and review count. They are data, not endorsements. They do not tell you which company suits your house. Data month: 2026-09.
| Board | Companies ranked | Median rating | Median reviews | Total reviews | Under 20 reviews |
|---|---|---|---|---|---|
| Basement waterproofing companies in Toronto | 20 | 5.0 | 100 | 3,989 | 0 |
| Basement waterproofing companies in Etobicoke | 20 | 4.95 | 91.5 | 3,242 | 3 |
| Basement waterproofing companies in Vaughan | 20 | 4.95 | 77.5 | 3,463 | 4 |
What this means for choosing:
- Median ratings are near the top of the scale in all three towns, so rating alone does not separate companies. Review count and the details inside reviews help more.
- The Toronto board has no company under 20 reviews. In Etobicoke, 3 of 20 have fewer than 20 reviews, and in Vaughan, 4 of 20 do. A rating from a small sample moves easily.
- Many of the top-ranked companies serve more than one of these towns, so the same names appear on several boards. Check the profile for the service area and the services listed.
- A Google rating does not measure excavation quality. Ask any company about membrane product, drainage board, backfill method and restoration.
If your problem may be structural, also see the foundation repair companies in Toronto board. For other towns, the basement waterproofing hub lists every board.
Questions to ask before you sign
- Which membrane product will you use, and can I see the data sheet?
- Do you dig the full perimeter or only the problem walls?
- Where does the new weeping tile discharge, and is a permit needed?
- Who restores the grass, patio or walkway, and is it in the quote?
- What does the written warranty cover, and is it transferable to a buyer?
- How do you protect the open trench during rain?
- Who holds the permit and the insurance certificates?
Get the answers in writing. A clear written scope is the best way to compare quotes.
Frequently asked questions
How long does exterior basement waterproofing take?
Duration depends on the length of wall, the depth of the footing, the soil and the weather. A small house with easy access can take days, and a deep or complex job can take longer. Ask each contractor for a written schedule that includes backfill and cleanup.
Will exterior waterproofing ruin my yard?
The work removes a trench of soil along the foundation, so plants, patios, walkways and decks in that strip are disturbed or removed. Soil goes back after the work, but it settles over time. Ask who restores the landscaping and in what form.
Is exterior waterproofing better than interior waterproofing?
Exterior work treats the wall where the water arrives and can repair the foundation face. Interior systems manage water that has already entered and cause less disturbance outside. The right choice depends on access, the cause of the leak and the budget.
Do I need a permit for exterior waterproofing?
It depends on the municipality and the scope. Work near property lines, public utilities or a sewer connection can need approval. Call your city building department before you sign, and ask the contractor who pulls any permit.