Basement Waterproofing in St. Catharines

Water in your basement doesn’t fix itself. It gets worse, and the repair gets bigger.

AquaResist finds where the water is coming from and fixes it properly: leaking walls, foundation cracks, failed drainage and sump pump problems. You get a written 25-year warranty on the work we recommend.

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25+ years in waterproofing

Fully licensed & insured

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emergency line

Our Basement Waterproofing Services

Every wet basement has a different cause. We start with the cause, then pick the repair.

Exterior Foundation Waterproofing

We dig down to the footing, repair the wall, apply a waterproof membrane and install new drainage. The water gets stopped outside, before it touches your foundation.
Best for: leaking walls, failed old membranes, damaged exterior drainage.
Learn more about waterproofing.

Interior Drainage & Weeping Tile

We install a drainage system inside your basement that collects groundwater and sends it to a sump pit. No excavation around the house, so your yard, deck and driveway stay as they are.
Best for: water at the floor-wall joint, homes where outside digging isn’t practical.
Learn more about drainage.

Foundation Crack Repair

A crack is an entry point for water. We check its size, location and whether it’s still moving, then repair it with the right method. Some cracks can be sealed from inside. Others need outside work.

Sump Pumps & Battery Backup

A sump pump moves water out of your basement. A battery backup keeps it running when the power goes out, which is exactly when storms cause the most flooding. We install, replace and upgrade both.
Planning to lower your basement floor? We also do underpinning.

Signs Your Basement Needs Waterproofing

Water on the floor after rain or during spring melt

Damp or dark patches on concrete walls

Musty smell, even when you can’t see water

White, chalky deposits on walls (efflorescence)

Cracks that are wet, growing or stain-streaked

Peeling paint or rotting baseboards

Water around window wells

Don’t wait for a flood. A damp wall today is often a structural repair next year. Moisture also feeds mould, and that affects the air your family breathes.

Why Basements Leak in St. Catharines

Several local conditions work against your foundation:

Heavy clay soil. Clay holds water and pushes it against your walls.

Freeze-thaw cycles. Water gets into small cracks, freezes, and opens them wider every winter.

Spring melt and heavy storms. Lots of water arrives at once, and the ground can’t take it.

Older homes. Many St. Catharines houses have decades-old foundations, with aged membranes and worn-out weeping tile.

You can’t change the soil or the weather. You can change how water moves around your house.

Interior or Exterior Waterproofing?

Neither is always better. It depends on where the water enters.

Exterior waterproofing fits when:	Interior drainage fits when:
water comes through the outside wall	water appears at the floor-wall joint
the old membrane or weeping tile has failed	digging outside isn’t practical (tight lot, deck, driveway)
you can access the foundation for digging	you need a faster, less disruptive job

Some homes need both, plus crack repair or a new sump pump. We check on site and tell you what your house actually needs, including what it doesn’t need.

How Much Does Basement Waterproofing Cost in St. Catharines?

A single crack repair and a full exterior excavation are very different jobs. The price depends on:

– Method: interior drainage or exterior excavation
– Length and depth of the foundation to be repaired
– Access: decks, landscaping, driveways, tight side yards
– Existing damage: old membrane, broken weeping tile, cracks
– Drainage work: sump pump, discharge, backwater valve

You get a written estimate after we see the problem, not a guess over the phone.

24/7 emergency line

How the Job Works

Step 1

Call or send photos. Tell us what you’re seeing.

Step 2

Free on-site assessment. We find the source of the water and explain your options.

Step 3

Written estimate. Scope, price and timeline, in writing.

Step 4

Clean, careful work. We protect your home, do the repair and clean up when we’re done.

Step 5

Walkthrough and warranty. We review the finished work with you and give you your warranty in writing.

Our 25-Year Warranty

If you go ahead with the repairs we recommend, we back the work with a full written 25-year warranty. We recommend what’s needed to solve the problem permanently, not the cheapest patch that fails in two winters.

Why Homeowners Choose AquaResist

● 25+ years of experience with leaks, drainage and foundations
● Straight answers. We explain the cause before we quote
● 24/7 emergency line. Flooding doesn’t wait for business hours
● Clean job sites. Our customers regularly mention how tidy the crew leaves the house
● Full range in one company: waterproofing, drainage, crack repair, underpinning, concrete work and plumbing

Areas We Serve Near St. Catharines

We work with homeowners in St. Catharines and across Niagara. See our Niagara basement waterproofing page for the wider region. Call us to confirm service for your address: (416) 880-1330

Basement Waterproofing FAQ

What causes a leaking basement?

Foundation cracks, a failed waterproofing membrane, clogged or broken weeping tile, poor grading, window well problems and high groundwater. We find the actual cause before recommending a fix.

Is interior or exterior waterproofing better?

It depends on the leak. Exterior stops water at the outside wall. Interior collects and removes water that gets in. We inspect first, then recommend.

Can you fix a foundation crack without digging?

Often yes, by injecting the crack from inside. If the crack is moving, wide or part of a bigger drainage problem, exterior work may be needed.

How long does waterproofing take?

A crack repair can take hours. A full interior or exterior system usually takes several days. We give you a timeline in the written estimate.

What does your warranty cover?

We provide a written 25-year warranty on the work we recommend and you approve. Ask us for the full terms and we’ll go through them with you.

Get Your Free Estimate

Wet basement? Don’t wait for the next storm.
Call us, or send a few photos and a short description. We’ll tell you what to do next.

24/7 EMERGENCY LINE