Foundation Waterproofing in Richmond Hill

We are OCM Excavation & Construction. We dig, waterproof, and reseal foundations across Richmond Hill — from the clay-heavy lots west of Yonge to the older two-storeys in Bayview Hill, South Richvale, Mill Pond, and Oak Ridges. Most calls we get are wet basements: water at the cove joint, efflorescence on the block, a damp corner that never dries. The fix is almost always at the wall, not the floor. Call 416-317-3090 for a site walk and a written quote.

Why foundation waterproofing in Richmond Hill matters

Richmond Hill sits on a clay belt. Clay holds water against the foundation wall instead of draining it away, so hydrostatic pressure builds up against the concrete or block. Add 30 freeze-thaw cycles a winter and a typical 1960s–1970s Bayview Hill or South Richvale foundation — parged block, tar coating, clay drain tile — has nothing left to fight with after 50 years. The tar oxidizes, the drain tile silts up, and water finds the cold joint.

North of Elgin Mills the ground changes. The Oak Ridges Moraine is an aquifer recharge area, so groundwater on Jefferson and Oak Ridges lots can sit higher than people expect — especially in spring. Doncrest and Observatory homes from the 1970s–1980s show the same pattern: original asphalt damp-proofing has failed, and lot grading toward the house finishes the job. That is what we are usually replacing when a Richmond Hill homeowner calls us about a leak.

Types of waterproofing we do

Exterior excavation waterproofing. This is the gold standard and what we recommend whenever access allows. We dig the affected wall down to the footing — typically 7 to 9 feet on a Richmond Hill basement — pressure-wash the foundation, patch parge cracks, and apply a rubberized membrane or peel-and-stick sheet membrane. A dimple board goes over the membrane to give water a path down to the drain tile, then we replace the weeping tile in clean ¾-inch clear stone with filter cloth, and backfill in lifts.

Interior waterproofing. Where access is impossible — additions tight to the lot line, a wall under a finished garage, a neighbour’s deck — we go inside. We break the slab along the affected wall, install interior weeping tile to a new sump pit, vapour barrier the wall, and pour back. It manages water rather than stopping it, but it works.

Weeping tile replacement and drainage retrofits. A lot of older Richmond Hill homes still have clay weeping tile. We replace it with perforated 4-inch PVC, tie it to the sump or the storm connection where one exists, and bed it in stone so it does its job for the next 40 years.

Window wells and below-grade entries. Rusted-out steel wells fill with water and dump it straight at the foundation. We replace the well, tie its drain to the weeping tile, and waterproof the wall section around it. Same approach for rear walk-out stairs that leak at the threshold.

Our waterproofing process

Site walk and leak source. We figure out whether you are dealing with hydrostatic pressure, a surface-water/grading issue, a window well, or a plumbing leak. Wrong diagnosis means a useless dig.
Locates and protection. Ontario One Call locates before any excavator hits dirt. Gas, hydro, Bell, Rogers, water service all marked. Tree roots on lot-line maples get hand-dug around.
Excavation to footing. We open a working trench wide enough to stand in — usually 3 to 4 feet at the bottom — down to the top of the footing.
Wall prep and membrane. Power-wash, repair parge cracks, then apply a rubberized membrane or self-adhered sheet. Dimple board over top, mechanically fastened at the top edge.
New weeping tile and stone. 4-inch perforated PVC, wrapped or with filter cloth, laid in clear stone at the footing, tied to a sump pit or existing drain.
Backfill in lifts and restore. We compact in 12-inch lifts to limit settlement, grade away from the house at minimum 2% slope for the first 2 metres, and restore sod, interlock, or concrete to match.

What affects waterproofing cost in Richmond Hill

House age and foundation type. A 1970s block foundation in Mill Pond or Crosby takes more wall prep than a 2010 poured wall in Jefferson.
Excavation depth. Full-height basements are 7–9 feet to footing. Deeper means more soil out and more shoring.
Soil and disposal. Clay is heavy and tested as solid non-hazardous fill under O. Reg. 406/19 before it goes to a licensed receiving site. That cost rides on the truck count.
Access. A clear side yard wide enough for a mini-ex is cheap. A back wall reached through a neighbour’s driveway, with hand-dig only, is not.
Scope of perimeter. One wall costs a fraction of a full perimeter dig. We will tell you straight whether you can get away with the affected wall or need to go around.
Tree and landscape protection. Mature trees near the foundation, interlock driveways, sprinkler systems, and gas lines all add labour.
By-law and conservation. Richmond Hill Site Alteration By-law 47-25 governs grade and fill changes. Lots on the east-side ravine system fall under TRCA Ontario Regulation 41/24 and may need a permit before we move soil near the slope. We handle the paperwork.
Restoration. Replacing sod is one thing. Rebuilding 200 sq ft of stamped concrete patio is another. Whatever you had before, we put back.

For more detail on our general method across the region, see our foundation waterproofing across Toronto and the GTA page. For broader site work in the city, our Richmond Hill excavation contractor and Richmond Hill trenching services cover everything around the dig — drainage trenches, services, grading.

Frequently asked questions

Do I really need exterior waterproofing if I only have one wet wall?

Often no. If the leak is isolated to one section and the rest of the perimeter is dry, we dig only that wall. We have done plenty of partial digs in Bayview Hill and Doncrest where a single corner was the issue. We will not push a full perimeter excavation if the water is not telling us to.

How long does an exterior waterproofing job take in Richmond Hill?

A single-wall exterior waterproofing on an average lot usually runs 3 to 5 working days from dig to backfill. A full perimeter on a clay-belt lot can run 7 to 10 days, longer with restoration. Weather and access drive the schedule more than anything else.

Is interior waterproofing as good as exterior?

No, and we will tell you that on the site walk. Exterior keeps water out of the wall. Interior manages water that has already entered the wall and gets it to a sump. On a Richmond Hill clay lot with hydrostatic pressure, exterior is the right answer when we can reach the wall. Interior is what we use when we can’t.

Do I need a permit to waterproof my Richmond Hill foundation?

Waterproofing itself usually does not need a building permit. Grade changes, large soil import or export, and work on regulated TRCA land may trigger Richmond Hill Site Alteration By-law 47-25 or a conservation authority permit. We confirm before we mobilize and we handle the application where one is required.

Will you damage my driveway, deck, or landscaping?

We protect what we can and remove what we must to reach the wall. Interlock pavers come up and get re-laid. Sod gets stripped and replaced. Decks within reach of the dig are either braced or partially dismantled and rebuilt. Anything we touch is documented before we start so there are no arguments at the end.

Talk to OCM about your Richmond Hill foundation

If you are watching water come in at the cove joint, seeing efflorescence on a block wall, or your weeping tile is the original clay tile from 1972, get us out for a look. Call 416-317-3090 or request a quote at our contact page.

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