Foundation Repair in Greater Victoria

What each repair method costs, by published data

An average conceals the only thing that matters, because the jobs it blends differ by more than a factor of twenty. Priced method by method, the spread becomes legible, and a quote that lands far outside it is worth a second question.

The Canadian rows are Ontario figures and the American rows are national averages, so neither column is a Greater Victoria price and neither is a quote from us. What they agree on is the ratio. The distance between a crack you inject and a corner you underpin is not a percentage, it is an order of magnitude, which is why the diagnosis is worth more than the estimate.

Two line items go missing from the cheap end of that list, and both are structural rather than cosmetic: the engineering a soft-soil site forces, and the drainage that caused the problem in the first place. The next three sections are those.

The soil number that decides whether a repair needs an engineer

Whether foundation repair on a Victoria house is a routine job or an engineered one is settled by a number most homeowners never hear: the allowable bearing pressure of the ground under the footing. It is published, and it is not a judgement call.

Maximum allowable bearing pressure runs 500 kPa for sound rock, 200 kPa for till, 150 kPa for stiff clay or dense sand, 75 kPa for firm clay, and 40 kPa for soft clay (BC Building Code, Table 9.4.4.1).

That table has a cliff in it. The prescriptive route, Section 9.15, is the part of the Code that lets a footing and a foundation wall be sized from a table instead of by calculation, and it applies only on stable soils with an allowable bearing pressure of 75 kPa or greater (Section 9.15, Footings and Foundations). Soft clay at 40 kPa sits below that line. On that ground a foundation has to be designed under Section 9.4 instead, which means a designer, a calculation, and a line on the quote that a neighbouring house on firmer soil never sees.

Groundwater moves the same number again. Where a foundation bears on gravel, sand or silt and the water table sits within a distance below the bearing surface equal to the width of the foundation, the allowable bearing pressure drops to 50% of the table value (Article 9.4.4.3). On a wet lot with a high winter water table, that clause is what turns a straightforward underpinning into an engineered one, and it is the single most common reason two quotes on the same street are not comparable.

Why so many older block basements bow at the same height

A bowing basement wall is rarely a mystery. It is a wall holding back more soil than its thickness was ever rated to hold, and the rating is published.

Assembled from Table 9.15.4.2.A, which governs walls not exceeding 3.0 m in unsupported height (BC Building Code, Section 9.15), free-access text published by BC Publications.

Read the second row against the local housing stock. A 190 mm unreinforced block wall, the ordinary older basement in this region, is rated for 0.9 m of finished ground above the basement floor when nothing braces the top of the wall, and 1.2 m when the floor above braces it. A great many of those basements were later backfilled higher, or had a patio, a driveway or a raised planter built up against them. The wall did not fail. It was asked to hold back something the table never said it could, and the horizontal crack across its middle is the receipt.

This is also why bracing a wall without lowering the load, or without fixing the water that made the soil heavier, buys time rather than a repair.

The drainage the Code requires, and the failure that fills a basement

Most foundation repair in this region begins as a water problem. The Code is specific about what the drainage has to be. The bottom of every exterior foundation wall must be drained, drain pipe must be not less than 100 mm in diameter, and its top and sides must be covered with not less than 150 mm of crushed stone carrying no more than 10% of material that passes a 4 mm sieve (BC Building Code, Section 9.14, Drainage).

A sump pit, where one is used, must be not less than 750 mm deep and not less than 0.25 m2 in area, and it must have a cover. Foundation drains have to discharge to a sewer, a drainage ditch or a dry well, and a dry well has to sit at least five metres clear of the building foundation.

Perimeter drains around older Greater Victoria homes are often the original clay tile or unperforated pipe from the era the house was built, and they silt up. Once the drain stops carrying water away, the soil against the wall stays saturated through the winter, and saturated soil is heavier and pushes harder. That is the chain behind the two problems this region produces most: water in the basement, and a wall that has started to move. Repairing the wall without repairing the drain repairs the symptom.

The excavation rule that reprices an exterior repair

The cheap version of a foundation repair is done from inside. The durable version is often done from outside, and outside means an excavation against the wall, which is governed by the WorkSafeBC Occupational Health and Safety Regulation rather than by the Building Code.

Where a worker enters an excavation, the sides must be sloped as specified in writing by a qualified registered professional, cut back to a stable angle, or supported by an engineered system. The Regulation defines a trench as an excavation over 1.2 m deep and less than 3.7 m wide at the bottom (WorkSafeBC OHS Regulation, Part 20).

That is a real cost line rather than a formality. Trench safety is why an exterior repair on a tight urban lot, with a neighbouring house, a driveway or a mature tree inside the slope zone, can cost several times an interior repair of the same wall. It is also why a quote that proposes a deep vertical cut against a foundation with no shoring is the quote to set aside.

What to have ready before an inspection

The assessment moves faster, and the quote comes back tighter, when these are known before anyone arrives.

Severity and cause cannot be graded remotely. Book an on-site inspection.

• Where the cracking is, which way it runs, and whether it has moved. Direction is the first sorting question, and it is covered in foundation crack repair.
• Whether any wall is visibly curving, leaning, or shearing along a mortar joint. That is the table above showing up in the real world, and it is treated in bowing wall repair.
• Whether doors stick, floors slope, or one corner has dropped. That pattern is settlement rather than cracking, and it is handled in foundation settlement repair.
• Whether the basement or crawl space takes water, and when. Water after every heavy rain points at drainage before it points at the wall, which usually means exterior perimeter drains.
• How high the finished ground outside sits against the foundation wall, and whether a patio, driveway or planter was ever built up against it.
• Any soils or geotechnical report from the original build or a past sale, and a look at our guide to foundation repair cost in Victoria BC.