Drainage and Foundation Repair in Richmond: Living a Metre Above the Sea on Soft Ground

What delta ground does to a house

The silt under Richmond compresses under weight, so houses settle, and a house with a heavy addition on one side or a garage slab poured on fill settles unevenly. The signs are doors and windows that stick, cracks running diagonally from window corners, a slab that has dropped away from the wall, and steps that no longer meet the porch. Some settlement in the first years is expected; movement that keeps going, or that opens cracks wider than a coin, needs a geotechnical engineer’s opinion before anyone quotes piles.

The water table sits close to the surface year-round and rises in the winter rains. Crawlspaces flood or stay damp, slabs wick moisture, and the perimeter drains that new houses are built with silt up over the years. Older Steveston and Burkeville houses may have no perimeter drainage at all.

The dikes are the City’s; your lot is yours

The City of Richmond maintains the dikes, the pump stations and the network of ditches, culverts and storm sewers that keep the island drained. If a roadside ditch or culvert is blocked and flooding your frontage, call the City. Everything inside your property line is yours: the perimeter drains around the foundation, the sump if there is one, the crawlspace, and the grading of the lot. Many Richmond lots are flat and drain nowhere, so a drainage contractor may need to install a sump and pump water to the street or a ditch.

Richmond publishes flood-construction levels for new building and its dike master plan; those matter for renovations and additions, which may need to be built to a set elevation. Ask the City’s building department before planning an addition.

Fixing a wet crawlspace

A crawlspace on delta ground needs three things: perimeter drainage that works, a way to remove water that reaches the crawlspace, and a vapour barrier over the soil so ground moisture does not condense on the joists. A dehumidifier alone treats the symptom. A drainage contractor should inspect or camera the perimeter drains, flush or replace silted sections, install a sump and pump where the lot cannot drain by gravity, and lay a sealed polyethylene barrier over the earth. Ventilation and, in some houses, insulation of the crawlspace walls complete the job.

Mould in the joists and rot in the sill plate are the costs of leaving it. If the floor above feels spongy, get a contractor in before the winter rains.

• Photos of the crawlspace floor and joists
• Where water stands after rain, inside and out
• Age of the house and whether perimeter drains exist
• Crack widths and whether they are growing
• City drainage map for your street, if flooding starts at the road

Hiring a contractor and reading a quote

Drainage and foundation work is unlicensed in BC. Ask for a certificate of liability insurance and a WorkSafeBC clearance letter, and for foundation work, ask whether the design comes from an engineer. A drainage quote should state whether the drains were inspected by camera, which sections are being replaced, where the water will be discharged, and the warranty. A foundation quote for piling or underpinning should come with the geotechnical report it is based on. Consumer Protection BC publishes guidance on contractor contracts and deposits.

Excavation near a dike, a ditch or a City drainage easement needs the City’s approval. Ask the contractor who is applying.