Retaining walls, steps and raised patios

A retaining wall holds back soil and may also need to manage water and loads nearby. Its dimensions, ground conditions and drainage belong in a site-specific design, alongside any required professional input and municipal approvals.

Discuss structural and ground conditions. Ask a qualified professional to assess the proposed dimensions, drainage, frost exposure and ground conditions. Confirm whether engineered drawings, guards or municipal approvals are needed; general web dimensions are not a design for your property.

Before excavation. Request utility locates and follow the current instructions from Ontario Dig Authority, including any private-locate arrangements needed for your property. Confirm the locate package with the person performing the excavation before work starts.

Step three: the base and the drainage behind the wall. Two things fail walls in this city, and both are behind them. Water pressure is the first: a retaining wall needs a drainage layer of clear stone against its back face and a perforated drain at the bottom taken to a daylight outlet, so water leaves rather than pushing. Frost is the second: saturated clay behind a wall expands when it freezes and pushes the wall outward, one winter at a time. Clear stone, geotextile between the stone and the clay, and a functioning drain are what prevent it, and they are exactly the items a low quote leaves out.

Step four: building the wall. Levelling course compacted and checked, blocks set with the specified setback, geogrid layers tied back into the retained soil at the intervals the design calls for, backfill in lifts and compacted in stages rather than all at once. Ask the qualified designer to specify any reinforcement needed for the wall system, soils and loads on this property.

Step five: caps, steps and guards. Caps adhered, steps built with consistent risers because inconsistent ones are the commonest trip hazard in a garden, and a guard where the code requires one. Steps in a public-facing location should follow the rise and run the Building Code sets rather than whatever the slope produced.

Discuss the schedule early. Ask about design revisions, approvals, material availability, access and weather-dependent work. Agree the sequence and any dependencies with the contractor before fixing dates.

What to include when comparing prices. Compare the wall dimensions, engineering if needed, excavation, base, drainage, reinforcement, caps, steps, guards and restoration. Ask who handles approvals and how unexpected ground conditions are priced. A site-specific written scope is the basis for comparing quotes.

Discuss structural and ground conditions. Ask a qualified professional to assess the proposed dimensions, drainage, frost exposure and ground conditions. Confirm whether engineered drawings, guards or municipal approvals are needed; general web dimensions are not a design for your property.

Ask about qualifications and responsibilities. Request relevant experience, insurance information and the written scope. Ask which professional design input or approvals your project needs; verify any claimed professional title through the relevant official directory, such as the PEO directory. This site does not verify a contractor’s credentials.