Overview: Retaining Wall Contractors
A retaining wall holds back soil that wants to slide, and in most of Canada it also has to survive the ground freezing behind it. Water trapped in the backfill turns to ice, swells and shoves the wall outward. Repeat that every winter and a wall that looked fine in August starts to lean. What prevents it is all buried: a compacted gravel base, clean stone behind the blocks, and a drain pipe that carries water away.
The rules depend on where the wall stands. Ontario's Building Code treats a wall taller than roughly waist height as a designated structure when it's next to public land, a building entrance or ground the public walks on. Those walls need a permit, and cities such as Barrie want an engineer's design. Calgary asks for a building permit once a wall holds back enough soil, and it adds up the heights of terraced walls built close together.
Digging comes first. In Ontario you're required to request utility locates through Ontario One Call before anyone breaks ground, and the service is free. On a ravine, shoreline or floodplain lot, the grading and fill for a wall can also need a permit from the local conservation authority.
Our listings show what each company states on its own website, with lines from public reviews. Start with your province, then open your city page to find crews that build walls where you live.
What retaining walls cost in Canada
Price the wall together with excavation, foundation and drainage. Wall height and retained loads matter as much as its visible material.
| Service | Estimated budget | What it covers |
|---|---|---|
| Site assessment and design | Quote requiredper defined design scope | State wall dimensions, soil information, required drawings and review visits.A simple site visit and an engineered design are different purchases. Obtain an itemized allowance for survey, drawings, engineering and review visits.What this estimate coversIncludes in this budget: Agreed assessment and design Budget separately or confirm: Geotechnical investigation; Permit fees |
| Segmental block retaining wall | C$35–C$125per sq ft of exposed wall face | Residential segmental block wall with standard access; area means exposed length × height.What this estimate coversIncludes in this budget: Block, routine excavation, compacted base and standard drainage backfill Budget separately or confirm: Engineering, permits and surveys; Major soil remediation, surcharge loads and removal of an existing wall |
| Timber retaining wall | C$35–C$60per sq ft of exposed wall face | Low timber garden retaining wall with ordinary access; confirm retained height and timber specification.What this estimate coversIncludes in this budget: Timber installation, routine base and drainage allowance Budget separately or confirm: Engineering, demolition, poor-soil remediation and major retained loads |
| Engineered structural retaining wall | Quote requiredper designed project | Wall supporting significant height, slopes or additional loads.Retained height, soil, drainage and nearby loads determine the engineered structure. A garden-wall unit rate is not a safe total for this project.What this estimate coversIncludes in this budget: Construction to the stated design Budget separately or confirm: Unlisted ground remediation; Unlisted approvals |
What changes the price
- height, slope and loads from buildings or vehicles above
- soil, groundwater, reinforcement and drainage requirements
- access, excavation, disposal and nearby property boundaries
Ask before accepting a quote
- What design, excavation, drainage and backfill are included in the quoted wall?
- Who confirms whether engineering or permits are required and pays those fees?
- What is the price basis if hidden soil or existing-wall conditions differ?
Use the correct area
- identify whether the rate uses exposed face area, total face area or length at a fixed height
- keep engineering and permit costs visible even when supplied by another professional
Canadian context
Permit and design requirements are local; a height threshold from another municipality should not be used for your project.
Budget estimates in Canadian dollars. Confirm applicable taxes and the final total in your quote. Rows may be alternatives or parts of the same job. Add only extras that are not already included in your quote.
Frequently asked questions
What goes in behind a properly built wall?
Clean crushed stone, never the clay that came out of the hole. Stone drains, and it gives freezing water room to expand without pushing on the blocks. A perforated pipe runs along the bottom of that stone to an outlet, and filter fabric keeps silt from clogging it. The fill goes in thin layers, each one compacted. Skip any of it and the first hard winter will show you where.
When does a wall need an engineer?
In Ontario, the Building Code steps in once it's taller than roughly waist height and stands beside public land, a building entrance or ground the public uses. Barrie counts a front yard that couriers and mail carriers cross. The city wants those walls designed by an engineer licensed in Ontario, with a guard along the top where people can reach it. Anywhere in Canada, a wall holding up a driveway or a slope deserves an engineer, whatever the bylaw says.
Do I need utility locates before the digging starts?
Yes, and in Ontario it's the law. You or your contractor must request locates through Ontario One Call before digging, and it costs nothing. Ask at least five business days ahead for a single property. Utilities mark their buried lines on the ground. Private lines, like a feed to a garage or a shed, are yours to find. British Columbia and Quebec run free locate services too.
Which material should the wall be built from?
Concrete block is the usual pick, because a wall of small units flexes with frost instead of cracking. Poured concrete fits tight spots and tall walls, and it needs footings below the frost line. Armour stone, the big quarried slabs, suits cottage slopes and rocky rural lots, though it takes a machine and an operator who knows how to seat each piece. Treated timber is cheapest and rots from the buried side first.
Why is my old wall leaning or bulging?
Water trapped behind it, nearly always, and every freeze gives it a harder shove. Look for courses that step out of line, joints opening in a staircase pattern, or soil leaking through the face. If it moves a little more each spring, the drainage behind it has failed. Patching the face won't reach the cause, so ask for a rebuild price alongside any repair quote.
