Enter the wall's length and exposed height to see its face area, a typical 2026 GTA range, and whether it likely needs a permit and engineer.
Typical GTA range from the published 2026 guides listed under Sources, not a quote. 1 m is about 3.3 ft. Permit rules from the Ontario Building Code; ravine and creek lots may need conservation-authority approval even for smaller walls.
Retaining wall cost examples (block vs armour stone)
| Wall | Block | Armour stone |
|---|---|---|
| 30 ft long × 2 ft high (60 sq ft of face) | $2,500–$4,500 | $3,500–$6,500 |
| 30 ft long × 3 ft high (90 sq ft of face) | $4,000–$7,000 | $5,500–$10,000 |
| 30 ft long × 4 ft high (120 sq ft of face) | $5,500–$9,000 | $7,000–$13,000 |
Before HST, rounded to the nearest $500, from published 2026 GTA guides (block $45–$75 and armour stone $60–$110 per sq ft of face). Tall structural walls run about $85–$120+ per sq ft, and engineering for taller walls typically adds $1,500–$4,000.
Retaining wall cost per square foot and per linear foot
Contractors in Ontario usually price walls per square foot of face, but many homeowners think per linear foot. To convert, multiply the per-square-foot price by the wall's exposed height:
| Exposed height | Block (per linear ft) | Armour stone (per linear ft) |
|---|---|---|
| 2 ft | $90–$150 | $120–$220 |
| 3 ft | $135–$225 | $180–$330 |
| 4 ft | $180–$300 | $240–$440 |
Armour stone is also sold by the ton at the quarry, but the installed price depends mostly on stone size, machine access and wall height, so per square foot of face is the fairer way to compare quotes.
How the retaining wall cost estimator works
Retaining walls are priced by wall face: length × exposed height. The calculator multiplies your face area by the typical installed range for the wall type you choose and rounds to the nearest $500. It then checks the height against the Ontario Building Code's 1 m rule and tells you whether a permit and engineer are likely. The full breakdown is in our retaining wall cost guide.
What height retaining wall needs a permit in Ontario?
Under the Ontario Building Code, a wall more than 1 m (3.3 ft) of exposed height is a designated structure when it's next to public property, an access to a building, or private property the public is admitted to. Those walls need a building permit and a professional engineer's design. Lots near ravines and creeks may also need approval from Credit Valley Conservation, TRCA or Toronto's ravine by-law, even for smaller walls.
How to measure your wall
- Length: the full run of the wall, including returns at the ends.
- Exposed height: from the finished ground in front of the wall to the top of the cap. The buried first course isn't counted.
- Several terraces? Run each wall separately and add them up.
Questions about this tool
How much does a retaining wall cost in Ontario?
Most residential walls in the GTA cost $45–$110 per square foot of wall face installed in 2026: block at the lower end, armour stone and tall walls at the upper end. A 30 ft long, 3 ft high block wall is roughly $4,000–$7,000 before HST.
How much does a retaining wall cost per linear foot?
Multiply the per-square-foot price by the exposed height. A 3 ft block wall works out to about $135–$225 per linear foot, and a 3 ft armour stone wall about $180–$330.
How much does a retaining wall cost per square foot in the GTA?
Typically $45–$75 per sq ft of wall face for segmental block, $60–$110 for armour stone, and $85–$120+ for tall structural walls, before HST.
Do I need a permit for a 4 ft retaining wall?
Possibly. 4 ft is over 1 m, so under the Ontario Building Code it needs a permit and an engineer's design if it's next to public property, an access to a building, or private property the public is admitted to. Lots near ravines or creeks may also need conservation-authority approval.
What is the maximum retaining wall height without a permit in Ontario?
1 m (about 3.3 ft) of exposed height, for walls next to public property, a building access or property the public uses. Conservation-regulated lots can need approval for lower walls too.
Do I need a permit for a 3 ft retaining wall?
Usually not. A wall under 1 m (3.3 ft) of exposed height isn't a designated structure under the Ontario Building Code, unless the lot is regulated by a conservation authority or ravine by-law.
Why are retaining walls priced by the square foot of face?
Because both materials and labour scale with how much wall is showing. A long low wall and a short tall wall with the same face area cost about the same, unless the tall one needs engineering.
How do I get an exact price?
Text photos and rough measurements to 437-299-1681, or book a free site visit. We check soil, drainage and access and send a written quote.