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Structures · RetainingICF Retaining Walls:
ICF Retaining Walls:
When Concrete Beats Block for Holding Back a Hill
Most landscape retaining walls are stacked block, and for a garden step that is fine. When the wall holds up a driveway, a house, or more than about a metre of soil, it becomes a structure. Reinforced concrete poured in ICF is one of the cleanest ways to build one.
The Short Answer
An ICF retaining wall is a reinforced concrete wall on a proper footing, formed with insulated concrete forms. It suits tall walls, walls that carry loads like driveways or buildings, and walls that are part of a house or garage. In 2026 they typically run $48 to $62 per square foot of wall in Ontario, plus excavation and drainage. Walls over about 1 metre, or any wall supporting a structure or a driveway, generally need an engineer and often a permit.
When ICF Makes Sense
Part of a building
Walkout side walls, garage walls into a hill, a lower-level room cut into a slope.
Tall walls
Anything over about a metre, where segmental blocks need geogrid reaching far back into the hill.
Tight spaces
Where there is no room to excavate the long geogrid zone a block wall needs.
Loads on top
Driveways, parking, a building or a pool near the top of the wall.
The foam on the face can be finished with stone, parging or a manufactured facing so it does not look like a basement wall in the garden.
What Makes a Retaining Wall Work
- The footing. Sized and reinforced to stop the wall sliding and tipping, with a heel under the retained soil in most designs.
- The steel. Heavy vertical bars on the soil side, tied into the footing.
- Drainage. Free-draining stone behind the wall and a perforated pipe at the base. Water pressure behind a wall is what tips most of them over.
- Frost. Footing below frost depth, typically about 1.2 metres in much of southern Ontario.
- Waterproofing. A membrane on the soil side if the wall is part of a heated space.
Get a Real Number for Your Project
Send us your plans or a rough sketch. We price the ICF work from real wall areas, not guesses, and tell you straight if ICF is not the right fit.
What It Costs
| Item | Typical 2026 range |
|---|---|
| ICF retaining wall, engineered with drainage | $48–$62 / sq ft of wall |
| Excavation and backfill | Site dependent, often $5,000–$20,000 |
| Engineering | $1,500–$4,000 |
| Facing (stone veneer, parge) | $10–$45 / sq ft |
For comparison, a segmental block wall is often cheaper per square foot of face for short garden walls, but the gap closes or reverses on tall walls once you count geogrid, excavation and engineering.
Engineering and Permits
Retaining walls that support a building, a driveway or a significant height of soil generally need a design by a Professional Engineer, and many municipalities require a building permit for retaining walls over about 1 metre in exposed height, especially near property lines or public ways. Conservation authority approval may be needed on regulated lots. See when you need an engineer for ICF.
Get a Real Number for Your Project
Send us your plans or a rough sketch. We price the ICF work from real wall areas, not guesses, and tell you straight if ICF is not the right fit.
Free 30-second estimate
What Will My ICF Walls Cost?
Punch in rough sizes. You get a real 2026 Ontario range for installed ICF walls, plus what conventional walls would cost for the same job. No phone call, no sales pitch.
Your estimate
Fill in the boxes and hit Show My Estimate. Rough numbers are fine. A tape measure off the drawings is plenty.
Installed ICF walls
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- Wall area-
- Conventional walls, same job-
- Real ICF premium-
Turn this into a full line-by-line budget: the ICF Build Budget Guide ($29.99) →
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Questions We Get
Can you build a retaining wall with ICF?+
Yes. ICF forms a reinforced concrete retaining wall on a proper footing. It suits tall walls, walls carrying loads and walls that are part of a building.
How much does an ICF retaining wall cost?+
About $48 to $62 per square foot of wall in Ontario in 2026, plus excavation, engineering and any decorative facing.
Does a retaining wall need a permit in Ontario?+
Many municipalities require a permit for retaining walls over about 1 metre of exposed height, particularly near lot lines or public property. Check with your building department.
Is ICF better than block for a retaining wall?+
For short garden walls, segmental block is usually cheaper. For tall walls, walls with loads on top, and tight sites, reinforced concrete in ICF is often the better and sometimes the cheaper choice.