Retaining wall cost breakdown
Poured Concrete Retaining Wall Cost Calculator
Answer first: poured concrete retaining walls cost $20–$50 per linear foot for walls up to 4 ft tall in 2026. A 20 ft × 4 ft wall runs $400–$1,000 in materials and $1,600–$4,000 installed. Walls over 4 ft need an engineer.
20 ft × 2 ft wall (small landscape wall)
$400–$1,000 installed at $20–$50/lin ft
No engineer required for walls under 3 ft in most jurisdictions. 6-in thick wall, 12-in footing. Gravel backfill and drain pipe add $5–$10/lin ft.
20 ft × 4 ft wall (typical retaining wall)
$800–$2,000 installed — REQUIRES engineer review
Walls 4 ft and taller require engineering design and permits in most areas. 8-in thick wall, 16-in footing below frost line. #5 rebar horizontal and vertical.
20 ft × 6 ft wall (steep slope)
$2,400–$5,600 installed — engineer + permit required
High-load walls need 10-in+ thickness, deeper footings, and engineered drainage. Expect $40–$80/lin ft for walls 6+ ft tall. Failure of an engineered wall can be catastrophic.
Poured concrete vs segmental block wall
Poured: $20–$50/lin ft | Block: $10–$20/lin ft (materials only)
Poured concrete is monolithic and watertight. Segmental block is modular and DIY-friendly for walls under 4 ft. For walls over 4 ft, poured concrete is typically stronger and more cost-effective.
Interactive workflow
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How much does a poured concrete retaining wall cost?
Poured concrete retaining walls cost $20–$50 per linear foot installed for walls up to 4 ft tall in 2026. A 20 ft wall runs $400–$1,000. A 40 ft wall runs $800–$2,000. For walls 4–8 ft tall, add engineered design ($1,000–$3,000) and expect higher per-foot costs ($40–$80/lin ft) for the additional concrete volume, reinforcement, and footing depth required.
How much concrete do I need for a retaining wall?
Multiply wall length × height × thickness (in feet) ÷ 27 for cubic yards. An 8-in thick × 4-ft tall × 20-ft long wall: 20 × 4 × 0.667 ÷ 27 = 1.98 yd³ before waste. With 10% waste: 2.18 yd³. The footing (usually twice the wall width wide and as deep as the wall is thick) adds significant concrete. Consult an engineer for exact footing dimensions based on soil conditions.
Do I need an engineer for a concrete retaining wall?
Most codes require a licensed engineer for retaining walls over 3–4 ft tall, walls that retain near structures, walls on slopes, or walls near public property. Even for shorter walls on private property, an engineering review ($500–$2,000) is worthwhile — it prevents costly failures that can damage your property. Many municipalities also require a permit for any retaining wall over 24–36 in tall.
How thick should a poured concrete retaining wall be?
As a rule of thumb, the wall base should be as thick as the wall is tall. An 8-in wall works for walls up to about 4 ft. A 12-in wall for walls up to 6 ft. For taller walls, the base thickness must be engineered based on soil pressure, surcharge load (parking, structures), and local seismic requirements. The footing is typically 2× the wall thickness wide and placed below the frost line.
What is the difference between a poured concrete wall and a block retaining wall?
Poured concrete is monolithic (one continuous structure) — stronger, watertight, and no joints for water infiltration. Concrete block (CMU) walls are modular — easier to DIY and repair, but joints can allow water seepage. Segmental retaining wall blocks (like Allan Block) are gravity walls with no mortar — good for low walls under 4 ft on gentle slopes. Poured concrete costs more but is preferred for walls over 4 ft or in high-load applications.
Planning disclaimer
This calculator provides planning estimates. Walls 4 ft and taller require engineering design and permits in most jurisdictions. Confirm all requirements with a licensed engineer before construction.