How much does a retaining wall cost?
A retaining wall typically costs $20–$60 per square foot of wall face installed. A common 30 ft long, 4 ft high wall (120 sq ft) runs about $3,000–$9,000, depending on material and engineering.
Ranges are typical planning guides — actual price varies by region, access, materials and your local pro. Always get a written quote.
| Material | Typical cost | Notes |
|---|---|---|
| Pressure-treated timber | $20–$30 / sq ft | Cheapest; 15–20 yr life |
| Segmental concrete block (SRW) | $25–$45 / sq ft | Most popular choice |
| Natural stone | $40–$60+ / sq ft | Premium look, skilled labour |
| Poured concrete | $30–$55 / sq ft | Formwork + rebar |
| Engineering & permits (walls 4 ft+) | +$500–$2,000 | Required in most areas |
What affects the price
Height
Cost rises faster than height. Walls over 4 ft usually need an engineer, permits and geogrid reinforcement tied back into the slope — often doubling the per-foot price.
Drainage
Water pressure is what destroys retaining walls. Gravel backfill, drainage fabric and a perforated pipe behind the wall are non-negotiable and part of any honest quote.
Material and access
Timber is cheapest but shortest-lived; segmental block is the value pick; natural stone costs the most in labour. Tight access that stops machine excavation adds hand-digging hours.
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How much does a retaining wall cost?
Typically $20–$60 per square foot of wall face — about $3,000–$9,000 for a 30 ft long, 4 ft high wall. Material, height and engineering set the price.
Do I need a permit for a retaining wall?
In most US jurisdictions, walls over 4 ft high (measured from the footing) need a permit and engineered drawings. Some areas trigger at 3 ft, so check locally before building.
What is the cheapest retaining wall material?
Pressure-treated timber at $20–$30/sq ft, but it lasts 15–20 years. Segmental concrete block costs a little more and lasts 50+, so it usually wins on lifetime value.