# Wood Retaining Wall Cost: Timber, Ties, and Cedar

> Wood retaining walls cost $10 to $25 per square foot installed. Treatment levels, post spacing, lifespan, and three worked budgets with drainage.

Canonical: https://retainingwalllab.com/wood-retaining-wall-cost/

Last updated: 2026-11-09

Wood retaining wall cost is the price of the posts, the horizontal lagging, the fasteners, and the labor to set them, and it runs $10 to $25 per square foot of wall face installed. Drainage adds $5 to $15 per square foot. A 30-foot wall at 4 feet high is 120 square feet, which puts a typical pressure-treated job near $3,360 once drainage is included.

## What the Price Covers

A timber wall is a post-and-panel structure. Vertical posts are embedded in the ground or anchored to a deadman behind the wall, and horizontal boards or timbers span between them to hold the soil. The cost splits into four parts:

**Posts.** Usually 4x4 or 6x6, set 2 to 4 feet deep depending on height and soil. Post spacing of 4 to 8 feet sets how many you need.

**Lagging.** 2x10 or 2x12 boards, or stacked 6x6 timbers. This is the visible face and the largest material line.

**Fasteners and anchors.** Galvanized or stainless lag screws, through-bolts, and deadman assemblies. Cheap hardware is the most common source of early failure.

**Labor.** Digging post holes, setting posts, cutting and fitting lagging, and compacting backfill.

## The Three Wood Options

| Option | Installed rate | Expected life | Notes |
|---|---|---|---|
| Pressure-treated pine | $10–$18 per sq ft | 15–20 years | Ground-contact rated, most common |
| Cedar or cypress | $16–$25 per sq ft | 20–25 years | Naturally rot-resistant, fewer chemicals |
| Railroad ties | $12–$20 per sq ft | 10–20 years | Creosote restrictions apply in many areas |

Hardwoods such as ipe or black locust sit at or above the top of the range, and they are usually specified for a specific look rather than for budget. Whatever the species, the rating that matters is ground contact: lumber rated for above-ground use will rot at the soil line within a decade.

## Cost by Height

Height changes the rate in two ways. Taller walls need deeper posts and thicker lagging, and they carry more soil pressure, so the safety margin comes from material rather than from labor.

| Wall height | Posts | Installed rate | Cost per linear foot |
|---|---|---|---|
| 2 ft | 4x4 at 6 ft spacing | $10–$15 per sq ft | $20–$30 |
| 3 ft | 4x4 at 6 ft spacing | $12–$18 per sq ft | $36–$54 |
| 4 ft | 6x6 at 6 ft spacing | $15–$25 per sq ft | $60–$100 |
| 5 ft and above | 6x6, engineered | Above the standard range | Design required |

The per-linear-foot column is simply the per-square-foot rate multiplied by the height. At 4 feet and $18 per square foot, 4 × $18 = $72 per linear foot.

## Three Worked Budgets

**Garden wall, 40 square feet. 2 feet high by 20 feet long.**

Timber at $14: 40 × $14 = $560. Drainage at $8: 40 × $8 = $320. Total: $880.

**Typical residential wall, 120 square feet. 4 feet high by 30 feet long.**

Timber at $18: 120 × $18 = $2,160. Drainage at $10: 120 × $10 = $1,200. Total: $3,360.

**Taller wall, 180 square feet. 6 feet high by 30 feet long.**

This height needs engineering, so treat the rate as a planning estimate. Timber at $24: 180 × $24 = $4,320. Drainage at $12: 180 × $12 = $2,160. Total: $6,480, before design fees.

The third example is where timber loses its price advantage. A 6-foot timber wall needs a designed post embedment and often a deadman or geogrid, and the engineering cost lands on a wall that will still need replacement in 20 years.

## Why Timber Is Cheap, and Where It Catches Up

Timber is cheap because the material is commodity lumber and the tools are a saw, a drill, and a level. There is no footing to pour, no crane to hire, and no block to deliver by the pallet. A two-person crew can build a low wall in two days.

The catch is service life. At 15 to 25 years, a timber wall built today will likely be replaced within the life of a mortgage. Using the 120-square-foot example, two builds at $3,360 each is $6,720 over 40 years, against one block wall at $15 to $35 per square foot, or $1,800 to $4,200, that lasts 50 years or more. That is not a reason to avoid timber; it is a reason to price it over the period you plan to stay.

Rot is concentrated at the soil line, where oxygen and moisture both exist. A post that is damp below grade and dry above decays at the transition, and the wall face follows as the post loses section. Ground-contact treatment and gravel drainage are what slow that process.

## Wood Versus Block

| Factor | Timber | Segmental block |
|---|---|---|
| Installed cost | $10–$25 per sq ft | $15–$35 per sq ft |
| Service life | 15–25 years | 50+ years |
| Height limit without engineering | About 4 feet | About 4 feet |
| Repairability | Replace boards or a post | Reset individual blocks |
| Appearance | Natural, ages to grey | Manufactured, consistent |
| Fire and pest resistance | Low | High |

For a low garden wall the timber premium buys nothing structural, so the cheaper option is rational. For a wall that holds a driveway or a terrace, block is the better long-term spend. The [timber versus block comparison](https://retainingwalllab.com/timber-vs-segmental-block/) works through the same trade-offs in more detail.

## How to Read a Timber Bid

1. Multiply wall length by height to get face area, then divide the bid by that number to compare per square foot.
2. Confirm the post size, spacing, and embedment depth, since these are where cheap bids cut corners.
3. Ask for the lumber treatment rating and species in writing, not just "pressure treated."
4. Check that the quote includes gravel, filter fabric, and a perforated drain, not just the wood.
5. Confirm whether haul-off of excavated soil and disposal of old material are included.
6. Ask for the permit line separately if the wall is at or above the local height threshold.

For the block alternative, see [retaining wall blocks cost](https://retainingwalllab.com/retaining-wall-blocks-cost/). For the drainage detail that decides how long either wall lasts, read [retaining wall drainage](https://retainingwalllab.com/retaining-wall-drainage/), and for the full material range, [retaining wall cost](https://retainingwalllab.com/retaining-wall-cost/).