Retaining Wall Cost Per Linear Foot

The short answer: retaining walls typically cost $20 to $50 per linear foot for standard residential installations, but that number can swing dramatically based on wall height, material choice, drainage requirements, and whether you need geo-grid reinforcement or engineered plans.

If you’ve been handed a retaining wall job and someone asked you to quote it by the foot, you already know that single number doesn’t tell the whole story. A 2-foot timber border wall along a flower bed is nothing like a 6-foot CMU wall holding back a hillside. Both get quoted “per linear foot,” but the engineering, labor, and material costs are worlds apart. This guide breaks down what actually drives retaining wall costs so you can estimate them accurately and explain the price to your clients without losing the job or your margin.

Quick Answer: What Does a Retaining Wall Cost Per Linear Foot?

Here’s a material-by-material snapshot for typical residential retaining walls in the 3-to-5-foot height range:

Wall Type	Cost Per Linear Foot	Cost Per Sq Ft of Face
Timber (railroad tie or treated)	$15 - $30	-
Segmental block (Allan Block, Versa-Lok)	$25 - $70	$20 - $50
Concrete block / CMU	$40 - $90	$20 - $45
Poured concrete	$60 - $120	$30 - $60

These are installed costs including basic drainage, but not including excavation, geo-grid, or permits. We’ll get into each of those below.

Use the Retaining Wall Calculator to run a full material and cost estimate for your specific project dimensions and material selection.

What Actually Drives the Cost (It’s Not Just the Block)

Most contractors new to retaining walls make the mistake of pricing just the visible face of the wall. The block or timber you can see is maybe 40-50% of the total cost. Here’s where the rest goes:

Excavation and grading. Before you set one block, you’re moving dirt. On a 50-foot wall with a 4-foot height, you might excavate 10-15 yards of material depending on slope and base depth requirements. At $150-$300 per yard to haul off, that adds up fast. If you can push the material on-site, you save that cost, but you need somewhere for it to go.

Base preparation. Every wall needs a compacted gravel base, typically 6 inches of 3/4-inch crushed stone, wider than the wall’s footing. Skip this and the wall shifts.

Drainage. This is where walls fail. Behind every retaining wall, you need a drainage system: perforated pipe, drain rock (4-6 inches minimum), and filter fabric to keep fines out of the aggregate. Drainage adds $8-$18 per linear foot to the job depending on pipe size and aggregate costs in your area. You cannot skip this. Hydrostatic pressure behind an undrained wall will move anything you build.

Geo-grid reinforcement. Any wall over 3-4 feet tall in segmental block systems needs geo-grid embedded into the backfill. Geo-grid layers are typically installed every 2-3 courses depending on the manufacturer’s engineering tables. This adds material cost ($1.50-$4.00 per square foot of grid) and labor time for proper backfill compaction at each layer. On a 5-foot wall, you might have two geo-grid layers. On an 8-foot wall, you could have four or more.

Permits and engineering. Most municipalities require a permit for retaining walls over 4 feet in height. Engineered walls (anything structural, tiered systems, walls near property lines or structures) often need stamped drawings. Budget $500-$2,500 for engineering depending on complexity and your region.

Worked Example 1: Segmental Block Wall, 4 Feet Tall, 40 Linear Feet

This is a common residential job. Client wants a segmental retaining wall along their backyard slope.

Dimensions: 40 LF x 4 ft tall = 160 sq ft of wall face Material (segmental block at $4.50/block, 1.5 blocks per sq ft): 240 blocks x $4.50 = $1,080 Cap blocks: 40 LF x $3.00 = $120 Drainage pipe (4-inch perforated): 40 LF x $1.50 = $60 Drain rock (1/2 yard per 10 LF): 2 yards x $65 = $130 Filter fabric: 40 LF x $1.00 = $40 Geo-grid (one layer at 4 ft): 40 LF x 4 ft x $2.50 = $400 Crushed gravel base: 1.5 yards x $65 = $98 Labor (25 hours at $35/hr): $875 Excavation (minimal, already graded): $200

Total materials + labor: approximately $3,000, or $75 per linear foot

That works out to about $18.75 per square foot of wall face installed. Note that the block itself was only $1,080 of the $3,000 total. If you only priced the block and a markup, you’d lose money.

Worked Example 2: Poured Concrete Wall, 6 Feet Tall, 30 Linear Feet

This project involves a steeper slope and the client wants a clean poured wall. This requires forms, rebar, and a ready-mix truck.

Dimensions: 30 LF x 6 ft tall = 180 sq ft of wall face Wall thickness (8 inches): 30 LF x 0.667 ft x 6 ft = 120 cubic feet = 4.4 cubic yards Footing (12 inches wide x 12 inches deep): 30 LF x 1 ft x 1 ft = 30 cubic feet = 1.1 cubic yards Total concrete: 5.5 cubic yards x $155/yard = $853 Rebar (#4 bar, vertical and horizontal): approximately 350 LF x $0.65 = $228 Form rental (2 pours): $400 Drainage system: $600 Excavation (deeper for footing and drainage): $500 Labor (carpenter 20 hrs at $40 + laborer 20 hrs at $25): $1,300 Permit (6-ft wall, likely required): $350

Total: approximately $4,231, or $141 per linear foot

That’s a big number but a 6-foot poured concrete wall is a serious structural project. If someone gives you a budget number of $60/LF for this scope, they got a quote from someone who’s leaving out half the costs.

For the concrete portion of any project, run the numbers through the Concrete Calculator or check current pricing on our Concrete Cost Per Yard page to make sure you’re using current local pricing.

Block Types: Choosing the Right Material

Timber walls are the most affordable upfront but have the shortest lifespan. Treated lumber or railroad ties work fine for low garden walls (under 3 feet), but they’re not a great choice for structural applications. Expect 15-25 years before replacement in most climates. Don’t use railroad ties near vegetable gardens.

Segmental retaining wall block (Allan Block, Versa-Lok, Anchor Diamond, and similar systems) is the most popular choice for residential retaining walls. These systems are engineered. The manufacturers provide tables that tell you exactly when geo-grid is required, what setback each course needs, and the maximum height without engineering. Follow those tables. They exist because the systems have been load-tested, and deviating from them puts you in liability territory.

CMU (concrete masonry unit) block gives you a strong, durable wall that can be built taller with rebar-filled cores and poured grout. CMU walls look more industrial unless you add a finish, but they’re appropriate for commercial applications and anywhere you need a very strong wall with a specific engineered design.

Poured concrete walls require forming and a ready-mix truck but produce the strongest, most continuous wall. They’re the right call when you need a specific geometry, when the load is significant, or when the client wants a smooth finished surface they can stain or coat.

Pro Tips From the Field

Design drainage before you design the wall. Figure out where the water will go first. The drainage pipe needs an outlet. If there’s no good outlet, you may need a dry well or French drain extension. Discovering this mid-project adds cost and delays.

Compact backfill in 6-inch lifts. Don’t dump all the backfill in at once. Compact it in layers. If you skip compaction, the wall will settle and lean. On geo-grid walls, every grid layer has to be set at the right elevation, and backfill has to be compacted before you set the next layer.

Batter the wall. Most segmental block systems are designed to lean back into the hillside by 1 inch per foot of height. This setback is critical for stability. Don’t try to build a segmental wall perfectly vertical.

Pull a permit even when clients push back. Unpermitted retaining walls create title issues when the client sells. If the wall fails and injures someone, an unpermitted structure is a liability problem for everyone. Know your local thresholds and follow them.

Stone and terrain vary by region. Soil type matters enormously. Clay soil holds water and exerts more pressure than sandy soil. Rocky soil can make excavation cost double. Everything in this guide uses national average pricing; your local material costs, labor rates, and permit fees will vary.

Common Mistakes That Kill Margin on Retaining Wall Jobs

Forgetting the drainage run. The drainage pipe needs to daylight somewhere. That “somewhere” might be 30 feet away from the wall end. Did you include that pipe run in your estimate?

Underestimating excavation. On a sloped site, you’re not just digging a footer trench. You’re cutting into the hillside to create a level base, and that material has to go somewhere. Price it or lose it.

Missing geo-grid layers. The first time you bid without geo-grid because you didn’t know the rule of thumb (over 3-4 feet, you need it), and the client later gets a city inspection, you’ll be adding it at your own cost.

Quoting per foot without knowing the height. “Per linear foot” is a shortcut that only works if both parties agree on height, drainage, and material. Get the full scope before you give a number.

Not factoring block waste. On curves, corners, and cuts, expect 10-15% waste on segmental block. Build it into your material order.

FAQ

How much does a 100-foot retaining wall cost? A 100-foot segmental block wall at 4 feet tall runs roughly $6,000-$12,000 installed, depending on site conditions and drainage requirements. A poured concrete wall at the same length and height would run $10,000-$18,000 or more.

Do I need a permit for a retaining wall? Most jurisdictions require permits for walls over 4 feet in height measured from the bottom of the footing. Some areas set the threshold at 3 feet. Always check with your local building department. Walls near property lines, structures, or on commercial property often have lower thresholds.

When is geo-grid required? Every major segmental block system manufacturer publishes engineering tables. In general, any wall over 3-4 feet tall using segmental block requires geo-grid reinforcement. The tables specify grid spacing and embedment length based on wall height and soil conditions.

Why is drainage so important? Soil behind a retaining wall holds water. Water-saturated soil is significantly heavier than dry soil. Without drainage, hydrostatic pressure builds up behind the wall until it pushes the wall over or tilts it forward. A wall that fails after a heavy rain is almost always a drainage failure.

Can I use the per-square-foot price instead of per-linear-foot? Per-square-foot of wall face is often more accurate because it accounts for height. Many commercial projects price this way. Per-linear-foot is common in residential estimating for standard heights but always confirm the assumed height with your client.

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Retaining walls are one of those jobs where accurate estimating is the difference between a solid margin and a money loser. The material cost is just the starting point. Excavation, drainage, geo-grid, compaction labor, and permits are all real costs on every wall over a few feet tall.

Try EstimationPro free to build retaining wall estimates from site photos and notes, with AI-generated material lists and pricing that you can review and adjust before sending to clients.

For scope-based projects, read our guide on How to Estimate Construction Jobs for a full process walkthrough.

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