When does a retaining wall need an engineer or a permit?

It depends on the city and the height. In Denver, any wall over 12 inches needs a zoning permit, walls over 4 feet need a building permit, and structural calculations are required once a wall retains more than about 2 feet of soil. Lakewood requires a permit above 30 inches, or when the wall holds up a driveway or slope. We check your city’s rules and bring in an engineer when the wall needs one.

Poured concrete or block?

Block walls work well for low garden walls. A poured, reinforced concrete wall is stronger for its thickness, handles taller grades and surcharge loads like a driveway above, and lasts for decades with good drainage behind it.

Why do retaining walls lean or crack?

Water. Saturated soil pushes on a wall far harder than dry soil, and a wall without drain rock, a drain pipe and weep holes slowly tips. An undersized footing makes it worse.

Can a leaning retaining wall be fixed?

Small cracks in a sound wall can be sealed. A wall that is already leaning usually has a failed footing or no drainage, and rebuilding it with both is the lasting fix.

Retaining Walls in Denver and the Front Range

Retaining Walls

Hold the grade. Give the water a way out.

Retaining walls fail from the water behind them more often than from the soil. We build reinforced concrete walls on a proper footing, with drain rock, a perforated drain and outlets so the hill stays where it is. Taller walls usually need an engineered design and a permit, and we’ll tell you up front when yours does.

Typical price$30–$45 / sq ft of wallinstalled · free written estimate

(720) 459-9091

How we build a retaining wall

What we build

Retaining Walls, start to finish

Poured concrete retaining walls
Terraced and tiered walls
Seat walls and planter walls
Wall drainage and outlets
Replacing failed timber or block walls

Key considerations

What goes into it

01Footing below frost depth
02Rebar in footing and stem
03Drain rock and perforated pipe
04Weep holes or outlets
05Engineering where height requires it

Good concrete starts long before the truck arrives. Our experienced team knows what to look for, what questions to ask, and which details can make the difference years down the road.

How the wall works

A retaining wall that drains

Not to scale · engineered where height requires

1Soil pushes on the wall, and saturated soil pushes much harder. Water is what tips most walls.

2Free-draining rock behind the wall, wrapped in fabric so the soil can't clog it.

3A perforated drain at the footing carries collected water out to daylight.

4A reinforced footing and stem, with the footing set below frost depth.

5Weep holes let any water that reaches the wall pass through instead of building up behind it.

How it runs

Estimate to final walkthrough

1Site and grade assessment
2Design and written scope
3Excavation, footing and wall forms
4Pour, drain, backfill and walkthrough

Finish options

Straightforward or decorative

Broom finish

Fine ridges for traction on snow and ice. The standard for driveways and walks.

Stamped

Patterned to look like stone, slate or brick, at a fraction of the cost.

Integral color

Color mixed through the concrete, so chips and wear don’t show grey.

Sealed

A penetrating sealer before the first winter to resist water and de-icer.

Where you live changes the job

A retaining wall on bentonite clay is a different job than one on river sand

The Front Range has four distinct ground conditions, and each one changes how we prepare the base, reinforce the slab and handle water. Your community page has the specifics.

Expansive clay plains

Remove the soft and organic soil, bring in compacted road base, set rebar on chairs, and plan joints and slope so water runs away from the house instead of soaking the clay beside it.

Denver Aurora Centennial Highlands Ranch

Foothills and tilted bedrock

Deeper excavation and a thicker compacted base, reinforcement sized for uneven support, and drainage that intercepts runoff above the slab, often paired with a retaining wall where the grade demands it.

Lakewood Boulder Golden Morrison

River sand and gravel

Compaction done in lifts, geotextile fabric where the native soil is soft, and a thicker section anywhere a truck, trailer or RV will park.

Longmont Commerce City Wheat Ridge Brighton

Palmer Divide uplands

Air-entrained exterior mix, proper curing, a penetrating sealer before the first winter, and a broom texture for traction on sloped driveways.

Parker Castle Rock Castle Pines Elizabeth

Questions about retaining walls

Retaining Walls: what people ask us

Poured concrete retaining walls usually run $30–$45 per square foot of wall face, or about $90–$180 per linear foot for a 3 to 4 foot wall, including the footing, rebar and drainage. Taller walls, engineering, tight access and decorative faces cost more.

Typical prices for every kind of project are in the Denver concrete cost guide, and general questions are on the FAQ page.

More ways to improve your property

Explore our concrete services

Concrete DrivewaysA better driveway starts from the ground up.Concrete PatiosAn outdoor room you’ll actually use.Concrete WalkwaysSafer paths, cleaner lines.Concrete FloorsGarage, shop and basement floors that hold up.Pads & SlabsSmaller project, big peace of mind.Athletic CourtsA court in the backyard, built to play on.Pool DecksSafe when wet, cooler underfoot.

Get a clear price on your retaining wall.

You'll know, without question, what your project involves, what it costs, and what to expect before work begins.