A professionally installed retaining wall from Wall & Company typically costs $35–$100 per square foot of wall face.
For a typical 150-square-foot retaining wall, that means a planning budget of approximately $5,250–$15,000.
| Wall Face | Typical Price Range |
|---|---|
| 100 sq. ft. | $3,500–$10,000 |
| 150 sq. ft. | $5,250–$15,000 |
| 200 sq. ft. | $7,000–$20,000 |
| 300 sq. ft. | $10,500–$30,000 |
These are Wall & Company planning ranges based on the type of retaining walls we build in the Spokane area—not national averages.
The biggest factors affecting the final price are wall height, engineering requirements, equipment access, excavation, soil conditions, drainage and the type of retaining-wall system being installed.
How Is Retaining Wall Square Footage Calculated?
Retaining walls are generally priced according to the square footage of the wall face.
For example, a retaining wall that is 50 feet long and averages 3 feet high has approximately 150 square feet of wall face:
50 feet × 3 feet = 150 square feet
At Wall & Company’s typical $35–$100 per-square-foot range, that creates an initial planning budget of approximately $5,250–$15,000.
The visible wall, however, is only part of the project. Much of the construction that determines the final cost ends up underground or behind the finished wall.
How Does Wall Height Affect the Cost?
Wall height is one of the most important retaining-wall cost variables.
A two-foot landscape wall and a six-foot structural retaining wall aren’t simply different-sized versions of the same project. As height increases, so does the pressure exerted by the soil behind the wall.
Taller walls can require deeper excavation, larger foundations, additional drainage, geogrid reinforcement and engineering.
The four-foot threshold is also important in the Spokane area. Spokane County’s permit exemption generally applies to retaining walls not over four feet high, measured from the bottom of the footing to the top of the wall, provided the wall isn’t supporting certain additional loads or meeting other conditions.
That means the amount of wall visible above the ground isn’t necessarily its official height.
Engineering, permitting and additional structural requirements can significantly affect the price of taller retaining walls.
Why Does Equipment Access Affect Retaining Wall Cost?
Building a retaining wall requires moving a surprising amount of material.
Depending on the project, equipment can include:
- Mini excavators
- Compact track loaders or skid steers
- Plate compactors and other compaction equipment
- Dump trucks or dump trailers
- Material-handling equipment
Good access allows equipment to reach the wall location and efficiently remove excavated material, deliver gravel and drainage rock, and move retaining-wall block.
Restricted access can change that considerably.
A wall behind a home with a narrow side yard, fence, steep grade, septic system, mature landscaping or other obstruction may require smaller equipment and substantially more labor.
How Do Spokane Soil Conditions Affect Retaining Walls?
There is no single “Spokane soil.”
The Inland Northwest was shaped by volcanic activity, glaciers, ancient lakes and enormous Glacial Lake Missoula floods. As a result, excavation conditions can vary significantly throughout the Spokane area.
Spokane Valley sits over extensive flood deposits. The U.S. Geological Survey describes the Spokane Valley-Rathdrum Prairie aquifer as consisting largely of gravel, cobbles, boulders and sand deposited during catastrophic glacial floods. Those materials can provide excellent drainage, but large cobbles and boulders can complicate excavation.
Green Bluff has its own USDA-recognized soil series. Green Bluff soils are generally deep and well drained, with ashy silt-loam upper layers transitioning into increasingly gravelly and sandy material.
Five Mile Prairie and areas west of Five Mile include different flood deposits, including areas where USGS mapping identifies sand and silt deposited in lower-energy portions of the Missoula floods.
Indian Trail, North Spokane and surrounding hillsides can encounter different combinations of glacial deposits, native soils, rock and sloping terrain.
South Hill and the Latah Creek area can present yet another mix of slopes, rock, sand, silt and fine-grained ancient lake deposits.
These descriptions don’t tell us exactly what lies beneath a particular backyard. They demonstrate why an actual site evaluation matters when determining excavation and structural requirements.
Drainage Is Part of the Retaining Wall
Water behind a retaining wall creates pressure. Managing that water is therefore part of building the wall—not an optional landscaping detail.
Depending on the project, Wall & Company’s retaining-wall construction can include clean drainage aggregate, perforated drainpipe, proper backfill and positive drainage away from the wall.
The amount and complexity of drainage required can affect the total project price.
What Does the Wall & Company Price Include?
A retaining wall isn’t simply a row of attractive blocks.
Depending on the project, a Wall & Company retaining wall can include:
- Site preparation
- Excavation
- Mechanically compacted gravel foundation
- Base material compacted in multiple lifts
- Retaining-wall block or other selected material
- Drainage aggregate
- Perforated drainpipe
- Backfill
- Geogrid reinforcement where required
- Cutting and fitting
- Finish grading
- Cleanup
The exact construction specification depends on the wall height, site, soil, drainage conditions and loads the wall must support.
How Much Should I Budget for a Retaining Wall?
For a professionally installed Wall & Company retaining wall in the Spokane area, use $35–$100 per square foot of wall face as a realistic planning range.
A typical 150-square-foot wall would therefore have a planning budget of approximately $5,250–$15,000.
Larger, taller or more structurally complex retaining walls can exceed those totals.
The purpose of the range isn’t to replace an on-site estimate. It’s to give homeowners a realistic number before beginning the design and estimating process.
Frequently Asked Questions
How much does a 150-square-foot retaining wall cost in Spokane?
Using Wall & Company’s typical range of $35–$100 per square foot of wall face, a 150-square-foot retaining wall would generally have a planning range of approximately $5,250–$15,000.
How is the square footage of a retaining wall measured?
Multiply the wall’s length by its average height. A 50-foot wall averaging three feet high has approximately 150 square feet of wall face.
Do retaining walls over four feet require engineering?
The four-foot threshold is important, but the requirements are more nuanced than simply measuring the exposed wall. Height can be measured from the bottom of the footing, and walls supporting additional loads may be treated differently. Engineering and permitting requirements should be determined for the specific project.
Does rocky soil make a retaining wall more expensive?
It can. Cobbles, boulders, shallow rock or difficult excavation can increase equipment time and labor. Actual conditions need to be evaluated on site.
Why does access matter so much?
Retaining walls require excavation and movement of substantial quantities of soil, gravel, drainage aggregate and wall material. Restricted equipment access can increase the amount of labor required.
Does the price include drainage?
Proper drainage is part of professionally constructing a retaining wall. The specific drainage system depends on the wall and site conditions.