100% money-backBook a walkthrough
Construction glossary · Sitework

What is retaining wallin construction?

A retaining wall in construction is a structure that holds back soil to create a grade change, letting a site carry two different elevations where a stable slope will not fit. Common commercial types are segmental retaining walls (SRW) built from dry-stacked block with geogrid reinforcement, cast-in-place concrete cantilever walls, and gravity walls that resist soil pressure with their own mass. Estimators measure walls in square feet of face or linear feet within a height class, because cost per foot climbs sharply as walls get taller.

Book a walkthrough Get a Free Takeoff

Free 30-minute walkthrough on your own drawings. No card.

Updated August 2026 · Reviewed by the Ruh construction team

Measured in sf of faceHeight classes 0-4, 4-8, 8+ ftLives in wall plan and profileCost driver geogrid tail length

How a retaining wall is measured

Block faceGeogrid tails 6 ftDrainage stone 1 ftWall drain6.67 ft design height120 lf x 6.67 ft = 800 sf face
The definition

Retaining wall, explained.

Retaining walls live on the civil grading plan and the wall plan and profile sheets, with the geotech report governing bearing, drainage, and global stability, and a structural design package for anything tall enough to require engineering (many jurisdictions trigger permits and engineered design around 4 ft of exposed height, though the threshold varies). Segmental block walls usually belong to the sitework or landscape contractor; cast-in-place walls go to the concrete contractor, so the same wall can land in two different bid packages depending on the type selected. The wall itself is only part of the assembly: excavation, a leveling pad, drainage aggregate, a perforated wall drain, filter fabric, geogrid, and reinforced backfill all ride along. The mistake new estimators make is pricing face area alone. Geogrid tails extend behind the face a distance set by the design (commonly on the order of 60 to 100 percent of wall height), and that tail length sets the width of the excavation and the volume of select backfill, which is frequently more money than the block itself.

How it is measured

Walls take off in square feet of face, length times height, with height including the buried embedment courses, not just the exposed face. Most estimators break the run into height classes (0 to 4 ft, 4 to 8 ft, over 8 ft) and carry a different unit cost for each, because a taller wall needs more geogrid, more select backfill, and engineered design. Supporting quantities: leveling pad in lf or cy, geogrid in sf from layer count and tail length, drainage stone in cy, wall drain in lf, and excavation and reinforced backfill in cy from the wall section. The plan gives length; the profile sheet, with top of wall and bottom of wall elevations station by station, gives the real height.

Worked example

A worked retaining wall example.

Worked example

Face area120 lf x 6.67 ft = 800 sf
Block wall (illustrative)800 sf x $38 = $30,400
Geogrid (illustrative)4 x 120 lf x 6 ft = 2,880 sf, x $1.60 = $4,608
Drainage stone (illustrative)120 lf x 1 ft x 6.67 ft = 800 cf, 800 / 27 = 29.6 cy carried as 30 cy x $55 = $1,650
Wall drain (illustrative)120 lf x $12 = $1,440
Wall total (illustrative)$30,400 + $4,608 + $1,650 + $1,440 = $38,098
How Ruh handles it

How Ruh handles retaining wall.

100%

Try Ruh on a real bid. 100% money-back guarantee if you are not satisfied.*

*Scoped delivery, terms apply. Read the guarantee terms

Start with a walkthrough

Retaining wall: frequently asked questions

How do you measure a retaining wall for an estimate?+

Measure length from the plan and height from the wall profile, station by station, using top of wall and bottom of wall elevations rather than a single typical height. Multiply to get face square footage, include the embedded courses below grade, and split the run into height classes so each class carries the right unit cost. Then quantify the support items separately: leveling pad, geogrid, drainage stone, wall drain, and reinforced backfill.

What is the difference between a segmental, gravity, and cast-in-place retaining wall?+

A segmental retaining wall is dry-stacked modular block, usually with geogrid layers tying the facing into the reinforced soil mass behind it. A gravity wall (large block, boulder, or gabion) resists overturning with sheer mass and needs no reinforcement at low heights. A cast-in-place cantilever wall is reinforced concrete on a spread footing, common where space behind the wall is tight. The type changes which trade prices it and what the supporting quantities look like.

When does a retaining wall need an engineer?+

Many US jurisdictions require a permit and an engineered design once exposed height exceeds about 4 ft, and sooner when the wall supports a surcharge such as a slope, driveway, or building above it. The geotech report and local code set the actual threshold. For estimating, an engineered wall means stamped drawings, specified geogrid lengths and embedment, and often special inspection, all of which belong in the price.

Still measuring by hand? Your next takeoff can run while you review this one.

See it on your plans

Related terms

GeotextileExcavationGradingFrench drainretaining wall backfillCompaction

Keep going: read the full guide or explore AI construction takeoff and estimating software.

The Sitework estimating cheat sheet
Every unit, waste factor, and conversion on one page. Free PDF.
Previous term
Proctor test
Next term
Riprap

Figures on this page are illustrative. Construction estimates depend on project-specific conditions, source documents, market pricing, and professional judgment. Ruh's AI assists the estimator and does not replace professional review: your team reviews, validates, and approves every estimate, bid, and pricing decision.

100% money-back guarantee

Try Ruh on a bid you are pricing now.

Put your next takeoff on Ruh.