A low-cost concrete bag retaining wall typically costs $15-$45 per square foot of visible wall, or about $600-$1,800 for a 20-foot-long, 2-foot-high project. Bag price, wall height, drainage, site access, and whether labor is hired make the largest difference; taller or load-bearing walls may require engineering and a different construction method.
| Item | Low | Average | High | Notes |
|---|---|---|---|---|
| 20-foot wall, 2 feet high | $600 | $1,200 | $1,800 | Materials and typical installation |
| Concrete mix bags | $5 each | $7 each | $10 each | Common 60- to 80-pound bags |
| Installed wall area | $15/sq ft | $30/sq ft | $45/sq ft | Varies with access and prep |
| Drainage stone | $40/ton | $60/ton | $100/ton | Delivery may cost extra |
What a 20-foot concrete bag wall usually costs
For a straight, 20-foot wall about 2 feet high, a DIY build commonly runs $300-$800 for bags, base material, drainage, and basic tools. Hiring a small crew can bring the total to roughly $900-$1,800. These figures assume ordinary soil, straightforward access, and no major excavation or engineering.
Budget around $1,200 for a basic professionally installed wall of this size. The estimate assumes roughly 40 square feet of wall face and a modest concrete-bag installation, not a structural retaining wall carrying a driveway, building, or steep slope.
One 60-pound bag generally yields about 0.45 cubic foot of concrete; an 80-pound bag yields about 0.60 cubic foot. Actual bag count depends on wall thickness and how bags are laid. A 20-foot-by-2-foot face at 8 inches thick uses about 9 cubic feet before waste, or approximately 16-20 80-pound bags. Overlap, irregular ground, and thicker sections can raise that count.
Bag, base, drainage, and labor charges
Concrete bags are only one part of the quote. A stable base and a path for water to escape matter because trapped water can push a short wall out of position or accelerate damage in freeze-thaw climates.
| Quote item | Low | Average | High |
|---|---|---|---|
| Concrete bags | $5/bag | $7/bag | $10/bag |
| Gravel base and backfill | $40 | $100 | $250 |
| Drain pipe and fabric | $25 | $75 | $180 |
| Labor | $300 | $700 | $1,300 |
| Delivery and disposal | $0 | $100 | $300 |
Labor and site preparation can cost as much as the concrete mix. Contractors may charge $50-$100 per worker-hour, with minimum service fees of about $200-$500. Ask whether the quote includes digging, leveling, drain installation, and hauling excess soil.
How height, thickness, and drainage change the estimate
Wall height is a major cost and safety threshold. A 1- to 2-foot garden edge may need limited excavation, while a wall over 3 feet often needs more substantial design, drainage, and local review. Rules vary, and some jurisdictions count the buried portion or surcharge behind the wall when determining permit requirements.
Thickness also affects bag count: increasing a wall from 8 inches to 12 inches uses roughly 50% more concrete by volume. A run longer than 30 feet, a slope steeper than about 2:1, or soil that stays saturated can require extra base, drainage, or professional design. Do not treat a low bag price as proof that the wall is suitable for a heavy load.
Assumptions: Typical U.S. retail bag prices, a small straight wall, normal access, and no engineered reinforcement.
How long installation takes and what labor covers
A prepared 20-foot, 2-foot-high wall may take two people 1-2 days, including base work and drainage. Difficult digging, carrying bags far from a vehicle, or correcting an uneven slope can extend the job to 2-3 days. Bag stacking is physically demanding; the 60- to 80-pound weight can add handling time and labor cost.
Contractors may wet the stacked bags after placement, following the product instructions, or use another approved method. The exact process affects crew time. Request a written description of how the mix will be hydrated and protected while curing, rather than assuming the bags will harden reliably just from rain or ground moisture.
DIY bag walls compared with block and timber
DIY concrete bags can be economical for a short, low garden wall where appearance and long-term structural performance are not critical. Segmental retaining-wall block often costs more upfront, but provides a purpose-made system with predictable sizing and commonly available drainage details. Pressure-treated timber may have a lower material price for a small wall, but has a limited service life and can require replacement.
For walls holding back a driveway, building, pool, or substantial slope, a simple bag stack may be an inappropriate substitute for engineered masonry or reinforced construction. Compare installed cost and expected service life, not just the price per bag. A repair to an existing stable wall may be cheaper than replacing the full run, but bulging or leaning sections need assessment before patching.
Regional delivery and permit costs to check
Prices in major metro areas can be 10%-25% above smaller-market estimates because of higher labor rates, delivery minimums, and disposal fees. Rural locations may have lower labor prices but higher aggregate delivery charges when suppliers are far away. Local excavation conditions and freeze-thaw exposure also affect the amount of base and drainage work required.
Permit rules differ by city and county. A short landscape wall may not need a permit, while a taller wall, a wall near a property line, or one supporting a surcharge may trigger permits, inspections, or engineering fees. When required, allow roughly $50-$500 for permits and $300-$1,500 or more for engineering, depending on scope. Confirm local requirements before buying materials.
Three sample quotes for different wall sizes
| Project | Materials | Labor | Estimated total |
|---|---|---|---|
| 10 ft × 1 ft DIY garden edge | $150-$300 | $0 | $150-$300 |
| 20 ft × 2 ft, two-person crew | $400-$700 | 12-16 hours, $600-$1,200 | $1,000-$1,900 |
| 30 ft × 2.5 ft with extra drainage | $700-$1,200 | 24-32 hours, $1,200-$2,400 | $1,900-$3,900 |
These examples assume normal access and exclude unusual excavation, engineering, and permit costs. Compare quotes using the same wall length, height, thickness, drainage, and disposal scope.
Where homeowners can trim the concrete bag bill
Measure the wall face and planned thickness before ordering; excess bags are heavy and may not be returnable once opened. Keep the layout straight where possible, arrange materials close to the work area, and handle basic clearing yourself if the contractor agrees that it will not affect the warranty or site preparation.
Get at least three itemized quotes and compare labor hours, bag size, drainage materials, delivery, and haul-away charges. Avoid removing drainage or reducing wall thickness just to meet a budget. For a wall supporting significant soil, ask whether a purpose-built block or engineered repair provides better value than a low-cost bag assembly.