Who does what
| Role | License / credential | What they do |
|---|---|---|
| Concrete contractor | CSLB C-8 (scope) | Poured and board-formed concrete walls, footings |
| Masonry contractor | CSLB C-29 (scope) | Block and CMU walls; the scope covers structural load-bearing and non-load-bearing masonry walls |
| Landscape contractor | CSLB C-27 (scope) | Landscape work; the scope doesn’t name retaining walls, so confirm a structural wall is within their license |
| General contractor | CSLB Class A or B | Walls as part of larger projects; confirm the class fits the work |
| Civil / structural engineer | California registration | Designs permitted walls and repairs |
| Geotechnical engineer | California registration | Soils reports, slope stability, tiered walls |
Check the license
California requires a license for any job of $1,000 or more in labor and materials (CSLB bulletin). On the CSLB license lookup, confirm the license is active, the classification fits, and workers’ compensation and bond are on file.
Want to talk to a local wall contractor about your project?
What every bid should spell out
- Height, and how it’s measured (exposed vs. from the bottom of the footing).
- Footing size, depth and reinforcement.
- Drainage: drain rock depth, pipe size, filter fabric and where the pipe outlets.
- Backfill: what material, compacted in lifts.
- Engineering and soils report: included or separate, and who hires them.
- Permit: who applies and pays.
- Demolition and haul-off of the old wall and excavated soil.
- Access: equipment, hand-carry, protection of lawns and hardscape.
- Warranty in writing, with what it covers.
- Deposit and payment schedule, within California’s down-payment limit.
- Timeline, including inspection stops.
Red flags
Prices to sanity-check a bid are in the cost guide; jurisdiction rules are on permits by city. Ready to talk? Contact or call.
Common questions
What type of contractor does retaining walls?
Concrete contractors (CSLB C-8) build poured walls; masonry contractors (C-29) build block and CMU walls, which the classification describes as structural load-bearing and non-load-bearing walls. General contractors often take walls on as part of bigger projects. The C-27 landscaping classification doesn’t name walls, so ask a landscaper whether a structural wall is within their license. Engineers design walls; contractors build them.
Should the contractor or an engineer design my wall?
Above the permit line in Walnut Creek, a licensed architect or registered civil or structural engineer must design it. Many contractors work with an engineer they know; you can also hire one directly.
How much deposit should I pay?
California limits the down payment on a home improvement contract to $1,000 or 10% of the price, whichever is less (Business and Professions Code § 7159.5). Progress payments should follow completed work.
Sources
- CSLB C-8 Concrete classification
- CSLB C-29 Masonry classification
- CSLB C-27 Landscaping classification
- CSLB license lookup
- CSLB bulletin on AB 2622 (unlicensed work limit)
- City of Walnut Creek: Retaining walls
Checked October 2026. Rules and prices change; confirm with the agency or a contractor before you build.