Why the hiring decision matters more for retaining walls than most projects
A retaining wall that is built incorrectly does not always fail visibly right away. It can hold fine for three or four wet seasons and then lean, crack, or collapse after the fifth one. By that time, the contractor who built it may be unreachable. The repair cost falls on the homeowner.
This is not a reason to be paralyzed, but it is a reason to be deliberate about who builds your wall. The characteristics of a good retaining wall contractor are observable before the job starts, and the warning signs of a shortcut contractor are also observable if you know what to look for.
What license a retaining wall contractor needs in California
In California, general contractors (B license) and specialty contractors holding a C-29 (masonry), C-8 (concrete), or C-12 (earthwork and paving) license are qualified to build retaining walls depending on the scope of work. Some retaining wall projects also involve grading, which can require additional licensing.
Verify any contractor’s license before signing a contract. The California State License Board database at cslb.ca.gov lets you search by contractor name, company name, or license number. The database shows whether the license is active, what classification it covers, when it expires, and whether there are any complaints or disciplinary actions on record.
Never hire a retaining wall contractor who cannot provide a California license number. A contractor operating without a license cannot pull permits, which means any permitted wall would be built without the legal authority to do so, and you as the homeowner carry the liability.
Questions to ask before hiring
These questions are worth asking directly, before getting a quote.
Do you pull permits for walls over 4 feet? The correct answer is yes. A contractor who says permits are not necessary for your wall, or who offers to build the wall without a permit when one is required, is not a contractor you want to hire. Permitted walls have inspections. Inspections create documentation that the work was done correctly.
Who is your engineer for permitted walls? On walls over 4 feet, a licensed engineer must stamp the drawings. Some contractors have engineering relationships they work with regularly. Others coordinate with the homeowner to hire an engineer independently. Either approach works, but the contractor should have a clear answer about how engineering is handled.
What is behind the wall in your scope? The answer should specifically describe drain rock (not native soil), perforated drain pipe, and where the water exits. If the contractor says drainage is extra or does not describe it specifically, drainage is likely being underbuilt.
Have you built walls in this part of the county before? San Diego’s soil conditions vary significantly by location. A contractor who has built walls in similar soil conditions to your lot, whether coastal clay, inland decomposed granite, or expansive valley soils, will have relevant experience for your specific site conditions.
Can you provide references from similar projects? A retaining wall contractor who has been operating in the county for several years should be able to give you names and numbers of past clients in the same general area or with similar project types.
How to compare bids
A complete retaining wall bid should specify at minimum: wall material and manufacturer, wall length and height, whether drain rock and perforated pipe are included, whether engineering and permit are included (or explicitly excluded), backfill material and compaction specification, and any demolition of existing walls.
Low bids that leave out drainage, use vague language about materials, or exclude permits are not actually comparable to bids that include all of those items. Before comparing price, make sure you are comparing the same scope.
Some contractors give per-linear-foot prices and some give lump sums. Per-linear-foot prices are easier to compare across bids if the wall length and height are consistent. Make sure you know what the total linear footage is and what height each bidder is pricing.
Get at least three bids for any project over $5,000. For projects over $15,000, take the time to check references from at least one bidder before signing.
Red flags before the job starts
Demanding full payment upfront. California law limits deposit requirements for home improvement contracts to 10% of the contract price or $1,000, whichever is less. A contractor asking for more than that upfront is not operating within the law.
No written contract. All home improvement contracts over $500 in California must be in writing. A contractor who works on a handshake is working outside the required framework for your protection.
No license or insurance documentation. Ask for the license number and verify it on cslb.ca.gov. Ask for a certificate of insurance showing general liability coverage. Both should be provided without hesitation.
Offering to do the work without permits to save you money. On a permitted project, this offer saves the contractor time and saves you the permit fee, but it eliminates the inspection record that documents the work was done correctly. That documentation is worth significantly more than the permit fee.
What Wall Pro SD does
Wall Pro SD is a referral service. We connect San Diego homeowners with insured, experienced local retaining wall contractors across the county, from Oceanside and Encinitas in the north to Chula Vista and National City in the south, and inland to El Cajon, La Mesa, and Santee.
We do not hold a contractor’s license, and we do not perform the work. What we do is connect you with contractors who are insured, have local experience, and can handle the project from permit coordination through final inspection.
Call (858) 925-5546 to get connected with a local retaining wall crew that can come out to your property, measure the site, and give you a real quote.
For help understanding what type of wall fits your project, see our concrete block retaining walls and retaining wall inspection pages.