Anyone can pour a slab. Not everyone can pour one that's still flat and crack-free in ten years. In a city with as much expansive clay soil, hillside lots, and older infrastructure as Los Angeles has, the difference shows up fast. Here's what actually separates a contractor worth hiring from one you'll be calling back in eighteen months.

Start with the license, not the truck

Any concrete contractor working in California on a job over $500 needs a CSLB license, and for this trade that's usually a C-8 classification. It takes about thirty seconds to look up a license number on the CSLB website and see if it's active, what class it's under, and whether there are complaints against it. Ask for the number before you ask for a bid. If someone hesitates or hands you a business card with no license number on it, that's the end of the conversation, not the start of a negotiation.

Ask about insurance too, specifically general liability and workers' comp. If a crew member gets hurt on your driveway pour and the contractor isn't covered, that liability can land on you as the property owner. A legitimate outfit will hand over a certificate of insurance without making it weird.

What's under the slab matters more than what's on top

A lot of the concrete problems I see in this city didn't start with bad concrete. They started with bad soil prep. Much of the LA basin sits on expansive clay, and it's especially pronounced in parts of the Valley, Sylmar, and Chatsworth. That clay swells when it gets wet in the winter and shrinks hard when it dries out in the summer. If a contractor skips proper compaction of the base, or doesn't bring in 4 to 6 inches of compacted class II road base before the pour, that movement transfers straight into your slab. You'll see it as cracking, heaving near the edges, or a patio that's suddenly not level with the back door.

On hillside lots in places like Eagle Rock or the foothill communities, drainage under and around the slab matters just as much. Water that pools against a foundation or retaining wall during a heavy January storm will find the weak point eventually. A contractor who asks about your grading and where water runs off your lot before quoting the job is thinking about the right things. One who just measures the square footage and gives you a number on the spot usually isn't.

Get the mix, the thickness, and the reinforcement in writing

A driveway that carries a car needs to be built differently than a walkway that carries foot traffic. Driveways here typically run 6 inches thick with rebar, often #3 or #4 bar on an 18-inch grid, because vehicle loads and the freeze-thaw-free but heat-cycle-heavy climate here still put real stress on a slab over time. Patios and walkways can usually get away with 4 inches and wire mesh, though a lot of contractors will still spec rebar because it holds position better during the pour and resists cracking better long term.

The concrete mix itself should be spelled out too, usually as a PSI rating. 3,000 PSI is common for patios and walkways. Driveways and anything bearing vehicle weight should be 3,500 to 4,000 PSI minimum. Ask what mix they're using and get it on the estimate, not just a verbal answer. If the bid just says "concrete" with no thickness, no PSI, and no mention of reinforcement, you're not actually comparing it to anything, you're just comparing prices, which is how people end up with the cheapest possible slab.

Control joints matter too. Concrete is going to crack somewhere, that's not optional, the only question is where. Cutting joints roughly every 8 to 10 feet, at a depth of about a quarter of the slab's thickness, gives the crack a place to happen where you won't see it. That cutting needs to happen within 24 hours of the pour, before the slab picks its own spot. If a contractor doesn't bring up joint spacing at all, ask about it directly.

Permits aren't a hassle, they're a checkpoint

In Los Angeles, most structural concrete work, slab foundations, retaining walls over a certain height, anything tied to an addition, needs a permit through the LA Department of Building and Safety, or through the local building department if you're in one of the surrounding cities that runs its own. A driveway apron that touches the public right of way often needs sign-off from the Bureau of Engineering as well, since you're working on city property at the curb.

A contractor who's been doing this a while treats the permit process as normal, not as extra paperwork to avoid. They'll expect an inspector to check the rebar placement and forms before the pour goes ahead, because once concrete is down, nobody can verify what's underneath it. If a contractor suggests skipping the permit to save time or money, understand what you're actually agreeing to: no inspection, no record, and a problem for you if you ever sell the house and it comes up in disclosure. If you're in an HOA community, which is common in newer developments out toward Santa Clarita or Valencia, check with them too before work starts, since some have their own approval process for driveway or patio changes.

Red flags worth walking away from

  • Full payment demanded upfront, before any material is delivered or work starts.
  • No written contract, or a contract that doesn't list thickness, PSI, reinforcement, and a timeline.
  • Pressure to sign the same day, especially from someone who showed up unsolicited after storm damage in your area.
  • A price that's dramatically lower than every other bid you got. Concrete, rebar, and labor cost roughly the same no matter who's pouring it. A number 40% below everyone else usually means something's getting cut, and it's not the price of gravel.
  • No mention of curing time. Concrete needs about 24 to 48 hours before you can walk on it and closer to 7 days before a car should drive on it, with full strength taking around 28 days. Anyone rushing you back onto a new driveway in two days either doesn't know that or doesn't care.

None of this is complicated once you know what to ask. A contractor who's done real work in this city will talk about your soil, your drainage, and your permit before they talk about price. If you want to see how we handle that on our own jobs around LA, take a look at our concrete contractor work.