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Quikrete Home Additions & ADU: The Los Angeles Owner's Guide
Planning a home addition or ADU in Los Angeles means choosing the right concrete product from the start, and for most foundations, footings, and structural slabs we install, Quikrete is the default choice. A full foundation pour for a Los Angeles ADU or room addition using Quikrete products typically lands between $53,100 and $153,400 when you include excavation, forming, concrete, reinforcement, finishing, and all required inspections. Most owners don't discover a Quikrete problem until the concrete has already been poured, set, and started to show hairline cracks, spalling, or settling at a corner months after the forms came off.
We're an independent remodeling contractor in Los Angeles, not affiliated with Quikrete. When a Quikrete-based foundation, footing, or slab on an addition or ADU fails, we're the crew that comes out, tells you honestly whether it needs to be cut out and repoured or whether it can be stabilized, and gives you a written price before a single tool leaves the truck.
Which Quikrete Models This Applies To
Quikrete doesn't make a single "home additions & ADU" product. It makes a family of concrete mixes and related materials, and the one your addition or ADU needs depends entirely on the structural job it's doing. Here is the honest breakdown of what we use where, and where things go wrong.
- Quikrete 5000 (high early strength): Our default for Los Angeles footings and foundation walls that need to bear real weight. It hits 5,000 psi compressive strength, which is what LA Department of Building and Safety engineers want to see on most residential foundation work.
- Quikrete Crack-Resistant Concrete Mix: Used for interior slabs and smaller patio bases tied to an addition. The polymer fiber reinforcement helps with shrinkage cracks, but it is not a fix for poor soil prep.
- Quikrete Concrete Mix (standard 4000 psi): Fine for non-structural pads and walkways around the addition, but we won't put it under an occupied living space in Los Angeles without engineer approval.
- Quikrete Fast-Setting Concrete Mix: Best for fence posts and gate posts around the property, not for anything that holds up a bedroom.
- Quikrete All-Purpose Gravel and Sand: The base layer matters as much as the concrete. Poor gravel compaction under a Los Angeles ADU slab is the number one cause of early cracking and settling we see.
The aftermarket vs. OEM question is different for concrete than it is for a faucet or a cabinet hinge. Quikrete is the brand you'll find at nearly every Los Angeles lumberyard and home center, and the bags have batch numbers printed along the bottom seam. The real "part" isn't just the concrete bag, it's the whole assembly: gravel base, vapor barrier, rebar or wire mesh, and the mix itself. When we match a failed pour, the batch number tells us the age, the plant, and the mix design. Aftermarket concrete mixes can work, but for anything structural on a Los Angeles addition or ADU, we specify the product by name in our written estimate so you know exactly what you're getting.
Styles & brands we work with
Signs Your Quikrete Home Additions & ADU Is Failing
- Hairline cracks running in a diagonal from a corner of the foundation within the first 12 months. This usually means the concrete cured too fast in Los Angeles heat or the subgrade wasn't properly compacted before the pour. Hairline might be cosmetic, but we'll measure it and tell you.
- One corner of the slab sits visibly lower than the others, and a door inside the addition starts sticking. Settling. The concrete didn't fail, the soil beneath it did. In Los Angeles, we see this most in hillside areas like Echo Park and Mount Washington, where poorly compacted fill gives way.
- Spalling, which is the concrete surface flaking off in small patches. Water got into the concrete's surface pores and pushed the top layer apart. Common near the coast in areas like Westchester and Playa del Rey where salt air is in play, and worse when the pour happened on a hot day without proper curing.
- Efflorescence, the white chalky deposit you see on concrete block or poured walls. It means moisture is moving through the wall. Not structurally dangerous on its own, but it tells us a waterproofing step got skipped.
- A visible gap opening between the addition's slab and the original house's foundation. The two structures are moving independently. We see this in Los Angeles neighborhoods with expansive clay soil, like parts of the Valley, where seasonal wet and dry cycles cause lift and shrink.
See the difference
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After
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AfterReplacement Cost & What's Included
A full concrete teardown and replacement for a failing ADU foundation or addition slab in Los Angeles typically runs $53,100 to $153,400. That is a wide range because no two Los Angeles lots are the same. Here is what moves the price.
- Access: A backyard ADU in West Adams with a 36-inch gate takes longer and costs more than a front-facing addition with driveway access. Equipment gets smaller, labor hours go up.
- Soil correction: If the original pour failed because of poorly compacted fill, we have to dig it out and start over with engineered fill. That alone can add $15,000 to $30,000 in Los Angeles hillsides.
- Structural engineering: LA Department of Building and Safety requires stamped plans for foundation work on any occupied structure. You'll pay a California licensed structural engineer separately, typically $2,500 to $6,000 depending on project size.
- Seismic reinforcement: Los Angeles is Seismic Design Category D. Rebar schedules and hold-down detailing are tighter here than almost anywhere else in the country, and that steel costs real money.
- Site clearance and debris hauling: Cutting out a failed slab means jackhammering, concrete disposal, and dump fees. Los Angeles transfer stations charge by the ton.
Every estimate we give includes the full scope in writing: demolition, hauling, gravel base, vapor barrier, steel, Quikrete mix specified by name, pour, finishing, cure time, and inspection coordination. The price on the estimate is the price on the invoice. If something fails inside the 365-Day Done Right Promise period, we return and fix it at no charge. That is in writing too.
DIY or Call Us?
Mixing and pouring a Quikrete bag for a mailbox post is a weekend job. Cutting out, forming, reinforcing, and pouring a structural foundation for an occupied addition or ADU in Los Angeles is not. The risk isn't just a crooked pour. It's a concrete assembly that fails inspection, costs you a stop-work order, or cracks six months after the first tenant moves in. Any structural concrete work that supports living space needs a permit in the City of Los Angeles, and the inspector will check the rebar before a single bag gets poured.
What you can do safely: clear debris from around the affected slab so you can see the full crack pattern, photograph everything with a tape measure in frame for scale, and check that drainage is moving water away from the foundation. If you see water pooling against the slab, that is your first problem to fix, regardless of the concrete's condition. For anything beyond that, call us at (213) 277-6578. Trevor Nash will look at it, tell you what is actually wrong, and give you a written number before anyone picks up a tool.
FAQs
A properly poured, properly cured Quikrete foundation in Los Angeles should last 50 years or more before any significant structural work is needed. The concrete rarely fails on its own. The subgrade below it gives way first, and a poured foundation is only as good as the ground it sits on.
Sometimes. Hairline shrinkage cracks under 1/8 inch wide can often be sealed and monitored with no structural work needed. Cracks wider than 1/4 inch, or cracks that are still moving, usually need a structural solution, which may mean piering, slabjacking, or cutting out and repouring portions of the slab. Call (213) 277-6578 and we'll tell you which camp you're in.
Most Los Angeles ADU foundation replacements take 3 to 6 weeks from demolition to final inspection. A week gets burned on demolition and grading, another on forming and steel, then the pour and a 7-day cure window before framing can begin. Inspections happen at each stage, and the LA Department of Building and Safety schedule controls the pace.
We stock Quikrete 5000, standard Concrete Mix, and Crack-Resistant Mix on our Los Angeles trucks for slab pours and footing repairs. We bring the specific product specified in your written estimate on schedule, not stored indefinitely in a truck bed. For larger pours, we order directly from our supplier with the batch number recorded.
If your Quikrete foundation, footing, or slab on a Los Angeles addition or ADU is showing signs of trouble, call (213) 277-6578 for a free estimate. We'll give you a number first, then pick up the tools.
Written by Trevor Nash, Owner, Penhallow Remodeling Los Angeles at Penhallow Remodeling Los Angeles, serving Los Angeles and nearby areas.
