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Cambria Home Additions & ADU: The Los Angeles Owner’s Guide
Cambria home additions and ADU construction in Los Angeles typically cost $53,100 to $153,400 installed, depending on square footage, foundation work, and whether you’re building up, out, or converting a garage. That’s a wide range, but the number tightens fast once we see your lot, your setback requirements, and what you want the space to do. Most Los Angeles homeowners call us after realizing their existing footprint doesn’t work anymore – a growing family, an aging parent moving in, or a rental income opportunity the current floor plan can’t support. The part that “failed” isn’t a spring or a valve here. It’s the house itself, and the fix is structural.
We’re an independent Los Angeles contractor – not affiliated with Cambria – but if you’re planning a home addition or ADU, Cambria quartz is one of the surfaces we install most often in new kitchens, baths, and laundry rooms. We know how its slab sizes and weight affect framing, counter support, and sequencing. That matters when you’re adding 400 square feet and want the surface to look like it was always there.
Key Takeaways:
- Home additions in Los Angeles run $53,100 – $153,400; ADUs run $106,200 – $259,600
- Cambria slabs are heavier than most quartz – plan for reinforced cabinetry and specific seam placement
- LA setback rules, hillside ordinances, and soil conditions drive a big slice of the cost
- Written price before any work starts, every time, no exceptions
- Warranty: 365 days from completion date, in writing
Which Cambria Models This Applies To
Any Cambria design works in a home addition or ADU, but slab size and veining pattern change how we lay it out. Cambria’s standard slab is roughly 132″ x 65.5″ – bigger than many imported quartz brands – which means fewer seams on a 10-foot island or a long galley kitchen in a new ADU. Designs with heavy, directional veining (like Brittanicca, Ella, or Skara Brae) need book-matching and careful pattern flow across seams. Busier designs hide seams better if you’re doing a smaller galley kitchen on a budget. We walk you through this during the estimate, and Isaac Pruett has spent enough years on Los Angeles job sites to steer you toward a design that looks right for the space and the light.
The bigger compatibility gotcha isn’t the Cambria itself – it’s the substrate. A new addition on pier-and-beam or a garage conversion with a slightly out-of-level slab needs extra floor prep before a heavy quartz counter goes in. Cambria’s weight (about 16-18 lbs per square foot for a 3cm slab) is fine on properly supported ¾” plywood or existing concrete. It’s not fine on particleboard that’s seen moisture, or on cabinets that weren’t shimmed level after the addition settled. That’s the difference between OEM-spec installation and a shortcut we won’t take.
Styles & brands we work with
Signs Your Cambria Home Additions & ADU Is Failing
- Seam separation or lippage between slabs. This usually means the cabinets underneath shifted – common in additions where the subfloor wasn’t dried to spec before tile and counters went in. Los Angeles humidity swings between Santa Ana dry spells and coastal marine layers do this over time.
- Joints cracking at the transition between old house and new addition. If the foundation wasn’t pinned correctly, the two structures move at different rates. You’ll see hairline cracks at the roofline, along the floor line, or in drywall corners right where the addition starts.
- Doors and windows in the new space binding or sticking. That’s settlement speaking. Minor settling is normal in year one, but binding doors that get worse monthly suggest the foundation wasn’t engineered for the soil. LA’s expansive clay in some hillside neighborhoods makes this the #1 thing we check before designing an ADU.
- Counters or backsplashes pulling away from the wall. That gap grows when the wall behind them isn’t plumb – common in garage conversions where CMU block wasn’t furred out straight before finish work.
- Water staining or swelling at cabinet bases under the Cambria. A plumbing leak inside the addition, slow and unnoticed, destroys the cabinet platform the quartz sits on. You won’t see water on the stone itself. You’ll see the cabinet kick plate darken.
See the difference
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After
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AfterReplacement Cost & What’s Included
For a full Cambria home addition or ADU in Los Angeles, plan on $53,100 to $153,400 installed. That includes plans and engineering, permits, foundation and framing, roofing, electrical and plumbing rough-in, drywall, finish carpentry, and your Cambria surfaces installed in the new kitchen or bath. At the low end, you’re adding a single room bump-out with simple Saddlebar counters. At the high end, you’re building a full 2-bedroom ADU with a kitchen island, wet bar, and custom cabinetry carrying Brittanicca or a large-scale Cambria design.
What drives the spread:
- Square footage and second-story work (crane time, shoring, additional engineering)
- Foundation complexity – hillside lots, expansive soil, retaining walls
- Cambria design choice – standard designs cost less than the large-vein, high-drama quartz
- Kitchen and bath count inside the addition
- Permit fees and city-specific requirements (Santa Monica, Pasadena, and West Hollywood have their own planning hurdles)
Every project gets a written price before we start. That number covers parts, labor, permits, and the Cambria surfaces – no change orders, no surprise invoices. The work is guaranteed in writing for 365 days from completion date. If something’s not right in that year, we fix it at no cost.
DIY or Call Us?
Home additions and ADUs are not DIY projects. Framing, electrical, gas lines, and roof tie-ins can injure you or create a fire hazard if done wrong, and Los Angeles requires stamped engineering and permits for any addition over 120 square feet or any ADU. What you can do safely: measure your lot, pull your property lines, sketch what you want, and gather photos of Cambria designs you like. That prep work saves real money during the estimate because we’re not guessing at your intent.
Where owners get hurt is trying to act as their own general contractor. Sequencing trades for an addition is a full-time job, and a framing error buried behind tile becomes a $20,000 repair two years later. We’ve fixed those. If you’re ready to talk numbers, call (213) 632-5711. Isaac will walk the job with you and put the price in writing.
FAQs
Cambria quartz counters typically last 25+ years with normal use in Los Angeles, though direct sun exposure through south-facing windows in the new space can fade darker colors over 15-20 years just like any pigmented surface. The counter usually outlives the cabinets it sits on.
Call (213) 632-5711 if you want us to look at your addition’s sun exposure before you choose a design.
Most failing additions can be repaired – foundation pinning, re-leveling cabinets, reseating windows – but if the structural issue comes from unpermitted work or a foundation poured without engineering, rebuilding the affected section is often cheaper than chasing symptoms. We’ll tell you straight which one you’re looking at. Estimates are free, and you’ll have a written number either way.
A single-room addition typically takes 4-6 months from permit approval to final inspection; a full ADU runs 6-10 months depending on city review times and site access. Los Angeles plan check can add 6-12 weeks before we even start, and we’d rather set that expectation up front than let you find out in month three.
We source and install Cambria through our surface partnerships, which means we handle ordering, freight, layout, and installation as one line item. You don’t chase slabs or worry about a broken corner showing up in your driveway. Ask about KraftMaid cabinetry, Silestone, and Kohler fixtures while you’re planning the new space – we can quote it all together.
Know who’s coming, know what it costs, know it’s guaranteed – everything else is just noise.
Call (213) 632-5711 for a free estimate on your Cambria home addition or ADU in Los Angeles. We’ll put the price in writing before any work starts, and you’ll know exactly who’s coming to your door.
Written by Isaac Pruett, Owner, Mason Remodeling Co at Mason Remodeling Co Los Angeles, serving Los Angeles and nearby areas.
