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Cambria Home Additions & ADU: The West Covina Owner’s Guide
Cambria home additions and ADU construction in West Covina typically run $45,000 to $130,000 for an addition, and $90,000 to $220,000 for a full ADU build. We plan, permit, and build these projects with Cambria quartz specified for the kitchen and bath surfaces, and we can usually start design work within a week of your call. Most West Covina homeowners reach out to us when they’ve outgrown their floor plan or want rental income, but they’re worried about city setbacks, soil movement, and whether their existing slab can handle the load.
If you’re reading this, chances are you’ve got a Cambria countertop or island in a home that no longer fits your life. Maybe the kitchen isn’t the problem, it’s the house around it. That’s where this gets interesting.
Which Cambria Models This Applies To
Cambria quartz comes in over 200 design series, but the products we work with most in West Covina additions and ADUs are the matte-finish designs like Brittanica, Torquay, and Ella, plus the newer high-traffic series built with Cambria’s proprietary gloss control. The thing to know: Cambria slabs are all 1cm, 2cm, or 3cm thickness depending on the series, and your existing countertop thickness dictates what we can match in an addition. A 3cm slab can sit directly on cabinets without plywood underlayment. A 1cm slab cannot. If you’re extending a kitchen or adding a prep area and want it to look seamless, we measure the existing thickness before we ever place the slab order.
For ADUs, we typically spec 2cm or 3cm Cambria because the smaller footprint benefits from a counter that doesn’t need edge buildup. Cambria is a premium quartz product, not a budget veneer, so it holds up to the hard water common in West Covina better than most sealed granites. That matters in an ADU that might sit vacant between tenants or be used by aging parents who don’t want to worry about sealing a countertop every year.
Mason Remodeling Co West Covina is an independent design-build contractor, not a Cambria dealer or affiliate. We buy Cambria through the same specification-grade supply chain we use for KraftMaid and Silestone, which means you get the real slab with the Cambria serial-numbered warranty registration, not a mislabeled import.
Styles & brands we work with
Signs Your Cambria Home Additions & ADU Is Failing
- Seam separation at the island overhang. Quartz doesn’t flex, but the cabinetry under it does. In West Covina, where summer heat cycles hit 90-plus degrees and winter nights drop into the 40s, wood framing expands and contracts enough to pop a seam that was cut too tight. If you can catch a fingernail on the seam, moisture is getting in and the seam will only widen.
- Hairline cracks radiating from a sink cutout. This is almost always an installation issue, not a Cambria defect. If the fabricator cut the sink opening with sharp inside corners instead of radiused ones, stress concentrates right there. We see this in older West Covina homes where the original counters were installed over cabinets that have since settled.
- Bowing or sponginess in the middle of a long run. Quartz needs support every 24 to 30 inches. If a previous contractor skipped the plywood subtop or spaced the cabinet rails too wide, the slab sags slightly. You won’t see the sag, but you’ll feel it when you lean on the counter and hear a faint tick.
- Chipping at the edge profile near high-traffic corners. Cambria is hard, but a sharp eased edge on a peninsula corner takes hits from hips, pans, and kids’ backpacks. Once a chip starts, it catches on clothing and gets worse. The fix is a re-edge, not a patch.
- Discoloration or clouding near the cooktop. Quartz can scorch if a hot pan sits directly on it. Cambria’s resin binder discolors at sustained temps around 300°F. If you have a dull white bloom near the range, that’s resin damage and it will not polish out.
See the difference
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AfterReplacement Cost & What’s Included
A Cambria-focused home addition in West Covina ranges from $45,000 to $130,000. A full ADU ranges from $90,000 to $220,000. Here’s what that money buys:
- Home addition ($45,000 – $130,000): architectural drawings, structural engineering, city permit fees, foundation and framing, roofing tie-in, rough and finish electrical, plumbing rough-in for wet areas, drywall, flooring, paint, Cambria countertop fabrication and install for the new space, and final inspection.
- ADU construction ($90,000 – $220,000): everything in the addition plus separate utility panel or subpanel, dedicated water and sewer connections, independent address and access, ADU-specific insulation and sound separation, full kitchen with Cambria counters, full bath, and all West Covina ADU ordinance compliance work.
- Garage conversion ($30,000 – $80,000): slab inspection and leveling, wall and ceiling insulation, window and door retrofits, full electrical, Cambria kitchenette or wet bar if the layout calls for it, and city sign-off.
The range is driven by three things: square footage, site conditions, and the finish level you choose. A 400-square-foot addition with a simple gable roof and one Cambria counter runs lower. A 700-square-foot addition requiring foundation reinforcement, a new electrical panel, and Cambria in the kitchen plus a wet bar runs higher. Either way, you get a written price before any work begins. We put the number in writing, and it does not grow unless you change the scope.
Every project is covered by our 365-Day Done Right Promise. If the work isn’t right within a year of completion, we make it right at no cost to you. That includes the Cambria seams, the cabinet alignment, the tile, all of it.
DIY or Call Us?
If your Cambria surface has a small chip, a cosmetic scratch, or a seam that’s slightly proud, you can live with it or have a stone fabricator touch it up. What you should not do is attempt to move, re-level, or re-seam a quartz countertop yourself. A 3cm Cambria slab weighs roughly 18 to 20 pounds per square foot. A 10-foot island can weigh 700 pounds. When a slab slips, it doesn’t just crack, it crushes whatever is underneath it. We’ve had to repair cabinet frames in West Covina because a well-meaning homeowner tried to shim a counter with a pry bar and cracked the face frame.
For a home addition or ADU, the answer is even clearer. This is structural work with permits, inspections, and engineering stamps. The city will not sign off on unpermitted square footage, and when you go to sell, undisclosed unpermitted work in West Covina becomes a title problem. If something is going to cost more or take longer, we tell you before the work starts, not after. You should know what you’re getting before we ever pick up a tool. Call (707) 760-7579 if you’re thinking about an addition or ADU.
FAQs
Cambria quartz itself carries a lifetime warranty from the manufacturer and will outlast the cabinets under it. What fails first in West Covina is the installation: seams, sink cutouts, and unsupported spans. Done right, expect 20-plus years of daily use with no sealing, no special cleaners, and no fading from the sun that beats on south-facing kitchens here. Call (707) 760-7579 for an honest assessment of your current counter before you decide whether to repair or replace.
Hairline cracks can sometimes be filled with a color-matched resin, but the repair is cosmetic and the underlying stress point remains. If the crack runs through a sink cutout or an inside corner, replacement is the only permanent fix. We’ll tell you straight up which one you’re looking at. Call (707) 760-7579 and we’ll send a crew member who can evaluate it in person.
A straightforward home addition runs 3 to 5 months from first shovel to final inspection. A full ADU runs 4 to 8 months depending on site access and utility work. Design and permitting add 4 to 8 weeks before construction starts. We keep the schedule honest, not aspirational. Call (707) 760-7579 to talk through your timeline and get a written price.
We don’t stock slabs on site, but we order through specification-grade supply partners with quick turnaround in the San Gabriel Valley. Cambria slabs are cut to order at fabrication facilities in the LA area, so typical lead time from template to install is 2 to 3 weeks. The cabinet lines we install, including KraftMaid and Silestone surfaces, come through the same channel, which keeps the whole kitchen schedule on one calendar. Call (707) 760-7579 to check current lead times for West Covina projects.
Call Mason Remodeling Co West Covina at (707) 760-7579 to schedule your free estimate. We’ll walk the space, answer your questions, and put the number in writing before any work starts. A live person answers, day or night.
Written by Isaac Pruett, Owner, Mason Remodeling Co West Covina at Mason Remodeling Co West Covina, serving West Covina and nearby areas.
