







Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Wellborn Home Additions & ADU: The West Covina Owner’s Guide
Adding square footage to a Wellborn-outfitted home in West Covina typically runs between $45,000 and $130,000 for a standard room addition, while a full ADU with a Wellborn kitchen and bath lands between $90,000 and $220,000. We install and match Wellborn cabinet lines during additions, garage conversions, and ADU builds, and we can usually start a project within two to three weeks of the written estimate. Most West Covina owners reach out because they’ve outgrown their current floorplan and want to know whether their existing Wellborn kitchen can be extended, matched, or rebuilt into the new space without ripping everything out.

What you’re really asking is whether a home addition can feel like it was always there. That’s a fair question, because a bad addition shows itself in uneven transitions, mismatched cabinet heights, and a roofline that looks bolted on. We’ve done enough additions in West Covina neighborhoods like the tracts near Barranca Street and the older homes around South Hills to know that blending a new space into a Wellborn kitchen is more about measuring twice than wishing twice.
Which Wellborn Models This Applies To

Wellborn builds cabinetry across three primary lines: Estate, Premiere, and Cabinetworks. Estate is the full-custom line with the largest selection of wood species and door profiles. Premiere is semi-custom, which is what we see in most West Covina homes built or remodeled in the last fifteen years. Cabinetworks is the stock line, usually found in spec homes and quick flips. If you’re adding a kitchenette to a new ADU and want it to match your existing Wellborn kitchen, you’ll need the door style name, the finish code, and the exact cabinet box dimensions from the original order. That information is usually stamped on a label inside the sink base cabinet door.
One compatibility gotcha worth knowing: Wellborn changes finish formulations periodically, so a “Natural Maple” door from 2015 can sit a shade off from a 2024 order. For additions that tie directly into an existing Wellborn kitchen, we recommend carrying the original doors into the new run and ordering new doors for the less visible wall. That keeps the visible sightline seamless. Mason Remodeling Co West Covina is an independent service provider and not affiliated with Wellborn, but we order from their current catalogs and have a working relationship with several Wellborn dealers in the San Gabriel Valley.
Styles & brands we work with







Signs Your Wellborn Home Additions & ADU Is Failing
- Doors that no longer close square. This is almost always a settle issue in the original foundation or slab. Additions in West Covina’s clay-heavy soil are especially prone to this, because the ground expands and contracts with rain cycles. The cabinet box itself is usually fine; the floor under it moved.
- Drawer slides that bind or sag. Wellborn uses full-extension undermount slides on higher lines, and when those slides wear, the drawer starts to tilt. On a ten-year-old kitchen, slide replacement runs $18 to $45 per drawer in parts, and it’s a repair we can do in an afternoon.
- Hinge failure on heavy doors. The concealed European hinges Wellborn uses on Premiere and Estate lines have a lifespan of roughly 15 to 20 years under normal use, but doors with glass inserts or thick solid fronts wear them faster. You’ll notice the door drooping a quarter inch and scraping the lower cabinet frame.
- Water swelling along the toe kick or sink base. West Covina’s hard water is rough on finishes, but swelling is almost never the water itself. It’s a slow leak from a supply line or disposal connection that found its way under the cabinet. By the time you see it, the particleboard core in the cabinet base has already absorbed moisture and begun to expand.
- Finish fading or peeling on sun-facing runs. Cabinets under windows that catch the afternoon glare coming over the San Gabriel Mountains fade faster than anything else in a West Covina kitchen. Wellborn’s conversion varnish holds up well, but UV exposure in this climate will age a finish noticeably within seven to ten years.
See the difference
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After
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AfterReplacement Cost & What’s Included

Here’s the honest math for West Covina. A full home addition with a Wellborn kitchen install starts at $45,000 and can reach $130,000 depending on whether you’re adding a master suite, a family room, or a larger kitchen. An ADU with a small Wellborn kitchen and bath starts at $90,000 and runs to $220,000 for a two-bedroom unit with premium finishes. A garage conversion with a Wellborn kitchenette is the most affordable entry point at $30,000 to $80,000.
What drives the range is square footage, foundation work, roof tie-in complexity, and whether the Wellborn cabinetry is stock, semi-custom, or full-custom. Our written price includes all permits, demolition, framing, electrical, plumbing, drywall, flooring transitions, cabinet installation, and finish work. You see the full line-item breakdown before we start – not after. Every project carries our written guarantee for 365 days from the completion date, and if something fails within that window, we return and make it right at no charge.
DIY or Call Us?
If you’re adding a room, building an ADU, or converting a garage, this is not a DIY job. Foundation work, roof tie-ins, electrical panels, and plumbing rough-ins require permits in West Covina, and the city inspects each phase. You should know what you’re getting before we ever pick up a tool, and that means a written scope, a written price, and a clear permit path. Where an owner can save money is on finish decisions – picking stock Wellborn cabinets over custom, choosing a standard countertop depth, keeping the plumbing stack where it is. Those choices move the number more than any negotiation ever will.
If you’d rather have us handle everything, call (707) 760-7579 and we’ll walk the job with you. Isaac Pruett has worked on additions and ADU projects throughout West Covina for years, and we’ll give you a straight answer on what makes sense for your lot size and your Wellborn layout.
FAQs

Wellborn Premiere and Estate cabinets typically last 25 to 30 years in West Covina’s dry climate, with hardware like hinges and drawer slides needing replacement around the 15-year mark. The cabinet boxes themselves hold up well here because we don’t contend with coastal humidity, but sun exposure and hard-water mineral buildup in the sink area will age finishes and hardware faster.
Yes, matching existing Wellborn doors is common, but the finish age matters. We recommend pulling an existing door and bringing it to a Wellborn dealer to check against current finish samples. If the match is off, we’ll order new doors for a less visible wall and reuse your original doors in the new run so the sightline stays consistent.
A standard room addition tied into an existing Wellborn kitchen usually takes 10 to 16 weeks from permit approval to final inspection. A full ADU runs 16 to 26 weeks depending on foundation work and utility runs. We keep the schedule honest – if a delay is coming, we tell you before it hits, not after.
We stock common Wellborn hardware like concealed hinges, undermount drawer slides, shelf pins, and touch-up kits on our trucks, but doors and drawer fronts are ordered from Wellborn by size and finish. Call (707) 760-7579 and we’ll tell you over the phone whether it’s a same-day fix or an order-in part.
Written by Isaac Pruett, Owner, Mason Remodeling Co West Covina at Mason Remodeling Co West Covina, serving West Covina and nearby areas.


