Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Kohler Home Additions & ADU: The Miami Owner’s Guide
Kohler home additions and ADU construction in Miami typically run $53,100 to $153,400 for a full build, depending on square footage, foundation work, and fixture packages. We stock and install Kohler fixtures, faucets, shower systems, and bath hardware as part of every addition or ADU we build, and we can usually source and set the plumbing rough-ins within two to three weeks of permit approval. Most homeowners discover they need this page because a Kohler fixture in an existing addition has failed, or because they’re planning new living space and want the fixture spec locked before the slab gets poured.
Kohler’s product line covers a lot of ground: Purist, Artifacts, Sous, Composed, Loure, and the budget-friendly Coralais line. Each series has its own valve bodies, trim kits, and rough-in dimensions, and that’s where additions get complicated. A Kohler Artifacts tub filler does not bolt onto a Kohler Coralais rough-in valve. The trim kits look similar in the catalog, but the stem extensions and cartridge seats are different by millimeters. If you’re adding a bathroom to a Miami home and the plumber roughs the Kohler valve at the wrong depth, you’ll find out when the trim plate floats a quarter inch off the tile. In Coconut Grove, where we’ve remodeled plenty of older homes, we’ve had to open finished walls to move a valve that was set too deep because someone guessed at the rough instead of checking the spec sheet.
Key takeaways:
- Kohler home additions and ADUs in Miami cost $53,100 to $153,400 installed, with the range driven by foundation type, bathroom count, and fixture tier.
- Kohler fixtures are series-specific: a Purist cartridge won’t fit a Coralais valve body, even when both are “Kohler.”
- We write the price before any work starts and the number on day one is the number on the invoice.
- If a Kohler fixture fails inside the first year, we come back and fix it at no charge under our 365-Day Done Right Promise.
Which Kohler Models This Applies To
We work across the full Kohler residential lineup in Miami, but most of what we install in additions and ADUs falls into four series: Purist (contemporary, minimalist trim), Artifacts (traditional, high-arc spouts), Composed (a step between the two, clean but not stark), and Coralais (Kohler’s value line, solid but simple). Each series has its own valve architecture. Purist and Composed share the Rite-Temp pressure-balancing valve standard, but the trim kits are not interchangeable between the two: the screws, collars, and stem lengths differ. Artifacts uses a larger ceramic disc valve on many models, and Coralais runs a simpler cartridge that Kohler has updated twice since 2015.
If you’re adding square footage or building an ADU behind a Miami house, the easiest path is to pick the Kohler series first, then build the rough-in around that exact model number. The model number is stamped on the underside of the faucet body or on the shower trim plate. Take a photo of it before you call anyone. That number, not the series name, is what confirms cartridge compatibility. When it comes to OEM versus aftermarket parts, we install OEM Kohler cartridges and valve bodies on every job. The aftermarket cartridges are cheaper, often by $20 to $40, but in Miami’s hard water (Biscayne Aquifer water runs high in calcium and magnesium) aftermarket seals fail faster. We’d rather put in the OEM part and back it with our one-year promise than save you $30 now and get a call in eight months.
Styles & brands we work with
Signs Your Kohler Home Additions & ADU Is Failing
- Water dribbles from the showerhead when the tub filler runs – this usually means the diverter cartridge is worn, common on Kohler Rite-Temp valves after 6 to 10 years of daily use in Miami water conditions. Corrosion builds on the diverter seat and it won’t seal completely.
- The handle turns too far or feels gritty – a gritty, loose handle means the pressure-balancing cartridge is starting to seize. In Miami, mineral scale is the leading cause: calcium deposits score the internal cylinder and the handle loses its stops.
- The temperature suddenly spikes or drops without touching anything – this is a failing pressure-balancing unit, and it’s a safety issue. Kohler’s balancing spool wears over time, and without it, a toilet flush elsewhere in the house can turn the shower into a scalding hazard.
- Small leaks at the base of the faucet – on Kohler widespread lavatory faucets, this is a worn stem o-ring or a crack at the supply line connection. Miami’s humidity means condensation builds inside cabinet bases and accelerates rubber degradation.
- The fixture won’t shut off completely – a slow drip from the spout long after you turn the tap off is a cartridge failure. On Kohler Coralais lavatory faucets we see this at around the 8-year mark if the home has unfiltered Miami city water.
See the difference
Before
After
Before
After
Before
AfterReplacement Cost & What’s Included
A full Kohler home addition in Miami runs $53,100 to $153,400 depending on whether you’re adding a single bathroom suite or a multiple-room addition with a kitchenette. An ADU with a Kohler bathroom and kitchen runs $106,200 to $259,600. For Kohler-specific fixture replacement or rough-in work within those projects, you’re looking at $1,200 to $4,500 per bathroom as a line item on a larger construction contract. If we’re replacing a single failed Kohler cartridge without any other work, the installed price is typically $180 to $340, including the OEM cartridge, the service call, and our one-year guarantee on the repair.
What drives cost: the number of fixtures, whether we’re changing a flat (same rough-in, new trim) or a conversion (moving a valve, new tub or shower pan), and how much tile or drywall has to be opened to access the plumbing. Every job gets a written price before work starts, with parts and labor separated. The 365-Day Done Right Promise covers the work and the part for a full year: if the cartridge fails or a connection leaks in that window, we come back and fix it free. No service call fee, no re-inspection fee.
DIY or Call Us?
Changing a Kohler cartridge is not a job we recommend doing yourself unless you’ve done plumbing work before. The valve is under constant water pressure, and if the retaining nut is over-tightened, you can crack the valve body inside the wall, which turns a $250 repair into a $900 wall-opening job. That said, you can safely check a few things before calling: verify your water pressure at an outdoor spigot (anything over 80 psi is bad for Kohler valves and shortens cartridge life), check the shut-off valves behind the fixture to make sure they rotate freely, and take clear photos of the model number before you call so we bring the right part on the first trip.
If the handle is gritty, the temperature is spiking, or water is dripping after you close the tap, call us at (850) 988-7559. We’ll bring the OEM Kohler cartridge, confirm the model on site, and have it fixed in a single visit. Trevor Nash has a thing about giving you a number first, then picking up the tools. You’ll know what the repair costs before we start turning the water back on.
FAQs
In Miami’s hard water, an OEM Kohler cartridge typically lasts 8 to 12 years. Unfiltered municipal water shortens that to 6 to 8 years because mineral scale accelerates seal wear. Call (850) 988-7559 if your fixture is inside that range and acting up; we’ll give you an exact quote before any work starts.
On some older Kohler valves you can clean and reseat the cartridge, but on modern Rite-Temp units, once the internal seals score, replacement is cheaper than repair. We don’t charge to assess the cartridge: if it’s salvaged, we’ll tell you, and the price reflects that.
Most single-fixture cartridge replacements take 45 to 90 minutes. A full fixture swap (faucet, valve, drain) runs 2 to 4 hours. If we’re roughing new Kohler plumbing into an addition or ADU in Miami, the rough-in phase for a bathroom takes a day to two days before inspection.
We carry the most common Kohler Rite-Temp cartridges, Purist and Coralais stems, and trim screws on the truck. If your model number requires a less common part, we order OEM direct and schedule the install as soon as it arrives. We also work with KraftMaid, Cambria, and Silestone for the surrounding finishes.
Written by Trevor Nash, Owner, Penhallow Remodeling Miami at Penhallow Remodeling Miami, serving Miami and nearby areas.
