The Spa Wet Room: Rebuilding the Primary Bath in Bethesda, Potomac, McLean & Great Falls

For years, the dream primary bathroom was about square footage: a big soaking tub on one wall, a glass shower on the other, and a lot of empty tile in between. The layout design-forward homeowners ask about now looks different. In Bethesda, Potomac, McLean and Great Falls, a primary bathroom wet room remodel replaces the tub-and-shower divide with a single, fully waterproofed zone: a curbless walk-in shower and a freestanding tub sharing one continuous, seamless floor.

For a high-end primary suite it makes sense. It reads as a private spa, it is easier to clean, and a curbless entry quietly future-proofs the home for aging in place. But a wet room is also one of the most technically demanding rooms a contractor can build. Done right, it is the centerpiece of the house for decades. Done wrong, it is a slow, expensive water problem hidden inside your walls and floor framing.

Here is how to think about a wet room in the DMV: what it is, what it typically costs, and what separates a build that lasts from one that leaks.

What a wet room actually is

A wet room is a bathroom, or a zone within one, where the floor and lower walls are waterproofed as one sealed envelope rather than only the inside of a shower pan. The shower has no curb and often no door; water runs to a linear or point drain set flush in a gently sloped floor. In a luxury primary suite, a popular layout puts a curbless walk-in shower and a freestanding tub together behind a single glass panel, sharing the same tiled floor.

The appeal is part looks, part function:

• It feels larger. Removing the curb, a second wall and the tub deck opens sightlines. A modest footprint can read as a suite.
• It is easier to clean. No curb to scrub, fewer grout corners, one continuous floor.
• It is more accessible. A zero-step entry removes a common trip hazard and works for walkers and wheelchairs, without the “medical” look of a retrofit.
• It hosts the wellness features people want. Steam, a rainfall head plus a hand shower, a built-in bench and layered lighting all live comfortably inside a wet room.

Why DMV homeowners are leaning in

A few things specific to our region make the wet room a strong fit.

First, housing stock. Many Bethesda, Chevy Chase and McLean homes were built or last renovated in an era of compartmentalized baths: a small shower, a separate tub alcove, a lot of beige tile. The bones are good and the lots are valuable, so many owners reinvest rather than move. Rebuilding a dated primary bath is one of the most noticeable ways to modernize a house you plan to keep.

Second, the aging-in-place calculus. Owners planning a premium renovation often intend to stay for the long haul. A curbless design lets them build accessibility in now, invisibly, instead of retrofitting later. If you are thinking about multigenerational living more broadly, our guide to basement in-law suites and ADUs in Montgomery County covers the other half of that plan.

Third, the palette. Warmer, quieter finishes (oatmeal, taupe, clay and muted sage with brass or matte-black fixtures) have been displacing cold gray-and-white, and they are exactly the materials that make a wet room feel like a retreat instead of a tiled box.

What a primary bathroom wet room remodel costs in Bethesda and McLean

Bathroom pricing varies widely by layout, finish level and how much plumbing moves, so treat these as hedged planning estimates, not quotes. In the DMV market, where skilled tile and waterproofing labor carries a premium, a reasonable way to budget is:

• A quality curbless walk-in shower conversion with mid-range finishes and frameless glass: typically somewhere in the low-to-mid five figures. Going curbless usually costs noticeably more than a comparable curbed shower, because the floor has to be recessed or built up to create a seamless transition.
• A full primary spa wet room (curbless shower plus freestanding tub, premium tile, radiant floor heat, custom vanity, relocated plumbing): in our experience, often in the range of roughly $60,000 to $120,000 or more for a large primary suite, driven heavily by tile selection and structural work. For a national reference point, JLC’s Cost vs. Value report prices its “upscale bath remodel” (a 100-square-foot bath with separate tub and shower) in the high five figures, and DMV labor rates tend to run above national averages.
• A steam generator and enclosure is a meaningful line item on top: equipment, a vapor-tight ceiling and door, a generator location, and dedicated electrical.

The drivers that move the number most: how far plumbing is relocated, the waterproofing system, the tile (large-format porcelain and natural stone behave very differently), and whether the floor structure can take the recess for a curbless entry without reframing. Radiant heat and steam also add electrical load; in an older house, confirm panel capacity early. Our 200-amp service upgrade guide for Bethesda and McLean explains how to find out.

The part that matters most: waterproofing and the floor

This is where a wet room is won or lost, and it is worth understanding before you hire anyone.

In a conventional bathroom, only the shower is waterproofed. In a wet room, the floor and lower walls become a continuous waterproof membrane, typically a bonded sheet membrane (Schluter-Kerdi is a well-known example) or a liquid-applied system, over a properly sloped substrate, with the drain integrated into that membrane. Every seam, corner and penetration has to be detailed to the manufacturer’s instructions. Water finds the weak point.

Two things make this harder in older DMV homes:

1. Recessing the floor for a curbless entry. On a slab it is one problem; over a wood-framed floor in a 1960s Colonial it is another, sometimes requiring joists to be modified or sistered, often with an engineer’s input. A good contractor opens up and checks this before promising “curbless.”
2. Ventilation and humidity. The Mid-Atlantic is humid for much of the year, and a steam shower adds a serious moisture load. Proper exhaust, the right substrate and a sealed steam enclosure keep moisture out of the wall cavity and mold out of the room. The same moisture discipline applies to other wellness rooms; see our guide to a home sauna and cold plunge suite in Northern Virginia.

On steam specifically: manufacturers and tile-industry guidance call for a vapor-tight enclosure, and a sloped ceiling is often recommended so condensation runs to the walls instead of dripping on the bather, depending on session length and ceiling finish. Follow the generator manufacturer’s installation manual.

The takeaway: a wet room is not a tile job with extra steps. It is a building-science project. Vet contractors for waterproofing experience specifically, not just pretty finished photos.

Permits and DMV logistics

A primary wet room almost always involves moving plumbing and adding electrical (heated floors, steam, lighting), so plan on permit-and-inspection work in all three jurisdictions:

• Montgomery County, MD: building and electrical permits run through the Department of Permitting Services, while plumbing permits and plumbing inspections are handled by WSSC Water, which requires most plumbing work, including interior re-piping, to be done by a WSSC-licensed plumber.
• Fairfax County, VA: the county lists bathroom remodels among interior alterations that need a permit, and new or relocated plumbing fixtures and electrical devices need trade permits.
• Washington, DC: the Department of Buildings directs kitchen and bathroom remodels to its Alteration and Repair permit, with plumbing and electrical handled under separate trade permits.

Scope thresholds and procedures change, so confirm your project with the relevant office (DPS and WSSC Water, Fairfax County Land Development Services, or DC DOB) before demolition. The rough-in and close-in inspections are a feature, not a hassle: they are the checkpoints that catch a bad detail before it is buried under tile.

In a condo or HOA community, interior bath work is often outside the association’s purview, but work touching shared plumbing stacks or in a multi-unit building can trigger review and scheduling rules. Check your governing documents first.

Plan the calendar realistically. A full primary wet room is commonly a multi-week project, and waterproofing membranes and setting materials have cure times, plus flood testing, that should not be compressed.

FAQ

Is a wet room a good idea in a humid climate like the DMV? Yes, as long as it is built with proper ventilation and a correctly installed waterproof membrane. Humidity makes those details more important, not less. Most failures trace back to a skipped detail, not the climate.

Does a curbless shower cost more than a regular one? Generally, yes. A zero-step entry requires recessing or building up the floor and careful slope-to-drain work, which adds labor and sometimes framing. The payoff is the look, easier cleaning and accessibility.

Will a spa bathroom remodel add value to my Bethesda or McLean home? It can help a home show and sell, but don’t plan on recovering the full cost. National resale surveys such as JLC’s Cost vs. Value report consistently show upscale bath remodels recouping well under their cost at resale. The strongest case for a wet room is how you will use it over the years you stay.

Can you add a steam shower to an existing bathroom? Often, yes, but it is more than a fixture swap. It needs a vapor-tight enclosure and door, a generator location and dedicated electrical, and it is best planned as part of a larger remodel.

How long does a primary wet room remodel take? Plan for several weeks of construction for a full primary suite, plus design, selections and permitting beforehand. Waterproofing and tile have cure and inspection steps that should not be rushed.

Build it once, build it right

A spa wet room rewards an experienced builder and punishes a cheap one. Karma Construction Group has been building and remodeling homes across the DMV since 2012, and we treat waterproofing and tile detailing as the core of the job, not an afterthought. We work in Maryland under MHIC #108917 and in Virginia under Class A license #2705178913; you can verify every license on our licenses page.

If you are planning a primary bath remodel in Bethesda, Potomac, McLean or Great Falls, let’s walk your space and talk through what is realistic for your home and budget. Call 202-798-7663 or request a free consultation at karmaconstructiongroup.com.