Curbless Shower Design Guide: Costs, Drainage, Waterproofing (Twin Cities 2026)

Ten years ago, a curbless shower was a custom request we'd get maybe once a year, usually from a client planning to age in place. Today, it's the default ask in almost every primary bath we remodel from Linden Hills to Highland Park. The look is cleaner, the space feels bigger, and once you've stepped into one without lifting a foot over a 6-inch dam, you don't go back. This guide walks through how we build them, what they cost in the Twin Cities, where they go wrong, and when we'll tell a homeowner to stick with a curbed pan.

What a curbless shower is and why they've overtaken curbed in primary baths

A curbless shower (also called a zero-entry or barrier-free shower) has no raised threshold between the bathroom floor and the shower floor. The tile runs continuously from the vanity out to the shower drain, with the slope built into the subfloor rather than dammed at the edge. The result is a single visual plane: no curb to trip on, no awkward step, no tile transition strip breaking up the floor.

In primary baths we remodel in Kenwood bungalows, Crocus Hill Victorians, and Edina Country Club rebuilds, curbless is now the request 8 times out of 10. The reasons are pretty consistent. It makes a small bath feel significantly larger because the eye reads one continuous floor instead of a chopped-up space. It pairs beautifully with frameless glass or no glass at all. It's easier to clean because there's no curb-to-floor joint collecting soap scum. And it future-proofs the bathroom for a wheelchair, walker, or just a 75-year-old version of yourself who doesn't want to high-step into a shower at 6 a.m.

The trade-off is that a curbless shower is harder to build correctly. There's no curb to catch errant water, so the waterproofing, slope, and drain placement have to be near-perfect. This is not a project where we'd cut corners or hand off to a general handyman. When we remodel a bathroom, the curbless pan is usually the most technically demanding part of the job.

Drainage options: linear drain vs traditional point drain

The drain decision shapes the entire shower. With a traditional point drain (the round or square drain in the center of the pan), the floor has to slope down from all four corners toward the middle. That means four separate sloped planes meeting at the drain, which on a curbless shower can look fine but creates compound angles that are tricky to tile cleanly with anything larger than a 2x2 mosaic.

A linear drain is a long, narrow channel (typically 24 to 60 inches) set against one wall or at the threshold between the shower and the rest of the bath. The floor slopes in one direction toward the channel, like a tipped tray. That single plane lets us use large-format tile, 12x24, 24x24, even 24x48 slabs, without lippage or weird cuts at the drain. For most curbless showers we build, the linear drain is the answer. It looks better, drains faster, and fits the modern aesthetic almost every client is after.

Where we still use point drains: smaller showers where a linear drain would be overkill, traditional or vintage baths in Tudor and Victorian homes where a round chrome drain reads more period-appropriate, or budget-driven jobs where the $400 to $900 premium for a quality linear drain matters. For the bulk of our work, though, linear wins.

Waterproofing system: Schluter-Kerdi vs RedGard (we use Schluter on every job)

There are two main waterproofing approaches for tile showers: a sheet membrane like Schluter-Kerdi, or a liquid-applied membrane like RedGard or Hydro Ban. Both can work. We use Schluter-Kerdi on every curbless shower we build, and we'll explain why.

Schluter-Kerdi is an orange polyethylene sheet that we adhere over the substrate with unmodified thinset. The seams overlap and get sealed with Kerdi-Band. The drain, corners, and pipe penetrations have purpose-built pieces (Kerdi-Drain, preformed corners, pipe seals) that integrate with the sheet. Once installed, the entire shower is a continuous waterproof envelope. We can flood-test it the next day and see immediately whether it holds.

RedGard is a paint-on liquid membrane. It's cheaper in materials, faster on small jobs, and a competent tile setter can do it well. The problem is consistency. Liquid membranes require a specific mil thickness (typically 30 to 60 wet mils) applied in two coats, and there's no easy way to verify the coverage was correct after it dries. We've been called in to fix curbless showers that failed at 18 months because the liquid was applied too thin in a corner or over a substrate seam.

On a curbless shower specifically, where there's no curb to backstop a waterproofing failure, the margin for error is zero. Schluter costs us more in materials and labor (roughly 15 to 25 percent more on the waterproofing scope), but the system is verifiable, repeatable, and warrantied by the manufacturer when installed by a certified installer. Every shower we build, curbless or curbed, gets Schluter. It's not the cheapest path, it's the right one.

Subfloor prep and slope (1/4" per foot minimum)

In an older Minneapolis or Saint Paul home, especially the 1920s bungalows and Tudors we work in constantly, the bathroom subfloor is almost never level enough or low enough to support a curbless shower without modification. We have two ways to build the slope.

On a slab-on-grade or basement remodel, we can sometimes pour a recessed mud bed directly into the slab. On a second-story bathroom in an old bungalow, we usually have to drop the joists or sister them down by 1.5 to 2 inches in the shower area so the finished tile sits flush with the rest of the bath. This is structural work. We pull permits, the framing gets inspected, and we coordinate with a structural engineer when a joist span is anywhere near its limit.

Code minimum slope to drain is 1/4 inch per foot. We'll often push to 5/16 or 3/8 per foot on larger showers because water moves faster, dries faster, and the shower stays cleaner long-term. The slope gets built into the mud bed, then Schluter goes over the top, then tile. By the time the tile is set, the slope is invisible to the eye but engineered for proper drainage.

Glass options: fixed panel, frameless enclosure, fully open wet-room

Glass is where curbless showers earn their visual reputation. The three main configurations:

Fixed glass panel (single panel, no door). A 3/8 or 1/2 inch tempered glass panel mounted to one wall, typically 36 to 60 inches wide, with a 24-inch open entry. This is our most-specified option. It blocks the main splash zone, lets light through, and skips the door hardware. Budget: roughly $1,200 to $2,500 installed depending on size and mounting.

Frameless hinged or sliding enclosure. A traditional shower enclosure but built with no curb beneath. The glass sits on the tile floor with a small gap and a sweep. This costs more, around $2,500 to $5,000, but gives you full splash containment if the shower is in a tight space or near a vanity.

Fully open wet-room.No glass at all. The entire bathroom is essentially the shower floor, waterproofed and sloped to a drain. We've done this in a handful of larger primary baths in Kenwood and on the Edina lakeshore. It's stunning, but it requires careful drain placement, ventilation, and a willingness to live with a wetter bathroom floor. Not for everyone.

Cost ranges: $12K to $35K in the Twin Cities by tile and glass spec

A curbless shower as a standalone project, demo to finish, runs $12,000 to $35,000 in our market. The spread is driven mostly by tile and glass. As part of a full bathroom remodel, the curbless shower is usually 30 to 45 percent of the total budget. For broader context on full bath budgets, see our Twin Cities bathroom remodel cost guide.

Variables that move the number: joist modification (add $2K to $5K if structural work is needed), heated floor extension into the shower (add $800 to $1,800), niche or bench (add $400 to $1,200 each), and tile labor. Slab porcelain and natural stone double or triple the install labor compared to standard porcelain. Our tile installation pricing scales with format, pattern, and substrate prep.

Heated tile floor pairs well (extending floor heat into the shower)

If you're putting a heated floor in the rest of the bathroom, and on a Minnesota winter morning you absolutely should, run the heat mat into the shower too. Schluter-Ditra-Heat and similar systems are rated for wet areas and integrate cleanly with the Kerdi waterproofing layer.

The benefit is bigger than just warm feet. A heated shower floor dries faster after use, which means less standing water, less mildew at grout lines, and a cleaner long-term result. On a curbless shower, where water can wick out beyond the slope line a bit, faster drying is a real maintenance win. Cost to extend heat into a typical shower footprint is $400 to $900 in materials plus install. Worth it on almost every job.

Aging-in-place benefits

A lot of our curbless installs in St. Paul and the southwest Minneapolis neighborhoods are driven by clients in their 50s and 60s planning their forever bathroom. The aging-in-place case is straightforward.

No curb means no trip hazard. A 36-inch wide entry (which a frameless or fixed-panel curbless easily accommodates) is wheelchair-accessible. A linear drain at the entry threshold catches splash without needing a step. Add a bench (built-in or fold-down), a hand-held shower head on a slide bar, and grab bars discreetly tiled into the wall blocking, and you have a shower that works at 45 and at 85. We build the blocking for grab bars on every aging-in-place job whether or not the client wants the bars installed today. Putting blocking in the wall during a remodel costs nothing. Adding it later means tearing tile out.

Pitfalls: bad waterproofing, undersized drain, splash zone

The three failures we see most often when we're called to fix someone else's curbless shower:

Waterproofing shortcuts. Skim coats of liquid membrane, no waterproofing at the drain flange, unsealed corners, or worst, tile set directly on cement board with no membrane at all. These fail in 12 to 36 months. Water gets into the joist bay and you find out when the kitchen ceiling below stains.

Undersized drain. A 2-inch point drain handles maybe 8 to 10 gallons per minute. A high-flow rain head plus a body spray can push 14+ gpm. The drain backs up, water pools, and on a curbless shower with no curb, that water leaves the shower. We spec linear drains by flow rate, not by what looks nice in the showroom.

Splash zone miscalculation. Open showers with no glass need the shower head positioned so the spray pattern is contained by the slope and a reasonable splash margin. A 6-foot ceiling-mounted rain head over a 36-inch shower pan with no glass is going to wet the entire bathroom. We model the splash zone on every open or partial-glass design before we frame.

When NOT to do curbless

We will tell a client to stick with a curbed shower in a few situations.

Basement showers. Below-grade bathrooms in old Minneapolis homes often have rough-plumbed drains at slab level with limited slope available. Building a curbless pan means either breaking concrete and re-plumbing, or building a raised platform that defeats the point. A traditional curbed pan with a low-profile threshold is often the smarter call.

Water table or sump issues.If the home has had basement water intrusion, a high water table, or sump pump activity, we're extra conservative with any below-grade waterproofing.

Second-story bathrooms over finished living space with limited joist room.If we can't safely modify the joists to recess the pan, we may build a very-low-curb hybrid (a 1-inch tile transition that's nearly flush) rather than fight a structural problem.

Tight powder-bath retrofits.A 30 square foot bathroom with a corner shower doesn't gain much from going curbless and loses splash containment.

FAQ

Does a curbless shower leak more than a curbed one?
Not when it's built correctly. The waterproofing system is the same envelope. The difference is that a curbed shower forgives small mistakes because the curb backstops them. A curbless shower has no backstop, so the install has to be right. With Schluter-Kerdi and a flood test, we have zero leaks across years of curbless installs.

Can you put a curbless shower in an old Tudor or bungalow second-floor bath?
Yes, most of the time. The joists usually need to be modified to recess the pan. We've done curbless installs in 1920s Tudors in Crocus Hill and Linden Hills bungalows where we sistered down the joists in the shower area to gain the depth. Pulled permits, structural sign-off, no issues.

Does water escape the shower onto the bathroom floor?
With proper slope and a correctly sized linear drain, no. The slope pulls water to the drain faster than it can travel outward. Splash from the shower head can land outside the shower, which is why we model the spray pattern and recommend at least a fixed glass panel on most installs.

How long does the build take?
A curbless shower adds 2 to 4 days to a typical bathroom remodel timeline versus a curbed shower, mostly in subfloor modification and waterproofing flood-test cure time. A full bath remodel with curbless runs 4 to 7 weeks start to finish in our shop.

Will it hurt resale value?
The opposite. In the $700K+ Twin Cities market we work in (Edina, Kenwood, Highland Park, Crocus Hill, North Oaks), a well-built curbless shower is now expected in the primary bath. It reads modern, accessible, and high-end. It's a positive at appraisal and in showings.

If you're planning a primary bath remodel and want to talk through whether curbless makes sense for your home, your subfloor, and your budget, get in touch. We'll walk the space, check the joists, and tell you honestly whether curbless is the right call or whether a low-curb hybrid would serve you better. If you're thinking bigger and the bath is part of a larger remodel, our kitchen and custom cabinetry teams work alongside the bath builds, and if you're speccing finishes, our countertop shop carries Cambria from Le Sueur for vanity tops that match the rest of the home. For broader budgeting, the kitchen remodel cost guide and quartz vs granite breakdown are good next reads.