Short Answer
A zero entry shower, also called a curbless shower, has no curb or step. The bathroom floor runs straight into the shower. To make it work, the shower floor is set lower than the rest of the room so water still slopes to the drain. On a Houston slab, that usually means cutting the concrete and moving the drain.
Repipe Solutions is a licensed Houston plumbing company that builds curbless zero-entry showers, low-threshold walk-ins, and custom tiled showers. This guide explains how a zero entry shower is built, what it takes on a concrete slab, how it keeps water off the bathroom floor, and what it costs.
What Is a Zero Entry Shower?
“Zero entry,” “curbless,” “zero threshold,” “barrier-free,” and “roll-in” all describe the same idea: a shower you can walk or roll into without stepping over anything. A standard shower has a curb, which Re-Bath puts at 3 to 6 inches tall. A low-threshold shower cuts that down to a small lip. A zero entry shower removes it completely.
Without a curb, the only thing keeping water in the shower is the floor itself. Every square inch has to fall toward the drain, and the drain has to sit low enough to receive it. That is why a zero entry shower is mostly a floor and drain project, with the tile and glass coming after.
Three Ways to Build a Curbless Shower
Schluter, one of the main makers of curbless shower systems, describes three ways to get rid of the curb:
| Method | How It Works | Best For |
|---|---|---|
| Recess the floor | The shower area is dropped below the bathroom floor, so the slope fits under finished floor height | A true flush entry with no ramp |
| Tray and ramp | A thin, pre-sloped tray sits on the floor with a gentle ramp at the entry | Floors that cannot be lowered |
| Raise the whole bathroom | The rest of the bathroom floor is built up to meet the top of the shower floor | Full remodels where door heights allow it |
Recessing gives the cleanest result, and it is the method most people picture. It is also the one that depends most on what is under your floor.
Can You Build a Zero Entry Shower on a Concrete Slab?
Yes, and many Greater Houston homes are built on one. A lot of national advice assumes a crawlspace or wood joists. Better Homes & Gardens quotes a designer who calls curbless showers best suited to homes with a crawlspace, since the drain and its trap need room below the floor. On a slab, there is no open space under the floor. The room for the trap has to be cut into the concrete.
On a slab, a curbless build usually looks like this:
- Saw-cut and break out the slab across the full shower footprint, not just a strip at the entry.
- Re-route or lower the drain line under the slab so the new drain and trap sit at the right depth and location.
- Repour the concrete lower than the surrounding floor to make room for the slope and the waterproofing.
- Pre-slope, waterproof, and tile once the concrete is ready.
The recess has to cover everywhere the spray lands, so water from any part of the shower runs to the drain instead of across a flat spot. DIYTileGuy notes that concrete floors need to be jackhammered for this kind of build, while wood floors may need a structural engineer to sign off on cutting joists.
At Repipe Solutions, slab drain relocation is a $1,500 to $3,500 add-on to the shower itself. Because the drain line runs under the slab, this is plumbing work first and tile work second. It also needs a permit, since the drain is being altered.
How Much Slope Does a Curbless Shower Need?
Plumbing codes set a minimum and maximum slope for any shower floor. The Texas edition of the 2021 International Residential Code calls for at least 1/4 inch of fall per foot and no more than 1/2 inch per foot. The Uniform Plumbing Code family, which the City of Houston follows, allows as little as 1/8 inch per foot.
In a curbed shower, a slope on the shallow side is forgiving, because the curb catches whatever does not reach the drain. In a curbless shower there is no backup, so the slope has to be right across the whole floor. That is the main reason these showers need careful layout before anything is poured.
Linear Drain or Center Drain?
| Linear Drain | Center Drain | |
|---|---|---|
| Floor slope | One direction | Four directions toward the middle |
| Tile | Works with large-format tile | Needs smaller tile to follow the slopes |
| Placement | Back wall, side wall, or across the entry | Middle of the floor, often under a rain head |
| Cost | Higher | Lower |
Ranney Blair and most curbless builders lean toward linear drains, because a single slope is easier to get right over a wide, open floor. Where the drain goes matters as much as the type. A drain at the back wall can take more water than one at the entry, and DIYTileGuy points out that with an entry drain, fast-moving water can run past it and onto the bathroom floor.
Whatever the style, the drain is sized by code. A shower needs a 2-inch drain, and that does not change because the grate is long and narrow.
Does Water Get on the Bathroom Floor?
Some can, and planning for it is part of the design. The UPC-based model code treats it seriously: under Section 408.6, when a shower has no threshold, the floor space in the same room is considered a wet location. That affects waterproofing, flooring, and even electrical outlets near the shower.
Ways to keep water where it belongs:
- Waterproof past the shower. Schluter recommends carrying the waterproofing at least one foot beyond the shower area. We use membrane waterproofing and mold-resistant backer board.
- Put the drain away from the entry so water runs away from the open side.
- Add a fixed glass panel. One stationary pane of glass next to the showerhead stops the worst of the splash, and there is no door to swing.
- Aim the showerhead away from the opening, or use a ceiling-mounted rain head.
- Choose slip-resistant tile for the shower and the floor around it. Look for a DCOF rating of 0.42 or higher.
If you are thinking about skipping glass entirely, our guide to doorless walk-in showers covers sizing and spray control in detail.
How Much Does a Zero Entry Shower Cost?
National sources disagree on how much more a curbless shower costs than one with a curb, and the spread comes almost entirely from the floor work.
| Source | What It Says About Curbless Cost |
|---|---|
| Fixr | About $6,000 average for a curbless or barrier-free walk-in, and usually not much more than a curbed one |
| Angi | $500 to $700 or more on top of a curbed walk-in |
| Ranney Blair | $2,000 or more over a curbed shower |
| DIYTileGuy | Budget at least 20% more than the same shower with a curb |
The low numbers fit a tray-and-ramp build or a home where the floor is easy to lower. The high numbers fit a recessed floor with a moved drain, which is the usual situation on a Houston slab. With Repipe Solutions, a custom tile shower runs $5,500 to $15,000 or more, with slab drain relocation at $1,500 to $3,500 when the layout needs it. For a broader look at walk-in pricing, see our walk-in shower cost guide.
Is a Zero Entry Shower Good for Aging in Place?
It is one of the most common aging-in-place upgrades. According to the CDC, more than one in four older adults falls each year, and falling once doubles the chance of falling again. Removing the step into the shower takes away one of the easiest places to trip. An AARP survey found 75% of adults 50 and older want to stay in their current homes as they age.
For anyone planning around a wheelchair, the 2010 ADA Standards are a useful benchmark even in a private home. A standard roll-in shower is at least 30 inches wide and 60 inches deep with a 60-inch-wide entry, and the threshold can be no more than 1/2 inch tall. A hand shower on a hose at least 59 inches long makes seated showering practical.
Plan the extras while the walls are open:
- Blocking for grab bars, so bars can go in now or later without hunting for studs.
- A fold-down bench that stays out of the way until it is needed.
- A scald-protected valve. Texas requires anti-scald protection on shower valves.
How Long Does It Take?
A curbless shower on a slab is a custom tile job with slab work, which takes 5 to 8 working days with Repipe Solutions. The concrete, waterproofing, thinset, and grout each need time to set before the next step. If you are starting from a bathtub rather than an old shower, our guide to tub to shower conversion ideas covers the other options.
Frequently Asked Questions
Is a zero entry shower the same as a curbless shower?
Yes. Zero entry, curbless, zero threshold, and barrier-free all mean a shower with no curb to step over.
Do curbless showers leak?
Not when the floor is sloped correctly and waterproofed past the shower. Most problems come from a shallow or uneven slope, a drain placed at the entry, or waterproofing that stops at the shower’s edge.
Do I need a glass door on a curbless shower?
No. Many curbless showers use one fixed glass panel, or no glass at all in a deep enough shower. A door with a sweep at the bottom does keep the most water in.
How big should a curbless shower be?
Bigger is easier, because water has more room to reach the drain before it reaches the entry. Ranney Blair suggests at least 5 feet by 5 feet, and the ADA roll-in minimum is 30 by 60 inches.
Can a curbless shower go upstairs?
Sometimes. On a second floor, the floor framing has to be lowered or the bathroom floor raised, and that depends on the joists. It needs to be checked in person.
Thinking About a Zero Entry Shower?
Repipe Solutions builds curbless zero-entry showers across Greater Houston, including the slab cutting, drain work, waterproofing, and permit. Quotes are free and in person with no trip charge. See our shower and bathtub services in Houston or contact Repipe Solutions to schedule a visit.
Featured photo: “Open tiled shower with floor drain” by juhansonin via Openverse, licensed under CC BY 2.0, converted to WebP.