A curbless shower looks simple from the doorway: no lip to step over, one continuous floor running from the vanity into the wet zone. What makes it work is hidden under the tile: if the floor cannot catch water and carry it away, that water ends up under the vanity and out in the hallway. Below: what the floor needs, how to decide whether your bathroom can support it, the common mistakes, and where a pro earns their fee. Requirements vary by province and municipality across Canada, so treat this as orientation and confirm specifics with your local building department.
Why the floor does all the work
In a conventional shower, the curb is the dam. Remove it and three things take its place: a recess, so the shower floor sits below the surrounding floor; a slope that moves water to the drain before it spreads; and a waterproofing layer that assumes some water gets past the grout anyway.
The recess is what catches most homeowners off guard. On a wood-framed floor, creating it usually means lowering the subfloor between the joists or raising the rest of the bathroom floor to meet the shower. On a concrete slab, common in basements from the Prairies to the Maritimes and in condo towers from Vancouver to Montreal, it means cutting the slab or building the surrounding floor up.
The four things a curbless floor must have
| Requirement | What it does | Common ways to get there |
|---|---|---|
| Recess or drop | Keeps the shower floor below the entry | Lowered subfloor, cut slab, raised bathroom floor, low-profile preformed base |
| Slope to the drain | Moves water to the drain before it reaches the opening | Hand-pitched mortar bed, pre-sloped foam tray, factory-sloped base |
| Continuous waterproofing | Protects framing and rooms below from water that passes through grout | Bonded sheet or liquid membrane, carried past the shower zone and up the walls |
| A drain matched to the system | Lets water below the tile still exit | Point drain with bonding flange, or linear drain along a wall or at the entry |
Slope. Installers aim for a gentle, consistent pitch toward the drain: too little and water creeps toward the opening, too much and large tiles will not sit flat. Follow the drain and membrane manufacturers' instructions, because they are the ones warranting the assembly.
Drain. This decision shapes everything else. A point drain in the centre needs the floor pitched toward it from four directions, which is why those floors are almost always mosaic tile. A linear drain along the back wall or across the entry lets the whole floor fall in a single plane, so large-format tile becomes practical, and at the entry it doubles as a last line of defence. Whichever you choose, look for a drain listed for Canadian use (cUPC or CSA marks are the usual indicators) and designed to bond to your membrane.
Waterproofing. Grout is not waterproof and tile joints move. The membrane under the tile is what actually protects the framing and the ceiling below, and in a curbless shower it has to extend well past the shower footprint onto the bathroom floor and up the walls, because nothing physical stops water leaving the wet zone. Use one compatible system for membrane, drain flange and corners, and flood test before a single tile goes down.
A practical decision path
- Find out what is under the floor. Joist depth and direction on a framed floor; radiant heat and the existing drain run in a slab.
- Locate the drain and the entry. Water should travel away from the opening. Moving a drain on a framed floor is routine plumbing; moving it in a slab is a bigger, messier job.
- Pick the build method. Site-built mortar bed, pre-sloped foam kit, or a preformed curbless base. Bases from makers such as Maax and Kalia arrive pre-sloped but fix the drain position, so measure carefully.
- Choose the drain before you choose the tile. Linear drain with large-format tile, or point drain with mosaic. Mixing the two is where floors go wrong.
- Plan the glass and the shower head together. Point the head away from the opening and add a fixed panel where the room is tight.
- Talk to your municipality. Structural changes and drain relocations usually need a permit. Plumbing follows the National Plumbing Code as adopted by each province, and your local authority has the final word.
Mistakes that turn a curbless shower into a leak
- Tiling a flat floor and trusting the drain. Without a true recess and slope, the shower will flood the room.
- Stopping the membrane at the shower edge. The wet zone in a curbless bathroom is bigger than the shower. Waterproof accordingly.
- Skipping grab bar blocking. Many curbless showers are built for aging in place. Add blocking now, even if bars come later.
- Running heating cable under the drain. Electric in-floor heat is welcome in an Edmonton or Winnipeg winter and works under a curbless floor, but the element must stay clear of the drain body and suit the membrane.
When to call a pro
Demolition, tile and finishing are realistic for a handy homeowner. The parts that reward a professional are the ones you cannot easily undo: modifying joists or cutting a slab, relocating a drain, and installing the waterproofing. Membrane makers often tie warranties to trained installers, and a leak under a second-floor bathroom is expensive anywhere. In a condo or strata, check the bylaws first, because many buildings restrict changes to slabs and plumbing stacks. A good tile setter will also tell you honestly when curbless does not fit: a tiny bathroom with the door beside the shower, or shallow joists over a finished ceiling, sometimes calls for a low-profile base with a minimal threshold instead. That is the right answer for that room, not a failure.
Products that relate to a curbless build
- Shower bases. Preformed low-profile and curbless-ready bases in acrylic and composite. Browse the shower base collection to compare footprints.
- Drains. Linear and point drains in finishes that match your trim, including tile-in grates. See the drain collection.
- Glass and controls. Fixed panels and low-profile shower doors, plus thermostatic shower systems with hand showers on slide bars.
- Grab bars. Designer grab bars that read as towel bars. See grab bars.
Everything above ships across Canada and is priced in Canadian dollars. For more planning help, visit the Vatero guides hub, and if you build bathrooms for a living, see the Trade Program.
Frequently asked questions
Are curbless showers allowed under Canadian building codes?
Codes across Canada do not prohibit curbless showers. What they regulate is how the floor drains and is waterproofed and, in accessible units, clearances. Requirements flow from the National Building Code and National Plumbing Code as adopted by each province and municipality, so get a permit and let the inspector confirm the details.
Can I build a curbless shower on a concrete slab?
Yes. The recess comes from cutting and chipping the slab, common in basement bathrooms, or from building up the surrounding floor. Moving a drain in a slab is real work, so design around the existing location if you can.
Linear drain or point drain: which is better for curbless?
Linear drains are the more forgiving choice: single-plane slope, large tile, and at the entry they catch water heading for the door. Point drains suit a mosaic floor but need four-way slope and more depth. Either works when the slope and membrane are done properly.
Will water really stay in the shower without a curb?
It will if the floor is recessed and sloped, the glass is positioned sensibly and the shower head points away from the opening. Larger showers keep water in more easily. If your room is tight, a linear drain at the entry and a fixed glass panel go a long way.
