Tub to shower conversion

Taking out a tub and putting in a walk-in shower is the most requested single change in an Ottawa bathroom, and most of the cost sits in two places people do not expect: the drain and the floor build-up.

Step one: the drain position. A tub drain sits at one end of the tub. A shower drain usually sits in the middle of the floor area, or along one edge in a linear arrangement. Moving it means opening the floor and altering the drain piping, which is an alteration to a plumbing system and therefore permit work in Ottawa, since the exemption covers only replacing existing fixtures (City of Ottawa, Do I need a building permit). It is also the difference between a straightforward week of work and a job that depends on what direction your floor joists run.

Step two: joist direction, which decides feasibility. If the joists run perpendicular to the drain's new path, the new pipe has to cross them, and in a conventional 2 by 8 or 2 by 10 floor there is limited depth to get the fall a drain needs without notching a joist in a way that weakens it. Sometimes the answer is a linear drain against the wall where the plumbing already is. Sometimes it is a pre-formed pan with the drain where the tub drain was. Sometimes it is dropping the ceiling below, which is easy in a basement and unwelcome on a second floor. A good contractor looks at the joists before pricing the shower.

Step three: curbless, or not. A curbless entry needs the finished shower floor below the bathroom floor, which means recessing the joists or raising the room. On a second storey that is structural work and often needs an engineer. A low 50 to 75 millimetre curb gives most of the benefit for a fraction of the cost.

Step four: waterproofing. A shower gets water on it every day for twenty years and a tub surround does not, so the waterproofing standard goes up. The Code floor is that tile around a tub or shower be applied over moisture resistant backing (OBC 9.29.10.4, Moisture Resistant Backing) and that the joint between tile and tub or shower be caulked with a material conforming to CAN/CGSB-19.22-M (OBC 9.29.10.5, Joints between Tiles and Bathtub). Good practice is well beyond that: a continuous sheet or liquid-applied membrane, a bonded or pre-formed sloped pan, membrane properly treated at the corners and the drain, and a flood test held for 24 hours before tiling. Niches, benches and curbless entries are where failures start, so they need particular care.

Step five: fittings and glass. A mixing valve rated for the flow, and then glass. Frameless glass is measured after tiling and carries a lead time. Framed enclosures are quicker and cheaper.

How long it takes. One to two weeks of working time where the drain does not move and the layout stays put. Two to three weeks where the drain relocates, plus the permit and inspection schedule. Add one to three weeks of calendar time for custom glass at the end.

What it costs in Ottawa in 2026. Indicative. A tub removed and replaced with a pre-formed acrylic base and a tiled surround, drain unchanged, commonly runs $7,000 to $12,000. A fully tiled walk-in shower with a sloped mortar pan and a frameless glass panel is usually $12,000 to $22,000. A curbless shower with the floor structure modified is $18,000 to $35,000 and sometimes carries an engineer's fee. What moves the number: whether the drain moves, joist direction, tile format, whether the shower is over a basement or a finished room, and the glass specification.

What makes an Ottawa bathroom different. Age of stock and exterior walls. A great many Ottawa bathrooms have one wall on the building exterior, and in houses built before roughly 1980 that wall often has poor or no vapour control behind the tile. A shower on an exterior wall in this climate drives warm moist air into a cold cavity, and the result is mould behind sound-looking tile. Doing the vapour and air barrier properly while the wall is open is cheap and invisible, and it is skipped constantly. The other factor is the 1.5 metre steel tub set in mortar, standard in 1950s and 1960s Ottawa bungalows: these do not lift out, they come out in pieces, and the mortar bed beneath often took the last leak, so the subfloor underneath needs inspecting rather than covering.

Which credentials are required. Any alteration to the drain or supply piping is plumbing work, and plumber is a compulsory trade in Ontario under trade code 306A, requiring a Registered Training Agreement, a Provisional Certificate of Qualification or a Certificate of Qualification, checkable on the Skilled Trades Ontario public register (Skilled Trades Ontario, Plumber, trade code 306A). Tiling and waterproofing are not licensed trades in Ontario, so ask instead which membrane system is being used, whether the installer is trained on that specific system, and whether the manufacturer's warranty requires a certified installer, because several do. Liability insurance and WSIB coverage apply to everyone on site (WSIB, Expanded Compulsory Coverage in Construction).

What to ask before you hire. Does the drain move, and which way do my joists run. Permit or no permit, and who applies. Pre-formed pan or mortar bed, and why for this room. Which waterproofing membrane, and will you flood test it. Is there a vapour and air barrier going back on the exterior wall. Is the glass framed, semi-frameless or frameless, and when is it measured. Do you warrant the shower against leaks, for how long, and what voids that.