A tub to shower conversion is the most common bathroom job we do for people who have stopped using the tub. It is not a fixture swap. Here is the sequence.

The tub comes out.

With it goes the surround and, usually, some of the wall board behind it. That is the first honest look anyone has had at what is behind your tile, and it is where surprises live.

The drain moves and the floor gets re-sloped.

A tub empties at one end through a trap under the floor; a shower empties from the middle of a sloped base. Relocating that connection and building the slope correctly is most of the labour, and it decides whether the finished shower holds water where it should.

The base.

A low-threshold base, or a fully curbless one where the floor framing allows it. Curbless needs the plumbing and the joists to co-operate, so we tell you on the first visit whether your floor can take it.

Waterproofing behind the tile.

The homeowner's guide on this page says it and it is worth saying twice: the membraned, sloped, properly detailed layer behind the tile is what makes a shower last. A conversion removes the one fixture that was containing the water, which raises the stakes on that invisible layer.

Glass or a curtain, and blocking in the walls.

Framed, frameless or a fixed panel; a curtain is cheaper and easier to live with when somebody needs a chair or a helper in there. While the wall is open we fix solid blocking behind the board where grab bars will go, even if no bars are going in yet. Almost nothing now, a wall demolition later.

Building in the tub's footprint keeps the bill down.

The same rule the guide gives for a full renovation applies here: staying in the existing footprint avoids moving supply and waste through joists, which is where the money and the permits go. A bathtub replacement and a tub to walk in shower conversion in the same footprint cost far more alike than people expect, so the choice is about how you want to use the room. If the tub is still the right call, a straight bathtub replacement is the shorter job.

We quote walk-in shower installation in writing after we have seen the room: the floor and what is behind the tile decide the number.

Most of the accessible bathroom renovation work we do is not for somebody in a wheelchair. It is for a parent who has decided they are not moving, and a family who would rather spend the money on the bathroom than on the alternative. Built at the same time as a renovation you were going to do anyway, almost none of it reads as medical.

What goes in:

• A curbless or low-threshold shower, so there is nothing to step over.
• Grab bars fixed into solid blocking in the wall. Bars screwed into tile and board will come off the wall with somebody's weight on them, which is worse than having none.
• A handheld shower on a slide bar, so it works seated or standing.
• A bench, folding or built in.
• Slip-resistant tile, in a size that keeps enough grout lines underfoot for grip.
• A wider door, and a swing that does not trap anyone behind it.
• A comfort-height toilet.
• Lever hardware instead of round knobs, which matters for arthritic hands.

Tub conversions for seniors are usually the centre of it. The tub wall is the single hardest thing in the room to get over, and removing it changes the room more than everything else on that list put together.

There may be a federal credit in play.

The Home Accessibility Tax Credit is non-refundable and may apply if you are 65 or older at the end of the year, or eligible for the disability tax credit. It covers up to $20,000 of eligible renovation expenses in a year. What counts as an eligible expense is the CRA's definition, not ours, and so is the amount of the credit itself, so read it there before you budget around it: line 31285, home accessibility expenses. Keep your invoices. The credit is claimed on your return, not by us.

If you are already planning a bathroom renovation in Toronto, this is the cheap moment to build the room for the next twenty years rather than the next five.