When people plan a new bathroom, the conversation usually centres on what they’ll look at every morning: the tile, the vanity, the glass shower screen, the finish on the faucet. Those choices shape how a bathroom feels. Whether it still looks good in ten years depends on two things you will never see once the job is done: how the room handles water, and how it gets rid of moisture.
Bathrooms are the wettest rooms in any house. A single shower releases a surprising amount of water vapour, and in a Canadian winter, when windows stay shut and outdoor air is cold, that moisture has to go somewhere. If the room isn’t built to deal with it, it ends up in drywall, behind tile and inside wall cavities.
Tile is not waterproof
This surprises many homeowners. Ceramic and porcelain tiles shed water well, but grout is porous, and cement backer board, while it won’t rot, lets moisture pass through. Over time water works its way behind the tile, and if nothing stops it there, it reaches the framing.
Modern bathrooms deal with this using a dedicated waterproofing layer behind the tile, usually a bonded sheet membrane or a liquid-applied coating that covers walls, the shower floor and every seam, corner and pipe penetration. Systems such as Schluter’s are widely used by renovators because the membrane, drain and transitions are designed to work together. Ask any contractor which system they use, how they treat corners and niches, and whether the shower floor is sloped properly toward the drain before the membrane goes on.
Done right, this layer is the difference between a shower that lasts for decades and one that needs to be torn out after a handful of years because the subfloor has gone soft.
Ventilation: the fan matters more than you think
The second hidden system is the exhaust fan. In many older Toronto homes it is either missing, undersized or venting into the attic, which only moves the moisture problem somewhere you can’t see it.
The Home Ventilating Institute, which certifies fan performance in North America, recommends at least one cubic foot per minute (CFM) of airflow per square foot of floor area for a typical bathroom, with a minimum of 50 CFM. For bathrooms larger than 100 square feet, HVI suggests sizing by fixture instead: 50 CFM for each toilet, shower and bathtub, and 100 CFM for a jetted tub. A generous ensuite with a separate shower, freestanding tub and toilet would therefore need around 150 CFM, roughly three times what a builder-grade fan delivers.
A few other details make a real difference:
- Vent outdoors. The duct should carry air all the way outside, through a wall or roof cap, not into the attic or a soffit where it can condense and drip back down.
- Keep the duct short and smooth. Long runs and tight bends reduce airflow, so a fan rated at 80 CFM can perform like a much weaker one.
- Choose a quiet model. Fans with a low sone rating are more likely to be used. A loud fan is a fan that gets switched off.
- Add a timer or humidity sensor. Running the fan for a while after a shower clears moisture that lingers once the steam is gone.
What older homes add to the picture
A bathroom in a house built in the 1920s or 1950s often comes with its own complications. Original cast-iron drains and galvanized supply pipes may be nearing the end of their lives. Subfloors may have absorbed decades of small leaks. Walls may have been re-tiled several times over, each layer added on top of the last. A careful contractor will open things up, assess what’s there and recommend replacing what’s compromised rather than tiling over it.
This is also why bathroom timelines vary. A straightforward cosmetic update with the layout unchanged might take two to four weeks. A full renovation, with new plumbing, a moved shower or a reconfigured layout, more often runs six to ten weeks once permits and inspections are included.
Questions to ask before you sign
When comparing quotes for a bathroom renovation in Toronto, it’s worth looking past the fixtures list and asking how the invisible work will be done:
- Which waterproofing system will be used, and does it cover the full shower area, including the ceiling in steam showers?
- What size of exhaust fan is planned, and where will it vent?
- Will old drain and supply lines be replaced or reused?
- Is the shower floor sloped and tested before tile goes down?
- What does the warranty cover if a leak appears later?
A contractor who answers these clearly, and without hesitation, is likely to take the same care with the rest of the job.
Beauty that lasts
It’s easy to spend the bulk of a bathroom budget on the visible finishes and treat the hidden layers as an afterthought. The smarter approach is the reverse: get the waterproofing and ventilation right first, then choose finishes knowing they’ll be protected. The tile you love will only stay beautiful if the wall behind it stays dry.
