A tiled shower does not fail at the tile. It fails behind it, and by the time anyone can see the failure the wall behind the tile has been wet for a season. This guide is about the part of a tiled shower you can never inspect once it is finished, which makes it the part worth understanding before you buy one.
Tile is not the waterproofing
Start here, because most homeowners assume the opposite. Ceramic and porcelain tile are close to impermeable in the body, but a tiled surface is not: the grout joints are porous, and there are a lot of them. Water moves through grout continuously during a shower. That is normal and it is designed for.
What is supposed to happen is that the water reaches a membrane behind the tile, runs down it, and drains out through the weep holes in the drain assembly. What actually happens in a badly built shower is that it reaches backer board, then framing.
Sealing grout every year is worth doing for staining. It does nothing for waterproofing.
The two systems, and how to tell them apart
Bonded membrane over the board. A sheet or liquid membrane applied on top of the backer board, taken continuously through the corners, over the curb and into the niche, then bonded to the tile. Water never reaches the board at all. This is what Barrie Bathrooms builds, and the product and manufacturer go on the quote so you can read the installation detail yourself.
Vapour sheet behind the board, pan liner in the floor. The older approach: polyethylene stapled to the studs, cement board over it, and a lead or PVC liner forming the floor pan. It works, and there are thirty-year-old showers in Barrie built this way that are still dry. It is less forgiving, because the waterproofing sits behind the board rather than in front of it, so any water passing the grout is already inside the wall assembly before the system sees it. The curb detail is where it most often goes wrong.
The two are not equivalent and they should not cost the same. Neither of them is visible in a finished shower, which is exactly why it has to be settled on paper.
The five details that decide whether it lasts
- Slope set in the base, not in the tile. Water finds level. A base sloped by pressing tile harder at the drain is a base that ponds, and standing water sits on the grout permanently rather than for three minutes.
- The membrane continuous through every internal corner, using the manufacturer’s own preformed corners rather than a folded offcut. Corners move. A cut-and-lapped corner is a hinge.
- The niche sloped forward and waterproofed as its own small shower. A flat niche is a shelf that holds water behind a bead of silicone. It is the most common leak point in showers built in the last decade, because niches became fashionable faster than the detail spread.
- Silicone, not grout, in every change-of-plane joint — wall to wall, wall to floor, and around the curb. Grout is rigid, those joints move, and a cracked corner joint is a direct path into the wall cavity.
- Movement joints in a large tiled floor. A tile assembly over a wood subfloor moves seasonally, and the swing between a February heating season and an August humidity load in this climate is large. The joints go where the tile industry details put them, or a hairline crack appears in year two.
What the local conditions add
Two things matter more here than they do further south.
Ventilation. A shower enclosure in a snow-belt climate has to dry between uses, and it dries by being ventilated. A fan that is undersized, ducted with uninsulated flex, or terminating at a soffit does not do that — see why Barrie bathroom fans wreck attics. A shower that never fully dries grows mould at the silicone joints regardless of how well it was waterproofed.
Hard water. On a private well in Springwater, Minesing or rural New Tecumseth, mineral content is high enough to etch honed natural stone and permanently fog untreated glass. That does not cause leaks, but it decides what you should specify: polished porcelain on the walls rather than honed stone, and coated glass rather than bare. The detail is in hard water will fog your new shower glass.
Reading the quote
Three questions, and they are short.
- Which membrane system, by name? You want a manufacturer and a product. Then look up the installation detail for corners, curbs and niches, and ask whether the quote includes the manufacturer’s own corner pieces.
- Is the slope in the base or in the tile? There is only one right answer.
- Silicone or grout in the corners? There is only one right answer to this as well, and a surprising number of quotes get it wrong.
A company that answers those three clearly is describing work it intends to do properly. A company that treats them as fussy detail is telling you something useful too.
For where the rest of the money goes on a bathroom renovation, see what a bathroom renovation costs in Barrie.