Bathroom remodeling: waterproofing, layout and cost

Tile isn't waterproof

Water gets through grout. It always has. Grout fills the joints between tiles, but it doesn't seal them, and a shower that relies on it will eventually soak the framing behind it. The waterproofing is a separate layer that goes on before any tile, and it's the thing in a bathroom quote you most need to have described in detail.

Where showers leak

• Corners and seams. Walls and floors move a little, and a membrane that isn't reinforced at the joints will split there first.
• The curb. It has three exposed sides and gets stepped on every day, so it needs to be wrapped on the top and both sides.
• Anything that goes through the membrane. The valve, the shower arm, a niche, a bench and the drain each need their own sealed detail.
• The slope under the membrane. The surface under the membrane has to fall toward the drain, usually a quarter inch per foot, so water that reaches it can drain away. If the slope is only built into the tile, water gets trapped underneath.
• The edge of the shower. Where the wet floor meets the rest of the room is another joint, and joints leak.

Shower leaks are slow and quiet. By the time a stain shows up on the ceiling below, water has usually been in the floor for months. Pay for the waterproofing properly once instead of saving a little and rebuilding in six years.

Questions to ask the installer

1. 1.

   Which membrane will you use?

   You want a product name and a method, not "we waterproof it." An installer who can name both has done this before.

2. 2.

   How will you build the slope to the drain?

   A mortar bed or a pre-formed pan, and where the low point is. This question tells a tile setter apart from someone who builds showers.

3. 3.

   Is any drain moving?

   Confirm this before pricing. It's the difference between finish work and opening up the floor.

4. 4.

   What size fan, and where does it vent?

   It should be sized for the room and ducted outside. It should never vent into the attic or the soffit.

5. 5.

   Will you flood-test the pan before tiling?

   A flood test holds water in the shower pan for 24 hours before any tile goes down. It's cheap and quick, and it's the only chance to find a leak while it's still easy to fix.

The clearances that decide your layout

Most bathrooms are small, and every fixture needs a certain amount of space around it. Those clearances usually decide whether a layout works, more than your taste does.

In a tight room, the cheapest ways to gain space usually aren't structural. A pocket door or an outswing door gets back the whole swing. A wall-hung vanity and toilet leave the floor open and make cleaning easier. A glass screen instead of a curtain keeps the room feeling bigger. None of these moves a drain, so they stay affordable.

What drives the cost

The biggest single decision is whether any drains move. Replacing fixtures in their current spots is finish work. Moving the toilet drain means opening the floor, re-cutting the slope and re-venting, and in a condo or on a slab it can be off the table entirely.

Quick answers