Measuring three walls and a pan
Take each wall on its own. A common 36 by 60 inch alcove shower has a 60 inch back wall and two 36 inch end walls. Tiled to 84 inches that is 60 x 84 plus two lots of 36 x 84, which is 5,040 plus 6,048 square inches — 77 square feet.
The pan is width times depth: 36 x 60 is 15 square feet. Add the curb. A curb is three surfaces — the top, the outside face and the inside face — each about 60 inches long and 4 to 6 inches wide, so roughly 6 square feet in total.
That is 98 square feet before waste. At 15% — small cuts, lots of edges, usually a first attempt — you are ordering 113 square feet, and the wall tile and floor tile are two separate orders. Put the wall runs into the subway tile calculator to get the box count and the grout for the field, and run the pan separately because mosaic coverage is different.
| Shower size | Walls | Pan | Curb | Niche | Total + 15% |
|---|---|---|---|---|---|
| 32 x 32 in corner | 37 sq ft | 7 sq ft | 3 sq ft | 3 sq ft | 58 sq ft |
| 36 x 36 in corner | 42 sq ft | 9 sq ft | 4 sq ft | 3 sq ft | 67 sq ft |
| 48 x 36 in alcove | 70 sq ft | 12 sq ft | 5 sq ft | 3 sq ft | 104 sq ft |
| 60 x 32 in alcove | 73 sq ft | 13 sq ft | 6 sq ft | 3 sq ft | 110 sq ft |
| 60 x 36 in alcove | 77 sq ft | 15 sq ft | 6 sq ft | 3 sq ft | 116 sq ft |
Two notes on that table. The wall figure assumes tiling to 84 inches; going to the ceiling at 96 inches adds roughly 15% to the wall number. And the pan figure is mosaic, which is bought and priced separately from the field tile — do not merge the two lines when you order.
The niche
A recessed niche is the detail that separates a considered shower from a builder-grade one, and it is where most DIY showers go wrong dimensionally.
Size the opening to whole tiles. If your field tile is 3 by 6 with a 1/16 inch joint, a niche 12 3/16 inches wide takes exactly four tiles across with no cut. Get this wrong and you have four slivers framing the most closely inspected 2 square feet of the bathroom.
Three more rules for niches:
- Put it on a dry wall — never on the wall with the plumbing, and never on an exterior wall in a cold climate, where the reduced insulation depth will cause condensation behind the tile.
- Slope the shelf forward by about 1/8 inch per foot so water drains out rather than sitting behind the shampoo.
- Waterproof it completely before tiling. A niche is a hole in your waterproofing and it must be sealed as a five-sided box.
Height matters as much as width. Set the bottom of the niche between 42 and 48 inches off the pan: high enough to reach without bending, low enough that a tall bottle does not hit the shelf above. If you are fitting two, keep them on the same centre line so the grout lines run through both.
Curb and threshold
The curb takes more cuts per square foot than anything else in the room. Three faces, four corners, and the top should ideally be a single piece of stone or a full tile so there is no grout joint sitting in standing water.
Slope the top of the curb back into the shower by about 1/4 inch. A flat curb top holds water against the door seal; a curb sloped outward sends it onto the bathroom floor.
If you are using a glass door, ask the glass company for their tolerance before you tile. Most want the curb within 1/4 inch of level across its length, and a curb tiled to the wrong dimension is a $600 problem when the glass arrives. Ask them for the hinge positions too: drilling a hinge hole through a tile after it is set is possible but nobody enjoys it.
Waterproofing before tile
Tile is not waterproof. Grout is not waterproof. What keeps water out of your framing is the membrane behind the tile, and there are only three acceptable answers.
| System | What it is | Cost per shower |
|---|---|---|
| Foam board | Kerdi-Board, Wedi and similar, sealed at the seams | $500 to $900 |
| Sheet membrane over backer | Cement board plus a bonded sheet membrane | $300 to $500 |
| Liquid membrane over backer | Cement board plus two coats of a rolled-on membrane | $200 to $350 |
What does not work: drywall, green board, cement board with nothing over it, and any of the above with an unsealed penetration for the mixing valve. Flood-test the pan for 24 hours before a single tile goes on. Finding a leak then costs an afternoon; finding it later costs the whole bathroom.
Do not mix systems. A liquid membrane rolled over a sheet membrane does not bond, and a foam board system sealed with the wrong brand of band voids the warranty on both. Pick one manufacturer's system and use its own corners, bands and sealant.
Slope and drain
The pan slopes to the drain at 1/4 inch per foot. In a 36 by 60 shower with a centre drain that is about 3/8 inch of fall from the wall to the drain — not much, but it must be consistent and it must be built into the mortar bed, not created with thinset under the tile.
Because the pan slopes and the walls do not, never start the wall tile off the pan. Screw a level ledger board one full tile height above the highest point of the pan, tile the field from there, then remove the ledger and cut the bottom row to follow the slope. That bottom row will be a tapered cut across the width of the shower, and that is correct.
Linear drains change this: they let the pan slope in one direction only, which means you can use large format tile on the floor instead of mosaic. They cost $200 to $500 more and they simplify the tiling considerably — on a large shower it is often the cheaper decision once you count the labour.
For the wall layout itself — where to put the centre line, how to balance the cuts at the corners — the method is the same as a floor and it is set out in how to lay out a tile floor. For choosing the tile body itself in a wet area, porcelain vs ceramic tile explains why absorption matters here more than anywhere else in the house.
Frequently asked questions
How much tile do I need for a standard shower?
A 3 by 5 foot shower tiled to 7 feet has about 78 square feet of wall, 15 square feet of pan, plus the curb and the niche. With 15% waste that is about 107 square feet.
Do I tile the shower floor with the same tile?
No. A shower pan needs small tile — 2 inch mosaic or smaller — so the grout joints provide grip and the sheet can follow the slope to the drain. Large tile cannot bend to the slope.
What goes behind shower tile?
A waterproof assembly: a foam board like Kerdi or Wedi, or cement board with a liquid membrane over it. Plain drywall, green board and cement board with no membrane all fail eventually.
How much thinset and grout does a shower take?
A standard 36 by 60 in alcove is about 98 square feet of tile, so two 50 lb bags of thinset for the walls with a 1/4 in trowel, plus a third bag for the mosaic pan. Grout runs 25 to 35 lb because the pan mosaic has so much joint per square foot.