How to lay a tile floor: levels, set-out and spacing

A good tile floor is mostly won before the first tile goes down. Getting the levels, the set-out (layout) and the spacing right is what makes a floor look straight and stay bonded. This guide walks through how to lay a tile floor step by step, for tilers and handy tradies in any country.

Check the floor first

Tiles can only be as flat and solid as what is under them.

• Check the floor is clean, dry, solid and free of dust, paint and old adhesive
• Check flatness with a long straight edge. Mark the high and low spots
• Grind high spots and fill low spots with a levelling compound the adhesive maker allows
• Make sure timber floors are stiff enough for tiles, and use the right underlay or backer board
• In wet areas, the waterproofing must be done and cured first

Our guide to preparing a substrate for tiling covers this in detail.

Plan the set-out

The set-out decides where the tiles and cuts land. A bad set-out leaves thin slivers at the doorway, where everyone looks.

• Find the centre of the room by measuring each wall and snapping chalk lines between the middles
• Check the lines are square to each other using the 3, 4, 5 method: measure 3 units along one line and 4 along the other. The diagonal between those marks should be exactly 5
• Dry-lay a row of tiles with spacers along each line, from the centre to the walls
• If the last tile at a wall is less than half a tile, move the centre line by half a tile, so both sides get bigger cuts
• Put full tiles, or even cuts, at the doorway and the most visible wall. Hide the small cuts under cabinets or behind the toilet
• In a bathroom, line up the tiles with the shower waste or floor drain where you can

Mark your lines clearly. They are your guide for the whole floor.

Choose the joint width

The gap between tiles (the grout joint) is not just for looks. It takes up small size differences between tiles and allows a little movement.

• Rectified tiles, which have very straight machine-cut edges, can usually take narrow joints
• Non-rectified tiles need wider joints to hide size differences
• Follow the tile maker’s and grout maker’s advice for the minimum joint
• Leave a movement gap at walls and other fixed edges, and put movement joints where your local standard or the adhesive maker says. Don’t grout them solid

Mix and spread the adhesive

• Use an adhesive that suits the tile size, the tile type and the substrate. Large tiles and heated floors often need a flexible adhesive
• Mix it to the maker’s instructions and use it within its working time
• Spread only as much as you can tile before it skins over
• Use the notch size the data sheet recommends. Comb in straight lines, all in one direction
• For large tiles, also butter the back of each tile, so there are no hollow spots

Lift a tile now and then to check the coverage on the back. You want full, even contact, especially in wet areas and under heavy traffic.

Lay the tiles

1. Start where your lines cross, and work back towards the door so you don’t tile yourself in.
2. Press each tile down with a slight twist, then use spacers.
3. Check the level and line every few tiles with a straight edge and spirit level.
4. Watch for lippage, where one tile edge sits higher than the next. Levelling clips help a lot with large tiles.
5. Clean adhesive out of the joints before it sets.
6. Do the cut tiles last, measuring each one, as walls are rarely straight.
7. Keep foot traffic off the floor until the adhesive has set.

Grout and finish

• Wait for the adhesive to cure for the time on the data sheet before grouting
• Pack the grout firmly into the joints with a rubber float, working diagonally across the tiles
• Clean off the haze with a damp sponge, rinsing often
• Fill movement joints and the joint at the wall with a flexible sealant, not grout
• Seal the grout if the product needs it

For ordering amounts, see how to work out tile, adhesive and grout quantities. Metric first: work in square metres, and US readers can multiply by about 10.76 to get square feet.

A simple example

A bathroom floor is 2.5 by 1.9 metres, using 600 by 300 mm tiles laid lengthways. The tiler marks the centre lines and dry-lays a row along the 2.5 metre length. With a joint on the centre line, each end finishes with a cut of only 50 mm (about 2 inches). So she moves the line by half a tile, 300 mm. Now both ends get a 350 mm cut, which looks much better and is easier to fix. She lines the joints up with the floor waste and uses levelling clips to stop lippage.

Plan the room first with the free Bathroom Planner, which also shows the floor tile area for your layout.

Quick checklist

• Floor clean, dry, solid and flat
• Waterproofing done and cured in wet areas
• Centre lines snapped and checked square with 3, 4, 5
• Dry-laid, with no thin cuts at the doorway
• Joint width to the tile maker’s advice
• Right adhesive, right notch, full coverage
• Level and lippage checked as you go
• Movement joints left open and sealed, not grouted