How to tile a floor: a step-by-step guide

1. Measure and order tiles

Measure the floor and split L-shaped or irregular rooms into rectangles. Add 10% for cuts and breakage on a straight layout, and 15% for diagonal or herringbone patterns. The Tile calculator works out the number of tiles and boxes, including the grout joint.

Buy every box from the same production batch (shade or lot number printed on the box) and keep a few spare tiles for future repairs. You will also need adhesive and grout; the Mortar calculator helps with mortar for a screed or bedding layer.

2. Check and prepare the subfloor

Tiles are rigid, so the surface under them must be solid, clean, dry and flat. Remove old flooring, loose paint and dust. Check flatness with a long straightedge: for large tiles (any side 38 cm or more), the industry guideline is no more than about 3 mm of deviation over 3 m. Fill dips with a self-leveling compound and grind down high spots.

A wooden subfloor that flexes underfoot will crack tiles and grout. Stiffen it, or install a cement backer board or uncoupling membrane following the manufacturer’s fastening schedule. Prime absorbent surfaces so the adhesive does not dry out too fast.

3. Plan the layout

Do not start in a corner: walls are rarely straight or square. Snap two perpendicular lines through the middle of the room and dry-lay a row of tiles with spacers along each line. Shift the lines so that the cut pieces at opposite walls are equal and no narrower than half a tile. In the most visible area, such as the doorway, aim for full tiles.

Plan to work toward the door so you never have to step on fresh tiles.

4. Mix and spread the adhesive

Use a cement-based tile adhesive (thinset) suited to the tile type; porcelain and large tiles need an improved, polymer-modified adhesive. Mix it with a paddle at low speed to the consistency on the bag, let it rest a few minutes, then mix briefly again. Mix only what you can use within its working time.

Spread the adhesive with the flat side of a notched trowel, then comb it with the notched side in straight, parallel lines. The notch size grows with tile size, roughly 6 mm for small tiles and 10–12 mm for large ones. Cover only about 1 m² at a time so the surface does not skin over.

5. Set the tiles

For tiles larger than about 30 cm, also spread a thin layer on the back of the tile (back-buttering). Place each tile slightly off its final position and slide it across the ridges to collapse them, then press it down. Insert spacers so the joints stay even.

Every so often, lift a freshly laid tile to check the back. The adhesive should cover at least 80% of the back in dry areas and 95% in bathrooms, showers and outdoors. Bare patches mean hollow spots that crack under load. Check the surface with a level and make sure neighboring edges are flush.

Clean adhesive out of the joints and off the tile faces before it hardens.

6. Cut the edge tiles

Measure each edge piece separately, deducting the joint width and a gap of about 5 mm at the wall for movement. A manual tile cutter gives clean straight cuts; for notches around pipes and door frames use an angle grinder with a diamond blade or tile nippers. Wear eye protection, and cut porcelain wet or outdoors because the dust contains silica.

7. Let the adhesive set

Do not walk on the floor until the adhesive has set, usually at least 24 hours, and longer in cold or damp rooms. Remove the spacers before grouting if the manufacturer says so.

8. Grout the joints

Mix grout to a smooth, paste-like consistency. Press it diagonally across the joints with a rubber float so the joints fill completely, then remove the excess with the edge of the float held almost upright.

When the grout has firmed slightly, typically after 10–30 minutes, wipe diagonally with a damp, well-wrung sponge, rinsing it often. Do not use too much water: it weakens the grout and causes color differences. Polish off the remaining haze with a dry cloth once the surface has dried.

Use a flexible sealant instead of grout along walls, at changes of plane and over movement joints, because these are the places where the floor moves.

9. Finish and protect

Let the grout cure as the manufacturer recommends before heavy use and before washing the floor. Cement-based grout in kitchens and bathrooms benefits from a penetrating sealer once fully cured. Refit the skirting boards over the perimeter gap.

Common mistakes

• Tiling over a floor that flexes or is out of flat, which leads to cracked tiles and grout.
• Using too small a trowel notch, which leaves hollow spots under large tiles.
• Starting the layout against a wall, which leaves thin slivers along the opposite wall.
• Spreading adhesive over too large an area, so that it skins over before the tiles are set.
• Grouting tight against walls instead of leaving a gap for a flexible sealant.

Frequently asked questions

Sources

• Ceramic Tile Foundation — Do You Have Enough Mortar to Accommodate Tile Warpage?
• Tile Council of North America (TCNA)
• Wikipedia — Tile