Layout & Waste

Set out from the centre, never from a wall. No wall in a house is straight and no room is square, and both errors accumulate across the floor and arrive at the far wall as a visibly tapering course.

The method

Mark the room centre, snap two chalk lines at right angles through it, dry-lay a row along each line to the walls with spacers, and look at what lands at each wall. That fourth step is the whole point, and it is the one people skip.

The sliver rule

If the dry lay leaves a cut narrower than half a tile at a wall, shift the whole layout by half a tile. Narrow slivers are fragile, hard to bed, and they draw the eye — they are the main thing separating a professional-looking floor from an amateur one, and the fix costs ten minutes with a chalk line.

Aim for equal cuts at opposite walls in both axes. Where perfect balance is impossible, put full tiles where the eye lands first — the doorway, the vanity wall, the visible edge of an island — and put the compromise under cabinets or behind a door swing.

In bathrooms and kitchens the layout often reads off a focal point (the shower, the island) rather than the room centre.

Offset, for large format

A 50% offset puts the end of one plank against the middle of its neighbour — and long planks have a slight lengthwise crown from firing, so that is the highest point against the lowest.

Manufacturers now specify 33% offset or less for tile over 15 inches, and many warranties are void at 50%. Check the box before choosing a pattern.

Flatness, for large format

ANSI A108.02 requires 1/8 in in 10 ft, and 1/16 in in 2 ft for tile with any side over 15 inches. That is flatter than a typical subfloor, and meeting it usually means self-levelling compound before any tile is opened.

Levelling clips handle the residual. They cannot fix a substrate — over an uneven floor they produce a floor that is level at every joint and visibly wavy across the room.

Grout joint width

Non-rectified tiles need 1/8 in or more, because the joint absorbs the size variation between tiles. Rectified tiles are ground square after firing and can take 1/16 in. Sanded grout above 1/8, unsanded below.