Flatness, in figures
A substrate is checked with a 2 m straightedge laid on the floor, in several directions. The hollow it reveals is what the tile will have to bridge: the larger the format, the less able it is to do so. A 60 cm plank still follows a slight movement in the substrate; a 120 cm slab does not — it sits proud at the corner, and that is called lippage. You feel it underfoot before you see it.
That is why we apply the levelling compound beforehand, not as the work goes along. A levelling compound is poured, left to dry for as long as its maker states, then primed. That time is not negotiable: adhesive applied to a substrate that is still damp does not grip, and the tile sounds hollow a few months later, when nothing can be put right without taking the whole floor up again.
On large formats we double up the bedding — the adhesive is combed onto the floor and onto the back of the tile — so that there is no void under the slab. A void under a large format is the point where it will crack the day a heavy piece of furniture is set on it.
The setting out: where the first slab starts
Starting from a wall means leaving chance to decide the cut that will be left at the other end. And in a room, not all the corners are equal: the one you see from the door, the one that catches the raking light from the window, the one the eye stops at from the sofa. Setting out means deciding before laying where the cuts fall, and sending them where nobody looks.
Three simple rules guide that layout. Avoid the sliver of a cut: a three-centimetre strip along a wall shows and breaks. Line the joints up on the fixed points of the room — the centre of a door, the line of a kitchen unit, a stair nosing. And lay with the light, because a joint caught in raking light reads twice as strongly as the same joint seen head-on.
In Nice the light is unforgiving. A south-facing window at the end of the day reveals everything: an uneven joint, half a millimetre of lippage, a layout set off centre. These decisions are best taken during the visit, in the room itself and at the hour when it is at its brightest.
Large format, hexagonal terracotta, cement tiles: three different ways of laying
Large-format porcelain stoneware asks for flatness, double bedding and fine joints. Its advantage is its surface: few joints, so few lines to break up the space, and easy cleaning. What it demands is the substrate, as above.
Hexagonal terracotta, old or new, is never perfectly gauged. It is laid with a slightly wider joint, accepting what is irregular in fired clay — which is precisely where its value lies. Reclaimed old terracotta is cleaned, made good and sealed; it cannot be replaced with an imitation without that showing.
Encaustic cement tiles are porous and will stain before they are even laid if care is not taken. They are sealed before laying, then again after grouting, with a suitable water-repellent. The grouting is done in small areas and wiped off quickly: a grey grout left to dry on a pale pattern is embedded in it for good.
Wall tiles, finally, go on a flat and sound substrate, and in a wet room on a continuous waterproofing system. A wall is not a floor: it does not forgive adhesive built up to take up a level, which ends up reading as a ripple under the lighting.
Joints, thresholds and skirtings: what shows in five years
A joint is not a decorative finish, it is a working part. It absorbs the movement of the substrate, it keeps water out, and its colour decides how the whole floor reads: a contrasting grout draws every tile, a tone-on-tone grout erases the grid. That choice cannot be revisited afterwards.
A tiled surface needs to breathe. Around the edges, a flexible joint against the walls; in large rooms, a movement joint; and at the passage from one room to the next, a threshold that allows for movement. It is the absence of those three that cracks a new tiled floor, never the quality of the tile.
That leaves the junctions: the meeting with a wood floor, a stair nosing, the return behind a radiator, the passage under a door. These are areas of a few centimetres, and they are exactly the ones the eye checks on the way in. They are in the quotation, like everything else.
