Module 2 of 2 · 45 minutes
Setting out, cutting and grouting
By the end of this module you will be able to
- Set out a wall or floor so the cuts fall where they look right
- Cut tiles accurately, including holes and mitres
- Grout and finish without staining or cracking
- Seal junctions correctly with silicone
Work through it
1 interactive for this module, built on the WAJD Teach engine. Nothing moves until you ask it to, and every one has a written version if you would rather read it.
Amara Where do I start? A corner seems obvious.
Nadia It is obvious and it is wrong, and it is the mistake that shows for twenty years. Rooms are not square. Start in a corner and the first row drifts, and by the far wall you have a tapering cut.
Amara So where?
Nadia Find the centre, work outwards, then look at what the edge cuts become before you commit to anything.
Amara And if the edge cut is tiny?
Nadia Shift the whole layout by half a tile, so both ends get a decent cut. Two half tiles look deliberate. One full tile at one end and a twenty millimetre slip at the other looks like somebody made a mistake, because somebody did.
Amara Where should the cuts go?
Nadia Where nobody looks. Behind the door, under the bath, at the bottom. And never at eye level on the wall you see first from the doorway.
Amara Do I start from the floor?
Nadia Never. Fix a level batten and support the first full row on that. Floors are not level, and tiling off a floor puts the whole wall out of true by the time you reach the top.
Amara So the bottom row?
Nadia Cut last, once everything above has set. Take the batten off and fit the bottom row into whatever gap the floor has actually given you.
Amara Cutting. I have a manual cutter.
Nadia Fine for straight cuts in ceramic. Porcelain is much harder and you will want a wet saw with a diamond blade, and you will be glad of it.
Amara Holes for pipes?
Nadia Diamond hole saw with water. And for notches and curves, a grinder from the face, several shallow passes rather than one deep one.
Amara Is dust an issue with tile?
Nadia A serious one. Tile and porcelain are high in silica, and cutting them dry indoors without extraction is one of the more damaging things done routinely on domestic jobs. Wet cutting is not about a neater cut, it is about your lungs.
Amara When can I grout?
Nadia Once the adhesive has cured, which is usually at least twenty four hours and is printed on the bag. Grout too early and you trap moisture and solvent, and you get patchy colour you cannot correct afterwards.
Amara How do I actually apply it?
Nadia Diagonally across the joints with a rubber float, so it packs in rather than skimming over. Then remove the excess diagonally as well.
Amara Then sponge it?
Nadia Damp sponge, rinsed frequently, in stages. And do not flood it, which is the commonest grouting fault there is.
Amara What does flooding do?
Nadia Washes the cement out of the joint. You are left with a weak, pale, powdery line that looks wrong and fails early.
Amara There is always a haze afterwards.
Nadia There is, and you polish it off dry with a cloth. People attack it with more water, which washes more cement out and makes it worse, so they add more water. It is a loop.
Amara Last thing. Corners.
Nadia Silicone, never grout. Internal corners, wall to floor, around baths and trays and worktops, and the perimeter.
Amara Because they move.
Nadia Two planes moving relative to each other, and grout is rigid. Grout hard into a corner and you get that crack along the bottom of the wall that is in every bathroom in the country.
The written material
Setting out decides how it looks
Never start in a corner. Rooms are not square and the first row will drift, and by the far wall you will have a tapering cut that everybody notices for the next twenty years.
Find the centre and work outwards, then check what the edge cuts become. If you are left with a sliver, shift the whole layout by half a tile so both ends get a decent sized cut. Two cuts of half a tile look deliberate; one full tile and one twenty millimetre slip looks like a mistake.
Put the cuts where they are least seen: behind the door, under the bath, at the bottom, and never at eye level on the wall you look at from the doorway.
Fix a level batten to support the first full row on a wall and work up from it. Floors and walls are rarely level, and tiling off a floor is how a whole wall ends up out of true. Cut the bottom row last, once everything above is set.
Cutting
A manual score and snap cutter is fast and clean for straight cuts in ceramic. Porcelain is much harder and usually needs a wet saw with a diamond blade.
For holes, a diamond hole saw with water. For notches and curves, a grinder with a diamond blade, cut from the face, taking several shallow passes rather than one deep one.
Cutting generates respirable crystalline silica, and tile and porcelain are high in it. Wet cutting suppresses the dust and is the reason wet saws exist. Dry cutting tile indoors without extraction and respiratory protection is one of the more damaging things done routinely on domestic jobs.
Cut edges go where they will be covered or where they face away. An exposed sawn edge on an external corner is why mitred edges and trims exist.
Grouting, and where silicone goes instead
Wait until the adhesive has cured, which is usually at least twenty four hours and is on the bag. Grouting too early traps solvent and moisture and produces patchy colour that cannot be corrected.
Work the grout diagonally across the joints with a rubber float so it packs in rather than skimming across. Remove the excess diagonally too, then clean with a damp sponge, rinsed frequently, in stages.
Do not flood it. Too much water washes cement out of the joint, leaving it weak and pale, and it is the commonest grouting fault. The haze that appears as it dries is polished off with a dry cloth, not scrubbed off with more water.
Silicone, not grout, at every internal corner, at the junction of wall and floor, around baths, trays and worktops, and at the perimeter. These are all places where two planes move relative to each other, and grout is rigid. Grouting hard into a corner is why that crack appears along the bottom of the wall in every bathroom you have ever seen.
- Let the adhesive cure fully before grouting, usually 24 hours minimum
- Pack diagonally with a rubber float, remove diagonally
- Clean in stages with a damp, frequently rinsed sponge, never flooded
- Polish the haze off dry, do not wash it off
- Silicone every internal corner and change of plane, never grout
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