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Wall tiling is one of those jobs that rewards people who take their time on the boring bits. The cutting, the grouting, the finished look — that's the part everyone sees. But all of it stands or falls on what you do before the first tile goes up.
I've tiled hundreds of walls across 15 years — kitchen splashbacks, bathroom walls floor-to-ceiling, wet rooms, shower enclosures. The same mistakes crop up again and again. This guide will stop you making them.
Key Takeaways
- Proper substrate prep is non-negotiable. No amount of good adhesive fixes a failing wall.
- Set out your tiles before you mix anything. Getting this wrong costs you tiles.
- Use a T-rated (non-slump) adhesive on walls, not floor adhesive.
- Grout joints on walls are typically 2–3mm. Don't go tighter than 1.5mm on standard ceramic.
- Silicone at all changes of plane — never grout a corner or the bath/wall junction.
What You'll Need
Get everything on site before you start. Running out mid-job — especially mid-adhesive — is how mistakes happen.
Tools
| Tool | Notes | Where to Buy | |---|---|---| | Tile cutter (manual) | For straight cuts. Sigma or RUBI for pro results. | See below | | Angle grinder + diamond disc | For L-cuts, notches around sockets and pipes | View on Amazon → | | Notched trowel (6mm V-notch) | Standard for wall tiles up to 300×600mm | View on Amazon → | | Notched trowel (10mm) | Large format wall tiles 600mm+ | View on Amazon → | | Spirit level (1.2m) | For plumb lines and checking beds as you go | View on Amazon → | | Tape measure | | View on Amazon → | | Tile spacers (2mm or 3mm) | 2mm for wall tiles, 3mm if tiles are off-square | View on Amazon → | | Grout float | For pushing grout into joints | View on Amazon → | | Grout sponge | Not a regular sponge — the proper float sponge | View on Amazon → | | Bucket and mixing paddle | Slow-speed drill for adhesive. Don't mix by hand. | View on Amazon → | | Tile trim (if required) | Aluminium or PVC edge trim for exposed tile edges | View on Amazon → | | Silicone gun | For bath/wall and corner joints | View on Amazon → | | Pencil and chalk line | For setting out | | | Batten (50×25mm timber) | Support batten for the first row — see set-out section | |
Tile cutters I'd recommend:
- Sigma 4BU 70cm — Check price on Amazon UK — my daily cutter, handles everything up to 70cm clean
- Sigma 4DN 95cm — Check price on Amazon UK — large format tiles 800mm and above
- RUBI Slim G2 — Check price on Amazon UK — solid choice if you're tiling occasionally rather than daily
Materials
- Wall tile adhesive (C2 T-rated — see adhesive section below)
- Grout (sanded for joints 3mm+, unsanded for 1.5–2mm)
- Silicone (colour-matched to your grout)
- SBR bonding agent or tile primer (depending on substrate)
- Tile trim for any exposed edges
Step 1: Prep the Wall (Substrate Types)
This is the part most DIYers rush. Don't.
The substrate — the surface your tiles are going onto — has to be solid, flat, clean, and not moving. If it isn't, your tiles will crack, pop, or fall off. No adhesive in the world fixes a bad substrate.
Plasterboard (dot and dab or direct fix)
Plasterboard is one of the most common wall surfaces in UK homes, and it's perfectly fine to tile onto — but only if it's fixed properly.
Dot-and-dab plasterboard (stuck to the block wall with dabs of adhesive) has one problem: if you push a tile hard against it, the board can flex between the dabs. On a large tiled area, that flex eventually cracks the adhesive bond.
For a small kitchen splashback, existing dot-and-dab plasterboard is usually fine. For a floor-to-ceiling bathroom wall or a full shower enclosure, fix additional screws between the existing fixings — 300mm grid is the target — before tiling. This stiffens the board and kills the flex.
In wet areas (showers, wet rooms): Use moisture-resistant plasterboard (green board) and prime it with a waterproofing membrane or tanking slurry before tiling. Standard plasterboard in a shower will fail.
Browning/Hardwall Plaster
Fresh plaster needs to cure fully before you tile — 4–6 weeks minimum for a 3mm skin coat, longer for deep patches. Tiling over uncured plaster traps moisture, causing suction problems with adhesive and long-term bond failure.
Once cured, prime with SBR (diluted 1:4 with water) and let it go tacky before applying adhesive. This reduces suction and gives the adhesive somewhere to key into.
Bottom line: Test fresh plaster by pressing your thumb firmly against it. If it leaves a clean indent with no crumbling, it's not fully cured. If it's solid and shows no movement — that's your green light.
Tile Backer Board (Hardie Board, Wedi, Schlüter Kerdi-Board)
Tile backer board is the right substrate for wet rooms, shower enclosures, or anywhere that water contact is regular. It doesn't rot, doesn't swell, and gives you a rigid, flat surface to tile onto.
Fix it with screws at 200–250mm centres into the studs. Tape the joints with alkali-resistant fibreglass tape and fill with flexible adhesive or joint compound. Then tank it (apply a waterproofing membrane) before tiling.
If you're doing a shower, don't cut corners here. Tile backer + tanking is the correct method. Plasterboard in a shower is a water-damage claim waiting to happen.
Painted Walls
You can tile over sound, well-bonded painted surfaces — but you need to key them first. Use a multi-tool or coarse sandpaper to scratch up the surface, then prime with SBR or a dedicated tile primer.
Never tile over peeling, flaky, or damp paint. Strip it back to a solid substrate first.
Never, ever tile over wallpaper. Not even if it looks perfectly flat and stuck down. The adhesive will wet the paper, the paper will release from the wall, and your tiles will come off with it. Strip it. All of it.
I pulled off a whole kitchen splashback three months after install — not my job, I was there to fix it — because the previous tiler had tiled straight over a layer of thick vinyl wallpaper. Every single tile came off clean. The customer was furious. Don't do it.
Step 2: Set Out Your Tiles
Setting out is planning where every tile sits before any adhesive goes on. It takes 30 minutes and saves you from cutting the first row into tiny slivers at floor level or ending up with a 20mm strip at the ceiling.
Find Your Centre Line
Measure the width of the wall and mark the centre point. From that centre, lay your tiles out dry on the floor to see how they'll fall at each edge.
You want a balanced layout — ideally equal cuts at both sides. If the centre layout leaves a thin sliver at one edge (less than half a tile), shift the centre line by half a tile width.
Mark a true vertical line using a spirit level. This is your reference line for every vertical course.
Set the First Row Height
The trickiest row on most walls is the first one — the one that sits just above the bath, worktop, or floor. These surfaces are almost never perfectly level.
The standard method: find the lowest point of the bath/floor/worktop, mark up one full tile height from that point, and fix a temporary horizontal batten at that height. Your first full row of tiles sits on this batten. The cut row to accommodate the bath/floor variation goes in last, once the adhesive above has cured.
This gives you a wall full of level, full-height tiles. The cut row at the bottom is hidden by the bath or skirting, or is the last thing you do once everything is solid.
The batten method sounds like extra work but it's the difference between a level wall and one that's visibly off after the bath is in. I've seen walls where the tiler set off the bath edge — which was 12mm out of level across 1.8m — and you could see the tilt from across the room.
Make a Tile Gauge Rod
A tile gauge is a simple tool — a length of timber with tile-widths marked off including the grout joint. You hold it against the wall and see exactly how tiles will fall. Make one. It takes five minutes and stops you misreading your measurements.
Step 3: Mix Your Adhesive
Use a wall tile adhesive rated C1 or C2, T (non-slump). The T-rating is non-negotiable for walls — it means the adhesive won't slide down the wall once applied. Floor adhesive is not T-rated and will slump.
For standard ceramic wall tiles (up to 400×400mm): C1 T is fine. For larger tiles (600×300mm and up), porcelain, or anywhere that's a wet room: C2 T or C2 S1 T.
Mix to a smooth, peanut-butter consistency. No dry lumps. Use a slow-speed drill with a paddle — not a high-speed drill, which whips in air bubbles. Mix and let stand for 5 minutes (slake), then mix again briefly before use.
Don't mix more than you can use in 20–30 minutes. Adhesive that's started to skin over is dead — bin it, don't try to re-wet it.
Full adhesive selection guide.
Step 4: Butter and Bed the First Row
Apply adhesive to the wall with the flat side of the trowel first — this presses adhesive into any surface texture and gives the notched bed something to key into. Then comb through with the notched side at a consistent 45° angle. Consistent notching matters — uneven combing means uneven tile beds.
For standard wall tiles (up to 300mm): a 6mm V-notch is correct. For larger tiles (300–600mm): use an 8mm or 10mm square notch and back-butter the tiles as well.
Back-buttering: apply a thin skim of adhesive to the back of the tile before pressing it to the wall. On large format tiles this is essential — it fills any surface irregularities and gets you full coverage behind the tile. Aim for 80–85% contact minimum on wall tiles; 90%+ in wet areas.
Press each tile firmly into position with a slight twisting motion, which collapses the notches and improves contact. Check level as you go — don't wait until you've done a row to find out it's run off.
Use 2mm spacers between tiles. On your first row, drop a pair of 2mm wedge spacers under each tile to create a consistent gap above the batten.
Step 5: Work Up the Wall
Work in sections of approximately 1m² — apply adhesive, lay tiles, check level, move up. Don't try to tile the entire wall in one go and then level it at the end.
A few things to stay on top of:
- Check plumb and level every 3–4 tiles. Small errors compound. Catching them early costs nothing. Catching them at the end costs you tiles.
- Keep grout joints consistent. If your spacers are 2mm, they're 2mm everywhere — walls, corners, the lot.
- Don't bridge movement joints. If there's a structural movement joint in the wall, carry it through the tiling. Never tile across it solid.
- Wipe adhesive off tile faces immediately. Once it cures, getting it off without damaging grout joints is a pain. Keep a damp cloth to hand.
- Watch your open time. Most adhesives have a 20–30 minute open time. If the surface has started to skin, scrape it off and apply fresh.
Step 6: Cutting Around Obstacles
This is where most DIYers slow down — sockets, light switches, tap holes, shower tray upstands. Don't panic. Each cut is just a measurement problem.
Electric Sockets and Light Switches
Turn off the circuit at the fuse box before you start. Pull the socket or switch face plate off so you can tile behind it. Measure the tile, mark the cut, and make a straight cut with your manual cutter or angle grinder.
Most socket boxes are close to full-tile width — you'll often only need one straight cut to fit the tile around them. If the socket falls mid-tile, you'll need an L-cut: two straight cuts meeting at a corner. Use an angle grinder or a jigsaw with a tile blade for those.
Tap Holes and Pipework
Use a diamond core drill bit. Mark the centre of the hole with a felt tip, make a small indent with a centre punch (to stop the drill skating), and drill at low speed with water cooling if you can manage it. Don't rush it. Let the bit do the work.
For tiles that straddle a pipe, cut the tile in two through the centre of the hole. Each half will sit either side of the pipe and the joint will be hidden by the escutcheon plate.
Shower Tray Upstand
The row of tiles that sits just above a shower tray is cut to match the tray height. Cut them to exactly the right height and use a neat bead of silicone (not grout) at the tray-to-tile junction. The silicone is the waterproof joint here — grout is porous and will fail in a wet area.
I've seen bathroom jobs where the tiler grouted the tray-to-wall junction and the homeowner called two years later with damp behind the tiles. Silicone moves with thermal expansion; grout doesn't. Use the right material in the right place.
Step 7: Grouting
Leave adhesive to cure fully before grouting — minimum 24 hours for standard adhesive, 48 hours for flexible S1. Don't rush this.
Remove spacers before you grout. If you've tiled onto a batten, remove the batten first and fill the bottom cut row.
Mix grout to a smooth, stiff consistency — stiffer than you think. Runny grout slumps out of the joints before it can cure.
Apply with a grout float held at 45° to the tiles, pressing grout firmly into joints with diagonal strokes. Work a section of about 1m² at a time.
After 5–10 minutes (depends on the room temperature and grout brand — check the packet), wipe excess grout off tile faces with a damp sponge. Wring the sponge well — too much water dilutes the grout and weakens it. Work in circular motions, then straight strokes to clean up.
Repeat until the surface haze is gone. Final polish with a dry cloth once the grout has hardened.
Grout selection:
- Unsanded (fine) grout — for joints up to 2mm
- Sanded grout — for joints 3mm and above
- Epoxy grout — for joints in commercial or high-traffic areas; difficult to work with, very durable
Step 8: Silicone and Sealing
Silicone goes at every internal corner and at the junction between the tiles and any adjacent surface: bath rim, shower tray, worktop, floor.
These joints must be silicone, not grout:
- Bath rim to wall
- Shower tray to wall
- Wall-to-wall internal corners
- Tiles to worktop
Grout cracks in these locations because the two surfaces move independently. Silicone accommodates that movement. Use a colour-matched silicone to your grout for a tidy finish.
Apply a neat bead, smooth with a wet finger (or silicone tool), and tape-mask either side if you want clean lines. Remove the tape before the silicone skins.
Sealing Grout on Kitchen Walls
Standard cement-based wall grout on a kitchen splashback will benefit from a grout sealer — it stops oil and grease soaking in and staining. Apply after the grout has fully cured (3–7 days), clean the surface first, then wipe the sealer in with a cloth. One coat is usually enough.
In a bathroom, grout sealer is optional but doesn't hurt. In a wet room or shower, use an epoxy grout instead — it's impervious and doesn't need sealing.
Common Mistakes and How to Fix Them
Tiles slipping down the wall mid-job. You're using floor adhesive or your wall adhesive is too wet. Scrape the adhesive off, let the wall dry, and use a correctly rated T (non-slump) adhesive.
Grout joints running off-line. Spacers drifted or you didn't check level regularly enough. On a small area you can sometimes pull individual tiles while the adhesive is still fresh and reset them. On a large area that's set — there's no easy fix. Prevention is everything here.
Adhesive curing before you've pressed all tiles in. You mixed too much or the room is warm and speeding up the cure. Work in smaller batches. If the surface has skinned over, scrape it off and apply fresh.
Grout cracking along the bath/wall junction. That's the movement joint. Rake out the grout, clean the joint thoroughly, and fill with silicone. This is the correct material for that joint.
Hollow sound behind tiles. Tap each tile with your knuckle after the adhesive cures. A hollow tap means poor coverage — air pockets behind the tile. If it's in a wet room, that tile needs to come off and be re-laid with better coverage. In a dry area (kitchen splashback) it may be acceptable, but it's not ideal.
FAQ
Can I tile straight onto plaster?
Yes, if the plaster is fully cured and sound. Fresh plaster needs 4–6 weeks to cure — tiling over uncured plaster is one of the most common causes of failed installations. Once cured, prime with a diluted SBR solution (1:4 with water) before applying adhesive. This reduces the suction and gives the adhesive a better key.
Do I tile to the ceiling or stop at a height?
It depends on the room and your layout. In a bathroom or shower, floor-to-ceiling tiling is standard — it's cleaner and more water-resistant. In a kitchen, a half-height splashback (the area between worktop and the bottom of the units) is the most common approach, typically 400–600mm tall. If you're going half-height, finish with a tile trim on the top row rather than cutting tiles to a straight edge with no trim.
What size notched trowel do I need for wall tiles?
For standard ceramic wall tiles up to 300×300mm: a 6mm V-notch trowel. For tiles in the 300–600mm range: an 8mm square notch. For large format wall tiles 600mm+: a 10mm square notch, and back-butter the tiles as well. Matching the notch to the tile size gets you the right adhesive coverage without wasting product.
How long should adhesive cure before grouting?
At least 24 hours for standard (C1 or C2) wall adhesive at normal room temperature (18–22°C). Flexible S1-rated adhesive typically needs 48 hours. In a cold room or damp conditions, allow longer. If you grout too early, the moisture from the adhesive still curing has nowhere to go — it can cause ghosting through the grout and weaken the adhesive bond.
Do I need to seal grout on a kitchen wall?
It depends on the grout. Standard cement-based grout on a kitchen splashback will absorb oil and grease over time, leading to staining that's hard to clean. A grout sealer applied after the grout has fully cured (allow 3–7 days) will protect it. In a wet room or shower enclosure, use epoxy grout instead — it's non-porous and doesn't require sealing.
How do I tile around a recessed shower shelf or niche?
Tile the back wall of the niche first, then the sides. Use a tile trim on the front face of the shelf to create a clean, finished edge. The trim sits proud of the tile and covers the cut edge. Silicone the internal corners of the niche — don't grout them. Use a spirit level throughout; a shelf that's even slightly off-level will show water pooling on one side every time.
Sources
- British Standards Institution, BS 5385-1:2009 — Wall and floor tiling. Code of practice for the design and installation of internal ceramic and mosaic wall tiling and mosaic in normal conditions. (UK standard for wall tiling method and materials.)
- Tile Association (TTA), Adhesive and Grout Selection Guide — tileassociation.co.uk (guidance on EN 12004 adhesive classes and correct substrate preparation for domestic installations.)
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