How To Tile A Bathroom Floor
How To Tile A Bathroom Floor
Tiling a bathroom floor may seem difficult but can be a manageable DIY job, even for those with minimal experience, with the right preparation.
Larger-format tiles and stone or wet rooms may need a professional, but for standard tiling jobs, this guide has everything you need to know before laying floor tiles. This includes bathroom-specific factors like moisture and waterproofing, choosing slip-resistant tiles, and ensuring you have neat cuts around the toilet and basin.
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Key takeaways
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Preparation is everything – Clean, level and prime the subfloor and tank the bathroom floor before tiling. A stable, sealed base is what stops tiles cracking or lifting later.
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Start from the centre – Always start from the centre and work outwards, so that irregular tiles sit on the perimeter rather than in the centre. Use chalk lines to find the room’s centre and the 3-4-5 rule to ensure you’re always working with square lines.
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Use spacers and proper adhesive – Ensure you place spacers between tiles and use the right adhesive between the tiles and the subfloor.
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Leave expansion gaps – Don’t pack tiles tightly against the wall or grout before the adhesive has cured, as this will cause the tiles to crack as the floor moves. Leave a 3–6mm gap around the perimeter of the tiling.
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When to call a professional – If your bathroom is a wet room, has an underfloor heating system, or uses natural stone, it’s best to call in a professional. A pro may also be needed for larger-format tiles and for flooring that is badly levelled.
Tools and materials you will need
Before you learn how to lay floor tiles in your bathroom, you’ll need the following tools and materials:
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Electric tile saw – For large-format tiles and awkward cuts.
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Tile nippers – For shaping tiles around curves, notches, and irregular cuts.
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Slip-resistant porcelain or ceramic floor tiles.
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Waterproofing / tanking kit – For the floor and wet zones.
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Mould-resistant flexible grout.
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Flexible silicone sealant – For edges.
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Chalk lines – For finding the centre of the room.
You’ll find these in our tiling tool guide if you’re not sure what to look for.
How many bathroom floor tiles do you need?
To figure out how many tiles you’ll need, measure the area of your floor (length x width) and divide by the coverage per tile or pack. Add 10–15% for cuts and potential future repairs.
Bathrooms have lots of cuts around the toilet, basin, and pipework, so lean towards 15% to be safe. Make sure every box shares the same batch number to ensure consistency across tiles.
How to prepare a bathroom floor for tiling
First you’ll need to remove any old bathroom flooring. Once this has been lifted, check for any leaks or damp that needs fixing before bathroom flooring can be laid down.
Once that’s resolved, make sure you’ve got a stable, primed base before you apply the tiles, as this is what stops them cracking or lifting.
The right prep is different depending on the subfloor, but every bathroom floor must be tanked and waterproofed after levelling and before tiling to function well in a bathroom.
Preparing a concrete subfloor
The most common type of subfloor below ground-floor bathrooms is concrete.
To prepare a concrete subfloor, you’ll need to seal against rising damp, clean off dust, grease, and old adhesive, and ensure the surface is level using a straightedge or level.
If it isn’t level, you can correct dips with a self-levelling compound.
You should also keep in mind that concrete absorbs moisture, so it will need to be sealed or primed before applying adhesive.
Preparing a wooden subfloor
Timber flexes as the atmosphere changes temperature and humidity, so standard floorboards aren’t a suitable base.
In the UK, bathroom subfloors often use chipboard on top of wooden joists. You’ll need to add a layer of tile backer or cement board over the top, as chipboard absorbs moisture extremely easily.
Priming and sealing the floor
Once the subfloor is free of any dirt and grease, and any damp issues are resolved, you can begin to prime and seal the floor.
Priming is an important step in tiling a bathroom floor, as it improves the adhesive bond between the subfloor and the tiles and stops porous surfaces sucking moisture out of the adhesive too quickly.
For general porous surfaces, you’ll want PVA primer, and you’ll want to dilute it at a 1:4 ratio (one part PVA to four parts water). This is usually the case, but it’s important to always check the instructions on your primer before applying it.
Once the primer is dry, you’ll need to tank or waterproof the floor and lower walls. To do this, you can use a tanking kit or waterproof membrane. This should include sealing corners and pipe penetrations, all before laying floor tiles.
Top tip: If you’re tiling a wet room, you should also create a slight slope leading towards the drain before you begin tiling.
How to set out the floor and find your starting point
The first step is to find a starting point. Starting against a wall is never a good idea, as walls are rarely completely square, so your tiles will soon drift out of line.
Instead, connect chalk lines between the midpoints of opposing walls until you’ve pinpointed the centre of the room. After that, dry-lay the floor tiles just to check the layout and to avoid thin slivers at the edges.
Always start from the centre and work outwards, so any irregular or cut tiles end up on the perimeter of the room rather than in the centre.
Top tip: To check your lines are accurately square, use the 3-4-5 rule. Measure 3 units along one line, and 4 along the other. Then measure the diagonal: if it’s exactly 5, your corner is a true 90 degrees.
How to tile a bathroom floor: step-by-step
Work in small sections at a time, so the adhesive doesn’t skin over before you’ve laid the tiles.
Step 1: Mix and apply the tile adhesive
Before laying the tiles, you should first mix the tile adhesive. Choose a flexible, waterproof adhesive that’s suited to bathrooms. Powdered adhesives are typically better than ready-mixed ones for this kind of job, as they chemically cure to absorb moisture and resist subfloor movement.
Mix the powder with water until it reaches a thick but spreadable consistency before using a notched trowel at a 45-degree angle to apply it in parallel lines onto the floor.
Step 2: Lay the tiles and use spacers
Now you can begin to lay the floor tiles. Press each tile with a slight twist to bed it into the adhesive, following along the chalk lines you created earlier.
Insert tile spacers at every joint to keep gaps even, and check across your tiles with a level and rubber mallet to keep everything flat. Failing to use spacers and packing tiles too tightly will leave no space for grouting and will cause tiles to crack as the floor shifts.
Step 3: Cut tiles for edges and perimeter
Precision matters most at the edges and perimeter. Make sure to accurately measure and mark where each tile needs to be cut to fit around any irregular angles or edges where a full tile won’t fit.
Use a manual tile cutter for straight cuts, such as those on the perimeter, and an electric tile saw for more large-format or awkward cuts, such as those bending around curves or corners. Always wear proper protective equipment when using an electric tile saw.
Step 4: Leave expansion joints and let the adhesive set
You should always leave a small expansion gap of 3–6mm at the perimeter and around fixed points. This allows the floor to move without cracking, and will later be filled with flexible sealant. Leave the adhesive to fully cure, which typically takes 24 hours.
Placing tiles too tightly against the wall or filling expansion gaps with hard grout will cause the tiles to crack as the floor shifts.
Step 5: Grout the floor tiles
Once you’re ready to begin grouting your floor tiles, you can remove the spacers you placed between the tiles earlier. Mix your grout to the right colour or type, and then work it into the joints with a grout float, making sure to hold it at 45 degrees.
Wipe off any excess with a damp sponge before it hazes or leaves unwanted residue.
Step 6: Seal the grout, finish the edges and clean up
Leave the grout to cure, and clean up any leftover grout haze. Apply grout or tile sealer where needed, and run some flexible sealant into the perimeter expansion gap you left earlier.
Fit tile trim into any exposed edges to deliver a clean finish.
How to cut tiles around bathroom fixtures
Bathroom floors have more awkward fixtures to work around than most other rooms in a home.
Removing the toilet and basin pedestal first often makes for a cleaner finish. There are a few other factors to consider too:
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Around the toilet / soil pipe – Make a card or paper template of the toilet base and soil pipe. Transfer this onto your tiles and use it to cut the right curve.
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Circular and pipe holes – Use a diamond hole saw for pipe holes, or nibble a circle out of the tiles using tile nippers for smaller pipes.
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L-shaped cuts – These are needed for working around basin pedestals and boxing or door architraves. To create this cut, mark both edges and cut along the long lines with an electric tile saw before finishing the corner with nippers so it doesn’t overrun.
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Which tool for which cut: Tile nippers are best for small curves and nibbling, but electric tile saws and diamond blades are better for larger or more awkward cuts. Hole saws are needed for clean pipe holes.
Top tip: Always dry-fit each cut tile before applying adhesive.
Common mistakes and things to consider
Here are some common mistakes to avoid:
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Starting against the wall instead of the centre – This leaves any irregularities in the centre of the room at the end, rather than along the perimeter.
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Skipping subfloor prep or tiling over a flexing wooden floor – Proper preparation of the subfloor is essential to prevent cracking tiles.
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Mixing too much adhesive – This will cause the adhesive to skin over, meaning the outer layer has already started to cure.
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Uneven adhesive coverage – This can lead to hollow, cracking tiles.
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Forgetting expansion gaps – Packing tiles too tightly without leaving any gaps can lead to them cracking as the floor shifts.
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Grouting before the adhesive cures / using the wrong grout – Using standard grout instead of flexible sealant and applying it too early can cause tiles to crack.
In many cases, tiling a bathroom floor is a simple job for any DIYer. However, if your room has large-format tiles, is made with natural stone, is badly levelled, has an underfloor heating system, or is a wet room, it’s best to call in a professional.