How To Install Porcelain Floor Tiles

It's easy to see why porcelain floor tiles are such a popular choice for floors at home. With the charm of wood, the hardness of stone and the durability of vinyl, they'll offer a long lasting, stylish look in any space.

But to ensure a long-lasting finish, it's vital that your new tiles are correctly installed, to avoid any issues further down the line. Porcelain tiles are a little trickier to fix than ceramic tiles and other materials, so it's always best to call on a professional tiler.

However, if you are looking to tile yourself then read on - this guide covers what you need to know. Please bear in mind that we can’t possibly cover all bases as every home is completely unique.


What’ll you need

Aside from your tiles, you'll also require:

  • Tile adhesive and grout
  • Tile cutter
  • Primer
  • Spacers
  • Tape measure
  • Builder’s pencil
  • Notched trowel
  • Tile cutter
  • Grout float
  • Washboy
  • Bucket and sponge
  • Spirit level
  • Rubber mallet
  • Safety gear (gloves, goggles and knee pads are a must)

Depending on your project, you may also need:

  • Silicone sealant
  • Sealer


First things first

The key to a great finish? It's all in the prep, especially if you're re-tiling an existing floor.

You'll want to make sure everything is just right - the subfloor is level and clean, there's plenty of space to work in and you've run through what you need to do.


Plan the layout

For the purposes of this article, we’ll assume you’ve already decided on your tiling pattern.

Once you’re settled, you need to ‘set out’ the exact position of your tiles to make sure you’re happy. While we prefer to draw this out on a sheet of graph paper, you can mark the position of the tiles on the wall itself or even lay them out.

  • A symmetrical look is usually preferable
  • Try and plan so that you can avoid small 'slithers' of cut tiles
  • Don’t forget to allow for grout joints between tiles
  • Plan ahead so that you'll finish your tiling by the door


Correct adhesives

For floor tiling, it's imperative to use a cement-based flexible tile adhesive. These are generally available with different drying times and colours:

  • Standard set adhesives offer you more 'working' time
  • Rapid set adhesives cure quicker, so you can grout the same day
  • Use white adhesive with lighter grout colours
  • Use grey adhesive with grey and darker grout colours

To mix the adhesive, you’ll need a drill and paddle mixer:

  • Add adhesive to clean water in a bucket, as per the manufacturer’s instructions
  • Start on a slow speed and mix until the desired consistency is reached
  • Never add water to the adhesive mix as this can weaken the bond

Please note that ‘ready mix’ paste adhesives must not be used to fix porcelain tiles.

Choosing the right trowel

You’ll need to use a notched trowel to spread the adhesive onto your floor. These feature either U or Square notches, in a variety of sizes.

Choosing the right size trowel is really important - you need to ensure there’s a full bed of adhesive behind a tile. For help determining which size trowel you need, please take a look here.

Preparing your surface

So, we’ve determined our layout, chosen our adhesive and picked our trowel of choice. There’s just one last step before we get going. That's making sure the substrates - the surface we’re going to be tiling - is ready to go.

This means it should be:

  • Completely level and dry
  • Free of any dust or dirt
  • Free of any movement
  • Where necessary, primed with a suitable primer. Never use PVA.

Let’s take a quick look at some of the most common floor substrates in the UK:


Floorboards

We don't recommend tiling directly to your floorboards, as they are liable to move which can cause cracking.

Instead, you will need to overboard with either plywood or dedicated tile backing boards, before tiling as normal. Prior to this it's important to make sure there's no movement or deflection in the floorboards - so make sure they are well screwed down into the joists below.

Plywood

  • We recommend 18mm WBP Plywood
  • You will need to screw into the floorboards at 200mm centres
  • Never fix the Plywood directly to the joists


Tile backing boards

Tile backing boards are quickly becoming the preferred option to plywood, as they offer less of a 'build-up' in floor height, are easy to work with and may offer excellent insulating properties.

  • 6mm cement backer boards offer a rigid, low-height solution
  • Foam backer boards are ideal for use in wet areas and with electric underfloor heating mats

As with plywood, you will overboard your current floorboards.


Existing tiles

We don’t advise tiling onto existing tiles, but if you must then ensure they’re fully bonded to the original substrate. Any loose tiles must be removed and made good.


Concrete / anhydrite screed

Concrete and anhydrite screeds are often found in new build properties. These should be left to dry before tiling - it's best to ask your screed installer how long this will take.

  • Any dust, dirt or laitance must be removed from the surface
  • Moisture readers can be used to check the moisture level
  • Screeds often have 'wet' underfloor heating pipes embedded in

Underfoor heating

Many floor tile projects incorporate either electric mats or water-based underfloor heating systems.

These go beyond the scope of this article, but in general:

  • Electric mats must be fitted by a qualified electrician
  • They are generally laid onto foam tile backing boards
  • They are well suited to renovation projects and smaller floors
  • Water-based underfloor heating systems are well suited to larger projects or new builds
  • They are often embedded into a screed

Due to the heat outputs involved with underfloor heating, there may be more movement in the subfloor.

Anti-fracture mats

Also called de-coupling membranes, anti-fracture mats are designed to help prevent the risk of your tiles cracking by absorbing some of the lateral movement in the floor below.

We'd recommend using a mat if you're going to be using underfloor heating. Most anti-fracture mats are relatively thin and are fixed to the substrate using rapid-setting flexible tile adhesive. Once this has set, you can tile onto the top of the matting as normal.

Self-leveller

The use of self-leveller is recommended if your current subfloor isn't perfectly flat. They're easy to mix and pour and will leave you with a smooth, level surface.

It's recommended to use self-leveller with underfloor heating mats as the compound will cover the electric cables.


Waterproofing

If you’re going to be tiling a ‘wet area’ such as a bathroom floor, we’d advise using foam tile backing boards, where possible.

These are generally highly resistant to water, if installed correctly - you’ll need to attach waterproofing tape and corners to the joints and edges between individual boards. Tanking pastes can then be used to further seal these joints and any screw heads.

Priming

Just before you start tiling, we recommend priming your surface with a suitable primer. It’s a vital - yet often overlooked - component of tiling.

This helps to stabilise and seal the surface, increasing the strength of the adhesive bond and prolonging the ‘working’ time. Usually, you want the primer to be touch dry before applying the adhesive.

The tiling itself...

Ready to go? Just before you make a start, it's always a good idea to 'dry lay' a run of tiles and ensure you're happy with the end result.

Once you're set, we'd recommend working in small sections of around 1 m2.

You’ll usually start at the centre of the room, and work your way out to each wall.

  • Apply adhesive to the floor using your trowel, held at 45 degrees
  • This will ‘comb’ the adhesive, helping to ensure a full bed behind each tile
  • Place your first tile on the adhesive, with a light twisting and pressing motion.
  • Use a spirit level to make sure it runs true in both directions
  • A rubber mallet can be used to tap and level tiles down
  • Place the next tile in the same way and insert tile spacers fully into the gap, so they can be grouted over
  • Continue until you reach the wall, where’s it likely you’ll need to cut a tile

Continuously check the quality of your work as you go, in particular

  • Are the tiles running straight and level?
  • Are they flat with no obvious lips between tiles?
  • Are they - and the joints between - clear of adhesive?

You can also use a tile levelling system to help lay your tiles as flat and even as possible, without any lips.

Where necessary, you’ll need to remove and re-fit tiles you’re not happy with. It’s much easier now than once the adhesive has set!

Pro tip:
For tiles that measure 60 x 60 cm and larger, we recommend applying a thin layer of adhesive to the backs of the tiles as well, to help ensure a strong bond.


Cutting tiles

It's more than likely that you're going to have to cut some tiles, especially around the edges of your room.

Porcelain is extremely dense compared to other materials and you will need to use a high quality tile cutter.

  • A manual tile cutter can be used for any straight cuts - these provide a quick and clean cutting method.
  • For more complex cuts, we’d recommend a ‘wet’ tile cutter - they’re safer than an angle grinder.
  • With either cutter, you will need to use a high quality diamond blade / wheel.

Pro tip:
As a seasoned pro will tell you, it’s best to “measure twice and cut once”.


Cleaning

It’s really important to clean your tools and tiles as you go.

Give the surface of the tiles a light wipe with a damp sponge to remove any adhesive residue before it hardens.

You may also need to clean out adhesive from the grout joints - if this is the case, try not to dislodge any adhesive behind the tiles.

Grouting

So, you’ve fixed your tiles, fitted your trims and given it all a good clean? Great, then it’s time to get grouting!

Not only does grout provide an important function - stopping moisture and dirt getting in behind the tiles - it’s also considered a key decorative element these days. Contrasting grout colours add impact and highlight your pattern; co-ordinating grouts offer a more seamless style.

  • It going without saying that the adhesive needs to be fully cured
  • If possible, give the tile joints a quick vacuum to remove any lingering debris or adhesive residue
  • Make sure there’s no tile spacers poking through!

To mix the grout, simply add to fresh water and mix. We’d recommend using a drill with a paddle attachment and mixing at a slow speed, rather than mixing by hand.

Once the grout is at the right consistency, allow it to stand for 5 minutes and harden slightly, before remixing for another thirty seconds or so.

Applying the grout is relatively straightforward:

  • Add some grout to your grout float
  • Hold the float at a 45 degree angle and run the grout across the surface of your tiles
  • Work in diagonal lines to your joints, to help push the grout into the gaps
  • Work in smaller sections until you feel more comfortable
  • Try and remove excess grout from the tiles, as you work round

Cleaning

Once you’ve filled all your joints, we recommend using a ‘washboy’ set to clean - these are much, much easier to use than a normal bucket and sponge.

All you have to do is moisten (not drench) the sponge and even the joints out by rubbing the sponge in a gentle circular motion. After working a small area, clean the sponge, remove excess water by pushing along the washboy rollers, and repeat until you’ve finished.

Pro tip
Don’t use too much pressure as this may dislodge or weaken the grout joints


Grout Haze

We haven’t finished yet!

There’s a good chance that the surface of the tiles is covered in grout haze, which can sometimes be almost-invisible. Over time, this haze can cause the tiles to appear dirty as it’ll attract and trap dirt and dust.

You can easily remove the haze by polishing the tiles with a dry microfibre cloth, once the grout has almost set. For any stubborn grout haze stains, we’d recommend using a specialist grout haze remover.

And finally

A great tiling job is part practice, part patience. So take your time - those extra few hours will be worth it, we promise!