How to Lay Natural Stone Floor Tiles

How to Guide for interior floor tiles: 10 important steps

STEP1. Planning 

It is always important to first plan out your project taking into account the proposed application of the floor surface, how the area will be used, and the size of the floor that will be covered. Smaller areas often work better with smaller modular tile units or if wanting to achieve a traditional pattern, tiles that have a fixed width with random lengths can be effective. 

We recommended a minimum 10% wastage is considered when ordering your tiles for cuts, and when using natural stone, to also allow for the rejection of some tiles where shade or markings are deemed to be aesthetically unsuitable. It is also worth keeping a few spares for repairs.

It can also be helpful to dry lay the floor first to ensure the most effective use of the pattern you have chosen and minimise where possible small cuts. This also allows you to mix the tiles to ensure a uniformity of fluctuations in shade and tile markings. 

When implementing the installation, ensure you have the correct tools, adhesives and grouts, and where appropriate sealing/ impregnator products to give added protection to your finished surface covering.

It is imperative that personal protective equipment is worn and extra care taken when using power tools designed to cut tiles.  This means gloves, safety goggles/glasses, dust masks, and knee pads should be worn, and on any project, be aware of all manufacturer’s instructions and safety advice.

STEP2 . Tile Preparation

[a] FLOORS:- 

Prior to laying the flooring, an area should be set aside for unpacking and enable you to sort the tiles to allow for colour/texture and thickness variations. Whilst we recommend that the tiles used are always calibrated, there will still be some variation in thickness [which is typically +/-2mm].  When laying the floor use the thickest first and blend the thinner tiles as work progresses.

You also need to clean and prepare your surface before you tile to remove any grease, dirt, or fingerprints, that could inhibit tile adhesion. If tiles are to be sealed it is recommended that they are cleaned prior to installation to remove any dust or dirt that may be present, and when completely dry a sealing application can be applied to the face of the tile. This will also make it easier to clean away adhesive and grout, from the surface.

STEP 3. Assessing the Floor 

[a] FLOORS:- 

The floor must be checked to ensure it is of sound structure, level and smooth and free of any dust, oils or grease.  Any holes or hollows should be filled and levelled.

Timber floors comprised of tongue and groove boards should be overlaid with WBP marine plywood fixed with stainless steel screws at between 200 to 300mm centres.  If the floor has movement and flexibility, 2 layers of marine plywood laid in opposite directions will limit this.  Concrete floors should be assessed for smoothness, if the surface is rough, either the flooring can be laid in a thick bed adhesive, or the floor can be levelled with either sand/cement screed or a self-levelling compound.  Ensure all concrete/screed/self-levelling compounds are fully cured before fixing tiles. 

However, other alternatives are the use of uncoupling matting and membrane products. This type of system uses the separating layer to provide an uncoupling buffer between the tile and the substrate, enabling the substrate to move independently to the tiles. 

Substrates will expand and contract naturally due to humidity and/or temperature fluctuation and this is especially true where under floor or under-tile heating has been installed. 

Any movement, whether shrinkage or expansion, can cause stress cracks that can transfer through to the tiled surface, causing the tile to either fracture, or de-bond from the background. Uncoupling matting helps to prevent these lateral stresses from transferring through to the tiled layer by absorbing these stresses and transferring them evenly over the floor. 

STEP 4. Setting out the floor for tiling

It is generally best practice to identify either the centre of the room or a focal point as the start.  The centre of the room can be found using a tape measure to identify the mid-point of all walls and chalk lines struck from opposite centre points.  Where the chalk lines cross will be the centre.  

Alternatively, the starting point may be the edge of the wall in a room, with thought given to door access points to eliminate or reduce cutting of the tile. 

STEP 5. Laying Tiles 

[a] FLOORS:- 

Using a trowel, apply enough adhesive to the floor to fix at least 2 tiles, starting at the marked centre or focal point of the room. It is important to ensure a bond and also to make any height adjustments, so creating a thin skin adhesive to the back of the tile is advised.

Press the tile into adhesive and using a level to check that the tile is true and make slight adjustments by pressing down firmly.

Continue laying tiles, following a line to the wall, inserting tile spacers if required, to help provide consistent grout joints of between 4 to 7mm. Keep checking levels with the spirit level and grade the tile thickness from the centre.

When purchasing adhesive for your stone tiles you should check the porosity of the material you are laying, as some slates and tiles such as quartzite may need a primer to be applied first. [ see note on porosity levels of stone.] 

Step 6 . Cutting Tiles 

For cutting straight lines, the ideal tool is a diamond blade wet tile cutter, and ensure careful attention to safety instructions and wear suitable PPE ( such as eye protection and gloves).

If an angle grinder fitted with a diamond blade is to be used, this will generate dust, and suitable dust protection should be used.  

Step 7.  Grouting and Pointing

[a] FLOORS:- 

When all tiles are fully set and the floor adhesive has sufficiently cured, tiles can be grouted. Before applying grout, check all joint gaps are clean and any protruding adhesive is scraped away. Mix the grout in a clean bucket following manufacturer guidelines. Ideally use a rubber edged grout spreader to force grout to fully fill all gaps between tiles and clean excess grout with a clean sponge. Once the grout has set, thoroughly clean the tiled area with a sponge and clean water ensuring you remove as much of the cleaning water as possible, as this will contain a grout solution and could leave a residue on the tiles.

Step 8. Surface Sealing

The use of a sealer will depend upon the porosity of the tile being used and where it is being installed. A good quality sealer is paramount, that is designed for the type of stone being installed and can enhance the tiles performance by creating a barrier to dirt and grime that will significantly help care and maintenance as well as minimise damage from alcohols and grease. 

In addition, it is important to note that many sealing solutions can significantly change the appearance of the tile and give different levels of sheen, so always test the chosen sealer on spare tiles before applying.  Good quality sealers will provide long term performance and not significantly change the natural look and feel of the stone surface whether it be for the interior or exterior of the property.

Step 9. Maintenance

Dry dust and dirt can be removed using a brush or dry vacuum or alternatively washed with a suitable detergent solution and rinsed thoroughly before vacuum drying.

Light scuffing and blemishes can be cleaned using a proprietary stone soap cleaner after normal cleaning and drying. Deep scratch damage to can be removed using a fine grade wet and dry sanding sheet.

Oil based stains can be removed with white spirit, but note that this may also remove any surface sealant, and will then need to be repaired. 

 Step 10. Aftercare & Maintenance

All projects, whether paving or an internal floor area require regular care and maintenance to ensure they remain clean and in the best condition possible. It is therefore important to understand the best products and methods to use that will ensure your investment in natural stone lasts for many decades. The simplest form of cleaning is regular brushing, and for interiors an effective specialist cleaner for the surface, that should not be a heavy bleach or chemical compound that that is left standing or it will likely damage the surface.  

The use of specialist cleaning product are always recommended, along with for paving simple light surface hosing. Note heavy power washing can damage the surface and open the stone surface which can further increase the opportunity for dirt and lichens to grow and discolour surfaces.