In this guide we will cover how to lay natural stone paving. Natural stone is an enduring and diverse choice when it comes to outdoor tiles. Installed in gardens and outdoor areas for centuries, natural stone remains a timeless option. Renowned for its durability as well as its aesthetic charm, natural stone is a considered investment. The correct installation of natural stone ensures its longevity, and that your stone patio will look beautiful for years to come. Follow our helpful guide for advice on laying your natural stone paving.
Pre-installation check list
Identify your substrate: Prior to installation, it is important to identify your outdoor substrate. A substrate is the surface which sits beneath the pavers - the installation method may vary depending on your substrate. We recommend employing the services of a professional installer who has experience installing outdoor paving as well as your chosen product to achieve the best results.
Acclimatising & cleaning: Natural stone blocks are cut into pavers using water cooled gang saws, the tiles then undergo the appropriate finishing process and are packed immediately. Often the stone pavers retain a lot of this moisture and will not have a chance to dry until they are unpacked - as the stone starts to dry out, you will notice the colour lighten. It is important to install the tiles once fully dry to ensure you can blend the tiles tones and variation to achieve the best result. With this in mind, we advise installing pavers in dryer and warmer months, as supposed to wintertime.
In some instances, the tiles may require an initial clean to free them of surface dirt following the manufacturing process. This should be actioned prior to allowing the pavers to dry.
Dry laying tiles: It is best practice to dry lay your pavers initially to ascertain the optimum grout joints (minimum 3mm) and to avoid any narrow cuts. Please note some pavers will require a wider grout joint. This process also helps to achieve the best blend of tones and variation prior to fixing the pavers - you can inform your tiler of pavers you would prefer to use for cuts.
Levelling the base: It is important the base or substrate you are installing your pavers onto is an even and level surface. Most substrates for natural stone paving will either be a compacted hardcore base or a concrete base. When installing a patio which is adjoining an existing structure it is of paramount importance for the finished level to be at least 150mm below the damp proof course.
Materials needed
Primer: a primer applied to the back of the pavers or to the substrate prior to installation (depending on the base used)
Mortar/Adhesive: used to fix the pavers
Sealant: applied to the pavers as a protective barrier against water and stains
Grout: applied between the pavers
Installation advice
Priming
If laying onto a compacted hardcore base, we recommend priming the back of the pavers with an SBR slurry mix.
If laying onto a concrete base, we recommend priming the substrate prior to installation. A primed base will benefit from lower absorbency and an improved bond strength.
The primer required will be determined by the substrate you are laying the pavers on.
Fixing with mortar/adhesive
If laying onto compacted hardcore, the pavers must be installed onto a full bed of mortar made from 5 parts washed sharp sand and 1 part cement, mixed to a workable consistency.
If laying onto a concrete base, the pavers should be back buttered with a thin coat of exterior grade flexible white adhesive and laid onto a full bed of trowelled adhesive using a 10mm notched spreader. A white flexible adhesive (not grey) must be used to prevent irreversible discolouration of natural stone.
Pavers must be installed onto a full bed of mortar or adhesive – under no circumstances should they be spot or ribbon fixed.
Sealing
Sealant should only be applied once the pavers are clean, fully dry and released of all moisture. Whilst it isn’t essential to seal outdoor natural stone, we do recommend sealing - acting as a protective barrier against water and stains. We advise a minimum of two coats of sealant, one before grouting and one after grouting.
Grout
We always recommend choosing a grout colour that is similar or lighter than the stone paver. With natural stone, it is important not to use grout that is darker than the tile, as this can lead to picture framing. Grouting can only take place once the initial coat of sealant has been applied.
The pavers can be grouted using a rubber spreader, all joints must be fully filled so as not to leave any cavities within the joint. Paving should always be installed with a grout joint of at least 3mm, some pavers may need a wider grout joint. The grout joint should be able to accommodate variation within paver size where necessary.
Read our blog on how to clean natural stone paving for everyday maintenance and care.
We hope this post has been helpful in understanding how to lay natural stone paving. We recommend a visit to one of our UK showrooms to see our natural stone paving on display and please do not hesitate to contact us for advice on your outdoor project. If you’re looking for initial inspiration, learn more from our post on what is the best paving for patios.
All advice is given in good faith. The responsibility ultimately lies with your contracted installer for the correct installation of tiles.
