Porcelain has become the UK's favourite choice for outdoor paving tiles, and it's easy to see why. It's tough, low-maintenance, frost-resistant, and holds its colour for decades. But there's one thing every homeowner and landscaper needs to understand before starting: porcelain paving installation is not the same as laying natural stone or concrete.
Because porcelain is non-porous, it won't naturally bond to a standard mortar bed. Get the method wrong and slabs can lift, crack, or come loose after their first winter. Get it right, and you'll have a stunning patio that lasts a lifetime.
This guide walks you through how to lay porcelain paving correctly, step by step, using the full-mortar-bed method recommended for laying porcelain slabs across the UK.
Before You Start: Tools and Materials
Gather everything you need before laying a single slab:
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Porcelain paving slabs - order all from the same batch to avoid colour banding
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MOT Type 1 sub-base
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Sharp sand and cement (for the mortar bed)
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Slurry primer (the essential bonding bridge for porcelain)
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Porcelain-specific jointing compound / grout
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Rubber mallet, spirit level, straight edge
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Tile spacers (3–5mm)
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String lines and pegs
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Cement mixer or wheelbarrow
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Wet saw or angle grinder with a porcelain diamond blade
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Safety gear: goggles, dust mask, ear defenders, gloves
The golden rule of porcelain paving installation: Never use metal hammers, and never lay porcelain on "five-spot" dabs of mortar. Voids beneath the slab lead to cracking through the UK freeze-thaw cycle.
Step 1: Excavate and Prepare the Base
Mark out your area with string lines and pegs. Excavate to a depth of roughly 150–200mm to allow for the sub-base, mortar bed, and slab thickness.
Remove all vegetation, roots, and topsoil, then compact the ground until firm and even. When laying porcelain slabs, a solid foundation is the single most important factor in a patio that lasts.
Step 2: Lay the Sub-Base
Spread a layer of MOT Type 1 to around 100mm and compact it thoroughly with a plate compactor until level and firm. This layer distributes load and provides drainage - essential for any outdoor paving tiles exposed to UK weather.
Set your drainage fall now. Your patio should slope away from the house at a gradient of roughly 1:80 so rainwater runs off rather than pooling. Use your string lines to establish this fall before you lay any slabs.
Step 3: Mix and Lay the Mortar Bed
Mix a full mortar bed using a ratio of around 4:1 sharp sand to cement - semi-wet and workable, not sloppy. (If you're using a permeable jointing compound later, a weaker 6:1 mix aids drainage.)
Spread the mortar to a depth of roughly 40–50mm, working one slab at a time rather than covering the whole area at once. This keeps the mortar fresh and gives you a full, void-free bed under every slab - a key rule when laying porcelain slabs in the UK climate.
Step 4: Prime the Slab
This is where porcelain paving installation differs from everything else. Because porcelain is non-porous, the back of each slab must be coated with a slurry primer to create a bond between the slab and the mortar.
Brush the primer evenly across the entire underside of the slab, right up to the edges, immediately before laying. Apply it just before placing - if the primer dries out, it loses its bonding strength.
Pro tip: Keep primer off the face of the slab. Once it dries on the surface, it's almost impossible to remove and will leave permanent marks on your outdoor paving tiles.
Step 5: Lay and Level Each Slab
Place the primed slab onto the wet mortar, lowering it one corner at a time for accurate positioning. Tap it gently into place with a rubber mallet until fully bedded - aim for full contact between the slab and the mortar for maximum strength.
Use spacers to keep even joints of 3–5mm, and check every slab with a spirit level and straight edge as you go. Confirm each slab sits level with its neighbours and follows your drainage fall. Wipe away any mortar or primer from the surface immediately - dried residue is very hard to shift.
Step 6: Cutting Porcelain Slabs
For cuts around edges, corners, or drains, use a wet saw or angle grinder fitted with a continuous-rim porcelain diamond blade. Always cut wet to reduce heat, vibration, and chipping, and dry-fit every piece before fixing it. Keep the slab fully supported while cutting to prevent cracking. Clean, accurate cuts are what give a professional porcelain paving installation its finish.
Step 7: Grout and Joint
Only begin jointing once the mortar and primer are fully set. Fill the joints with a porcelain-specific jointing compound - never ordinary mortar, which won't perform on porcelain.
Work the compound firmly into the gaps at a 45-degree angle with a rubber float or squeegee, then wipe the surface clean with a damp sponge before it dries. A pre-grout sealer can help prevent grout haze on textured outdoor paving tiles.
Step 8: Let It Cure
Leave the finished patio undisturbed for at least 24 hours - no foot traffic. If rain is forecast, cover the area with tarpaulin so water doesn't wash through the joints into the curing mortar. Avoid laying in wet weather altogether, as too much water ruins the mortar's consistency.
Common Porcelain Paving Installation Mistakes to Avoid
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Skipping the slurry primer - the number one cause of failed porcelain patios.
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Using dabs of mortar instead of a full bed - leaves voids that crack in frost.
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Forgetting the drainage fall - leads to standing water and staining.
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Jointing with standard mortar - use a porcelain-grade compound only.
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Mixing slabs from different batches - causes visible colour banding across your outdoor paving tiles.
Ready to Start Your Patio Project?
Laying porcelain slabs is well within reach of a confident DIYer, but the prep and priming stages are what separate a patio that lasts decades from one that fails in a season. If your project is large or complex, an experienced landscaper will get the most from a premium product.
Browse our full range of outdoor paving tiles and porcelain paving slabs at Axar Tiles - weatherproof, slip-resistant, and built for UK gardens. Need help choosing? We offer free samples and expert advice, plus fast UK-wide delivery.
Frequently Asked Questions
Do porcelain paving slabs need a slurry primer?
Yes. Porcelain is non-porous, so it won't bond to mortar on its own. A slurry primer brushed onto the back of each slab creates the essential bonding bridge. Skipping it is the most common porcelain paving installation mistake and the top cause of loose or lifting slabs.
What mortar mix should I use for laying porcelain slabs in the UK?
A full mortar bed of around 4:1 sharp sand to cement, mixed semi-wet and workable. Always lay a full bed rather than dabs of mortar to avoid voids that crack in frost.
What gap should I leave between porcelain paving slabs?
Use spacers to maintain even joints of 3–5mm, then fill them with a porcelain-specific jointing compound rather than ordinary mortar.
What drainage fall do outdoor paving tiles need?
A gradient of roughly 1:80, sloping away from your property, so rainwater runs off instead of pooling on the surface.
Can I do porcelain paving installation myself?
Yes, a confident DIYer can lay porcelain paving by following the correct method - solid sub-base, full mortar bed, slurry priming, and proper jointing. For large or complex projects, a professional landscaper is recommended.
