Indian sandstone or porcelain paving: which suits your patio?
Porcelain is easier to live with and harder to lay. Sandstone is the reverse. Here is what decides it.
Porcelain absorbs almost no water, so it resists frost and stains unsealed, but each slab needs a bonding primer and a full mortar bed. Indian sandstone is porous and stains, but is easier to cut and lay. For wet grip, ask for the pendulum test value: HSE rates 36 or more as low slip potential.
The short version
- Ask the supplier for a wet pendulum test value, not an “anti-slip” label. HSE classes 36 or more as low slip potential, and 24 or less as high.
- Treat an R rating on a porcelain box with caution. HSE has reservations about the ramp test behind it and says R9, and sometimes R10, surfaces will be slippery when wet.
- Porcelain that is not primed on the back and bedded on full mortar can come loose, whatever its quality. That is a common reason porcelain patios fail.
- In the front garden of a house, more than five square metres of impermeable paving needs permission unless its water runs to a lawn, border or other permeable area, whichever slab you choose.
- Paving firms with a turnover of £36 million or more must publish a modern slavery statement. Some also file it on the government’s free registry, so check there or on the firm’s website before you buy Indian stone.
Side by side
How the two compare on the things that matter outside
Most of the differences come back to one property: how much water the slab takes in. Porcelain is very dense, and under the usual definition it must absorb 0.5 per cent of its weight in water or less. Sandstone is a porous natural material that can absorb water and contaminants. Frost damage, staining, algae and the need for sealing all follow from that.
| Question | Indian sandstone | Porcelain |
|---|---|---|
| Does it take in water? | Yes. How much varies from quarry to quarry and bed to bed. | Almost none. |
| Grip when wet | A riven face has natural texture. Sawn and honed faces are smoother. Green growth on any face is slippery. | Depends entirely on the surface texture the factory gave it. Ask for the wet test figure. |
| Frost | Usually fine if its test data shows it suits frost exposure. Some stone flakes along its natural layers in hard winters. | Little water in the body, so frost has very little to act on. |
| Stains and algae | Oil, wine, rust and leaf tannin soak in. Greens in shade. | Spills and algae sit on the surface and wash off. |
| Sealing | Optional, but common. Needs redoing over time. | Not needed. |
| Laying | Riven slabs vary in thickness, so the mortar bed does the levelling. Cuts easily. | Priming slurry on every slab, full mortar bed, diamond blade for every cut. Little room for error. |
| Looks | Every slab differs. Colour changes with age and weather. | Uniform. Many are printed to look like stone or wood. |
| Repairs later | A replacement slab may not match exactly. | A spare from the same batch matches, if you kept one. |
Neither is the better slab in general. A shaded patio under trees, a path you walk every day in winter, or a family that barbecues a lot all point toward porcelain. An older house with brick or stone walls, a sunny open garden, or a homeowner who wants to lay or repair it themselves all point toward sandstone.
Slip resistance
Grip in the wet: the number to ask for
Ask for a pendulum test value measured wet. HSE treats the pendulum as its standard test for floor slipperiness, and its technical sheet on assessing the slip resistance of flooring sets out the bands: a value of 0 to 24 is high slip potential, 25 to 35 is moderate, and 36 or more is low.
The sheet was written for workplace floors, but it is the clearest published yardstick for any surface people walk on in the rain, and the test uses Slider 96 rubber to represent people wearing shoes.
A lot of porcelain is sold with an R rating instead. That comes from a German ramp test in which people in heavily cleated safety boots walk on oiled samples. HSE says it has reservations about that method, that the R10 band alone covers a very wide range of slip potential, and that R9 (and in some cases R10) surfaces will be slippery when wet.
Two more points from the same HSE sheet change what you should do:
- Lab figures describe a new slab. HSE notes that slip resistance can change significantly after installation, after cleaning, and after short periods of use. If a sealer is going onto sandstone, ask whether it changes the surface, and test a spare slab before you seal the whole patio.
- Dirt and growth change everything. A textured porcelain slab coated in green algae is not the slab that was tested. Shade, overhanging trees and poor falls can matter as much as the choice of material.
For steps and ramps, choose the highest wet figure you can find, and keep the surface clean.
Frost, stains and sealing
What winter and daily life do to each
Porcelain wins on frost and stains because so little water gets in. Frost damage happens when water in a material freezes and expands, and porcelain holds too little water for that to matter. Sandstone varies: Designing Buildings advises checking the stone’s technical information and test data where it will face weather, frost or frequent wetting. Ask the supplier for it.
In practice, much of the frost damage to a patio of either kind starts underneath, not in the slab. A slab laid on a few dabs of mortar has hollows below it. Water collects there, freezes, and lifts the corner, and the damage shows weeks later, after the thaw. The post on frost damage to brickwork and paving explains why. A full mortar bed with no voids protects both materials.
Staining
Sandstone stains. Cooking oil, red wine, rust from metal furniture and the tannin from wet leaves all soak into the surface, and some marks never fully come out. Mortar smeared on the face during laying stains it too, so a careful layer cleans as they go. Porcelain wipes clean in almost every case, which is a strong reason to use it for an outdoor kitchen or under a barbecue.
Sealing sandstone
Sealing is optional. It slows staining and algae and can deepen the colour, but Designing Buildings is clear that sealing is not a substitute for suitable drainage or correct installation. Seal only when the stone is fully dry and clean, and expect to redo it every few years. You can do it yourself with a roller on a dry weekend. Designing Buildings advises avoiding strongly acidic products on sandstone, sealed or not.
Laying
Laying porcelain is less forgiving than laying sandstone
Both should go down on a full mortar bed over a properly compacted sub-base, laid to a fall so water runs away from the house. Since March 2025 the British Standard for installing modular paving, BS 7533-102, covers both natural stone slabs and porcelain slabs, along with every layer above the formation, from the sub-base to the bedding. The full text costs money. The points below are standard trade practice, not quotations from it.
Porcelain
Porcelain is so dense that ordinary mortar struggles to grip it. Every slab therefore gets a priming slurry, a bonding primer brushed onto the back just before it is laid on a wet bed. Skip it, or lay on dabs, and the slabs can come loose and start to rock within a few seasons. That happens with good porcelain as well as cheap porcelain. When you compare quotes, check that the primer and a full bed are written in.
Porcelain also needs a diamond blade for every cut, and it is less forgiving than stone: it chips at the edge, it cannot be dressed by hand, and calibrated slabs show every bump in the bed. Joints are usually narrow and filled with a slurry or resin jointing compound.
Indian sandstone
Riven sandstone is split, not sawn, so slabs in the same pack vary in thickness, and the layer takes up the difference in the bed. That is slower than laying calibrated slabs, but the stone cuts easily, can be dressed by hand, and hides small variations. A careful, fit homeowner can lay a small sandstone patio. Porcelain is harder to get right without practice.
Cutting paving makes harmful dust. HSE’s construction dust information sheet lists sandstone among the materials that produce silica dust, warns against assuming dust levels will be low outdoors, and says that wetting the material beforehand does not work. Use a saw with water fed to the blade the whole time, or on-tool extraction, and a properly fitted mask.
On a drive the question is different. Designing Buildings warns that a thickness suitable for pedestrian paving should not automatically be assumed to be suitable for a driveway. If cars will drive on it, read our comparison of resin bound, block paving and tarmac before choosing slabs at all.
Front gardens
The planning rule applies whichever slab you choose
Planning permission for paving a front garden is about drainage, not material. According to the Planning Portal, you do not need permission if the surface is permeable or the rainwater is directed to a lawn or border to drain naturally. If more than five square metres is covered with an impermeable surface whose water does not run to a permeable area, you do need it.
Porcelain and sandstone laid on a full mortar bed with filled joints are both impermeable for this purpose. Sandstone being porous does not change that. So on a front garden over five square metres, either choose a layout where the paving falls toward a lawn, a planted border or another permeable area, or apply for permission. The rule covers houses, not flats, and it does not apply to a back garden patio. Our post on permeable and impermeable driveways and planning permission goes through the rule and the drainage options in detail, including why permeable surfaces on clay ground often do not drain.
Sourcing
Where the stone comes from, and how to check
Child labour and forced labour are recognised risks in Indian supply chains, and you can see how one paving firm reports them. On the government’s modern slavery register, Marshalls plc lists child labour in India as one of its three priority risks, which it places at tier 3 suppliers and below, three or more steps back from the company. It also lists forced labour, naming China and India.
You can check a supplier yourself. Any company with an annual turnover of £36 million or more has to publish a modern slavery statement. Some also file it on the government’s free registry, so look there or on the firm’s website. Look for what the supplier says about tracing stone back to the quarry and checking the quarry itself, not only the processing yard. Smaller importers are not required to publish, so ask them directly how they know who cut the stone.
Porcelain is not automatically clean either. It has its own supply chain, so ask the same question of it. If no supplier can answer it to your satisfaction, British natural stone or concrete paving are the alternatives.
Cost
What makes one dearer than the other
The dig-out and sub-base cost the same whichever slab goes on top. The difference shows up here:
- Labour per square metre. Porcelain needs priming, slower cutting and a perfectly flat bed. Riven sandstone needs more bedding work to level slabs of uneven thickness. Which costs more depends on the shape of the job.
- Cuts and waste. Curves, steps and lots of corners mean more cutting. Porcelain cuts are slower, and a chipped porcelain slab usually cannot be reused.
- Grade and thickness. Calibrated sandstone costs more than riven but is quicker to lay. Thicker slabs cost more of either.
- Upkeep. Sealing and stain removal on sandstone are ongoing costs. Porcelain’s are lower.
So two quotes for the same area can differ for good reasons. Ask each one to list the sub-base depth, the bed, the primer if it is porcelain, the jointing and the falls, and compare them line by line.
What to do next
Choosing, in order
- Decide what the area is for. Daily wet walking, shade, steps or cooking point to porcelain. Character, an older house or doing it yourself point to sandstone.
- Get the wet pendulum test value for the exact slab and finish. Use 36 or above as your target wherever people walk often.
- For sandstone, ask for the frost and water absorption test data, and find the supplier’s modern slavery statement, on the registry or on their website.
- If it is a front garden over five square metres, plan where the water goes before you choose anything else.
- Get quotes that specify a full mortar bed, plus a priming slurry for porcelain. If a quote says “dot and dab” or does not mention the bed, ask why.
An existing patio that rocks, holds water or has sunk is a different problem, and sunken and ponding paving covers how to tell a base failure from a drainage one. If the slabs are sound but green, a clean may be all it needs, and our exterior cleaning page covers that.
New patios in both materials are part of our patio work and wider driveways and patios service. Thomas Hannen comes out to look at the ground, the falls and where the water will go, and you get a free written itemised quote.
Questions
Common questions
Is porcelain or Indian sandstone more slippery when wet?
Neither is always worse. It depends on the surface finish. Riven sandstone has a natural texture, while sawn or honed stone and smooth porcelain can be slippery. Ask for the wet pendulum test value: HSE classes 36 or more as low slip potential. Algae on any surface makes it slippery, so cleaning matters as much as the choice of slab.
Does Indian sandstone need sealing?
No, but it is often sealed, because sandstone is porous and stains easily. A sealer slows staining and algae, needs reapplying every few years, and can change the surface grip, so test it on a spare slab first. Sealing does not make up for poor drainage or a poor bed. Porcelain does not need sealing.
Why does porcelain paving need a primer?
Porcelain absorbs almost no water, so mortar has very little to grip. A bonding slurry primer brushed onto the back of each slab just before it is laid on a full wet mortar bed gives it that grip. Without one, slabs can come loose and rock within a few seasons.
Is Indian sandstone ethically sourced?
It depends on the supplier, and the risk is a recognised one. At least one large UK paving firm lists child labour in India as a supply-chain risk. Firms with a turnover of £36 million or more must publish a modern slavery statement, and many also file it on the government's free registry, so check there or on the firm's website. Ask any supplier how they trace stone back to the quarry.
Do I need planning permission to pave my front garden with porcelain or sandstone?
Only if you cover more than five square metres with a surface that does not let water through and the water does not drain to a lawn, border or other permeable area. Both slabs on a mortar bed count as impermeable. The rule applies to houses, not flats, and not to back gardens.
Read next
Related advice
The guides below pick up where this one leaves off, and the driveways and patios page covers the work itself and the places we cover, if you would rather have the job looked at.
- Driveways: when you need planning permission, and where the water has to go
- Frost damage to brickwork and paving: why it shows up after the thaw
- Resin bound, block paving or tarmac: which driveway surface?
- A sunken or ponding driveway: base failure or drainage?
Driveways and patios, and where we cover All advice articles
Who wrote this
Thomas Hannen
Thomas owns Bournemouth Roofing & Building and prices every job himself instead of sending somebody else. The company is Bournemouth Roofing & Building Ltd, number 15471719, registered in England and Wales. If you want to talk something through before you commit to anything, the site visit and the written itemised quote are both free.
Free quote
Planning a new patio?
Thomas comes out, looks at the ground, the falls and where the water will go, and gives you a free written itemised quote, whichever slab you choose.