Most tile buying decisions come down to how something looks in a showroom. That works fine until the tile is on a patio in February, or under a kitchen sink, or being cut around a doorway by someone who has just discovered their blade is wrong for the job.
Porcelain earns its reputation on the parts you cannot see in a photograph. This guide covers what porcelain tiles actually are, which technical ratings are worth checking, and how the choice changes for outdoors, kitchens, and the wood and marble effect ranges.
What makes a tile porcelain
Porcelain is defined by water absorption, not by appearance. Under BS EN 14411, a tile qualifies as porcelain when it absorbs 0.5 percent of its weight in water or less. Standard ceramic sits anywhere from 3 to 10 percent. That single number drives almost every practical difference between the two.
The low absorption comes from the clay body and the firing. Porcelain uses finer, denser clay with a higher proportion of feldspar, fired at temperatures typically above 1,200°C. The result is a body that has effectively vitrified, closer to glass than to unfired clay in how it behaves.
Two constructions exist. Glazed porcelain has a decorative layer fired onto a porcelain body, which is how most patterns and stone effects are produced. Through-body or full-body porcelain carries the colour right through the tile, so a chip shows the same shade rather than a pale biscuit underneath. Through-body costs more and is worth it in commercial settings or anywhere impact is likely.
Porcelain versus ceramic versus natural stone
Ceramic is cheaper, lighter and easier to cut, which makes it perfectly sensible for walls and light-use floors. It is not suitable outdoors in the UK and it chips more readily.
Natural stone has depth and variation that no print can fully match, but it is porous. Marble, limestone and travertine all need sealing, and resealing, and they stain from wine, oil and acidic cleaners. In a kitchen this matters daily.
Porcelain is the middle path that has taken most of the market: stone appearance without the maintenance, and durability that suits floors, wet rooms and gardens. The honest trade-off is that a printed surface repeats. Good ranges use dozens of different face patterns to disguise it. Cheap ranges use four, and you will notice.
The ratings that actually matter
Water absorption. Under 0.5 percent for porcelain. Under 0.1 percent is sometimes marketed separately and is genuinely better for freeze-thaw exposure.
PEI rating. A scale of I to V measuring surface abrasion resistance on glazed tiles. PEI III suits domestic floors, PEI IV handles heavy domestic and light commercial, PEI V is for commercial traffic. Wall tiles often carry no PEI rating at all, which is fine as long as they stay on walls.
Slip resistance. Two systems appear on UK spec sheets. The R rating from the DIN ramp test runs R9 to R13, where R10 is a sensible minimum for a wet interior floor and R11 or above is what you want outdoors. The Pendulum Test Value is the measure UK building control and HSE actually reference, and a PTV of 36 or above indicates low slip potential in the relevant condition. Ask for PTV wet, not dry, since dry figures flatter almost any surface.
Breaking strength. Measured under EN ISO 10545-4 and quoted in newtons. It matters most for outdoor pavers and for anything laid on pedestals, where the tile spans rather than sits on a full bed.
Frost resistance. Non-negotiable for UK exteriors. Water entering a porous tile and then freezing is what destroys patios, which is exactly why the 0.5 percent absorption figure makes porcelain viable outdoors when ceramic is not.
Porcelain tiles outdoor
Outdoor porcelain has largely replaced natural stone paving in UK gardens, and the reasons are practical rather than aesthetic. It does not absorb water, so it does not go green with algae the way sandstone does. It does not need sealing. It resists frost. And it cleans with a brush and water rather than a pressure washer and a chemical treatment every spring.
The specification changes outdoors. You want R11 or higher for slip resistance, a PTV of 36 or above in wet conditions, and confirmed frost resistance. Thickness changes too, which brings us to the format that dominates outdoor porcelain.
2cm porcelain tile: what the extra thickness buys
Interior porcelain is usually 8 to 12mm. Outdoor porcelain is typically 20mm, sold as 2cm porcelain tile or porcelain paving.
The extra thickness gives you breaking strength high enough to be laid without a full mortar bed, which opens up installation methods that thin tiles cannot handle. A 2cm tile can be laid directly on grass or gravel for a path, dry-laid on a compacted aggregate base, raised on adjustable pedestals over a flat roof or terrace, or bedded conventionally on mortar over a concrete base.
Pedestal systems in particular are worth knowing about. They let you build a level terrace over an uneven or sloping surface, run drainage and cabling underneath, and lift individual tiles later for access. None of that is possible with 10mm tile.
Axar Tiles stocks 2cm outdoor porcelain including the Eclipse Black range, which is slip-resistant and rated for patios, terraces, pool surrounds and rooftops. Black works well as a grounding tone against lighter planting or paired with timber, though it does show pollen and dust more readily than a mid-grey, which is worth knowing before you commit a whole garden to it.
Wood effect porcelain tiles
The appeal is straightforward: the look of oak or walnut in places where real timber fails. Bathrooms, wet rooms, kitchens, conservatories and underfloor-heated floors all suit wood effect porcelain far better than engineered wood, which moves with humidity and stains with standing water.
One installation detail catches people out. Long plank formats are not perfectly flat, they bow very slightly along their length, which is normal for the manufacturing process. If you lay them in a 50 percent brick bond, the centre of one plank meets the end of its neighbour at the point of maximum bow, and you get lippage, an edge you can feel with a bare foot. Stagger the joints by no more than a third of the plank length instead. Any competent tiler will already know this, but it is worth confirming before work starts.
Wood effect also benefits more than most from a range with high face variation. Real timber never repeats. If a range only has six or eight different plank faces, a large floor starts to look patterned rather than natural.
Marble effect porcelain tiles
Marble effect porcelain solves the specific problem that makes real marble difficult: porosity. Genuine marble etches when lemon juice or vinegar touches it, stains from oil and red wine, and needs sealing on a schedule most households do not keep. In a kitchen or a family bathroom this is a running maintenance job.
Marble effect porcelain gives you the veining without any of that. It does not need sealing, it does not etch, and it wipes clean.
Two things to look for when choosing. First, whether the range includes book-matched panels, where two adjacent tiles mirror each other so the veining flows continuously across the join. Used on a feature wall or a shower end, this is the detail that separates convincing marble effect from obvious print. Second, check how many distinct faces the range carries, since veining that repeats every fourth tile reads as wallpaper.
Axar Tiles carries marble-effect porcelain across the wall and floor ranges, and the same tiles work in bathrooms and kitchens without the maintenance regime real stone demands.
Porcelain tiles in kitchen: floors, splashbacks and worktops
Kitchens ask more of a floor than any other room. Dropped pans, spilled oil, water around the sink, and traffic all day.
For kitchen floors, look for PEI IV and a slip rating of at least R10. Polished porcelain looks striking and becomes genuinely slippery when wet, which is a real consideration in front of a sink or a dishwasher. Matt and textured finishes are the safer choice and hide crumbs and footprints better.
Large format tiles, 600x1200mm and above, reduce grout lines and make a kitchen look larger, but they demand a flat substrate. A floor that is out by more than about 3mm over 2 metres will produce lippage between big tiles, and no amount of adhesive fixes it. Budget for levelling compound if the existing floor is uneven.
For splashbacks, porcelain gives you a continuous wipeable surface behind a hob, and large format panels mean minimal grout to discolour. Some ranges are thin enough to be used as worktop surfaces, though that is a specialist job requiring a fabricator rather than a tiler.
Underfloor heating works well with porcelain, which conducts heat efficiently and is stable at the temperatures involved. Use a flexible S1-class adhesive and follow the commissioning schedule for the heating rather than firing it up the day after tiling.
Sizes, edges and how much to order
Rectified tiles have been mechanically ground to an exact size after firing, which allows grout joints as narrow as 2 to 3mm. Non-rectified tiles have a slight natural size variation and need a wider joint, usually 3 to 5mm, to absorb it. Neither is better, but a rectified tile laid with a wide joint wastes what you paid for, and a non-rectified tile forced into a narrow joint will look uneven.
Order 10 percent more than your measured area for straight laying, and 15 percent for diagonal or herringbone patterns where cuts are less efficient. Keep the offcuts. Check that everything arrives from the same batch number, because shade varies between production runs and a top-up ordered six months later rarely matches.
Cutting porcelain needs a diamond blade and ideally a wet saw. A standard tile cutter that handles ceramic will struggle and chip the edges.
Best place to buy porcelain tile
The variables that actually matter when comparing suppliers.
Samples, and whether you can get them before committing. Screen colour is unreliable, and a tile in your own light against your own cabinets is a different tile.
Batch consistency and whether the supplier holds enough stock to complete your job from a single run.
Whether the technical data is published. A supplier who lists PEI, R rating and water absorption is one who knows what they are selling. A listing with only a photograph and a price is a gamble.
Delivery terms, since tiles are heavy and delivery costs add up quickly. Axar Tiles offers free UK delivery on orders over £500.
Price, but checked properly. Axar Tiles operates a price match promise, so a lower figure found elsewhere is worth raising rather than acting on immediately.
And if you can get to a showroom, do. Axar Tiles has supplied indoor and outdoor tiles across the UK for over a decade, with a showroom you can visit alongside the online range, and seeing a full tile in person answers questions no product photograph can.
Frequently asked questions
What are porcelain tiles made of?
Fine, dense clay with a high feldspar content, fired above 1,200°C until the body vitrifies. The defining specification is water absorption of 0.5 percent or less under BS EN 14411, which is what separates porcelain from standard ceramic.
Are porcelain tiles better than ceramic?
For floors, wet areas and anywhere outdoors, yes. Porcelain is denser, harder, frost resistant and far less absorbent. Ceramic is cheaper and easier to cut, which makes it a reasonable choice for walls and light-use interior floors.
Can porcelain tiles be used outdoors in the UK?
Yes, provided they are rated for it. Look for confirmed frost resistance, a slip rating of R11 or above, and a PTV of 36 or higher in wet conditions. Outdoor porcelain is normally 20mm thick rather than the 8 to 12mm used indoors.
What is a 2cm porcelain tile for?
The 20mm thickness gives enough breaking strength to be laid without a full mortar bed. That allows dry laying on gravel or grass, installation on adjustable pedestals over terraces and flat roofs, and conventional bedding on concrete. It is the standard format for outdoor porcelain paving.
Do porcelain tiles need sealing?
The tile body does not, because it is effectively non-porous. Cement-based grout can benefit from a grout sealer in kitchens and wet areas, and polished porcelain sometimes takes a surface treatment to resist marking, but the tile itself needs nothing.
Are wood effect porcelain tiles convincing?
The good ranges are, particularly at floor level once furniture is in. Two things determine it: how many different plank faces the range carries, and the laying pattern. Stagger joints by no more than a third of the plank length rather than a half, which prevents the lippage that gives cheap installations away.
Is marble effect porcelain better than real marble?
Practically, in most homes, yes. Real marble is porous, etches on contact with acids, stains from oil and wine, and needs periodic resealing. Marble effect porcelain gives the veining with none of that upkeep. Real marble still wins on depth and translucency if maintenance is not a concern.
Which porcelain tiles are best in a kitchen?
Aim for PEI IV or above and a slip rating of at least R10, in a matt or textured finish. Avoid polished porcelain around sinks and dishwashers, where it becomes slippery when wet. Large format tiles look excellent but need a substrate flat to within about 3mm over 2 metres.
How many tiles should I order?
Add 10 percent to your measured area for straight laying, or 15 percent for diagonal and herringbone patterns. Order it all at once and check the batch numbers match, since shade varies between production runs.
Can porcelain tiles be laid over underfloor heating?
Yes, and porcelain suits it well because it conducts heat efficiently and stays stable. Use a flexible S1-class adhesive and follow the heating manufacturer's commissioning schedule rather than switching it on immediately after tiling.
Where is the best place to buy porcelain tile in the UK?
Look for a supplier who publishes full technical data, offers samples before you commit, holds enough single-batch stock for your job, and is clear about delivery costs. Axar Tiles covers all four, with free UK delivery over £500, a price match promise and a showroom you can visit.
