This choice gets made on a showroom sample and regretted on a wet Tuesday two years later. Which is a pity, because the difference between marble and porcelain is not really about how they look — modern porcelain can look extremely convincing — but about what they demand from the building, from the installer, and from you afterwards.
Neither is the right answer. They are answers to different questions, and the honest way to choose is to work out which question you are actually asking.
What they actually are
Marble is metamorphosed limestone: a natural material, quarried in blocks and sawn into slabs and tiles. It is porous. It is calcium carbonate, which means acid attacks it — lemon juice, vinegar, limescale remover, some cleaning products. It has veins, and veins are the point, but veins are also planes of different behaviour within the tile. Colour and pattern vary between batches, within a batch, and sometimes down a single tile. That variation is what people pay for and what catches people out.
Porcelain is clay-based, pressed and fired at high temperature to a dense, near-vitrified body with very low water absorption. It is manufactured to a size and a tolerance. Through-body porcelain carries the colour all the way through; glazed porcelain carries a printed surface, and modern printing is good enough that a stone-effect porcelain will fool most people at eye level and some people at close range.
The parts of this decision that matter in a London flat
Weight, and where it is going
Marble is heavy, particularly in large formats and particularly on walls. Wall tiling in stone has to be supported by a substrate genuinely capable of carrying it, mechanically fixed and prepared properly. Old lath-and-plaster or a tired stud wall in a period conversion is not that substrate as it stands. It has to be made into one, and that is the work — not the tiling.
Then there is getting it into the building. In a mansion block with no parking, a booked lift and a porter, carrying stone up by hand is a real exercise, and it is one of the quiet reasons stone jobs cost what they cost in this part of London. Crated stone is heavy, awkward and unforgiving of being dropped.
Substrate demands
Both materials want a flat, sound, stable substrate, but stone is far less tolerant of an out-of-true wall than a small ceramic tile is. Period London walls are not flat. They bow, they wander and they have been patched by four generations. Preparing that wall — boarding it, battening it, levelling it — is where the hours go, and it is the honest driver behind our tiling price of from £55/m². Anyone quoting stone off a floor area without looking at the walls has not started thinking about the job yet.
Sealing and staining
This is the practical difference that people feel. Marble is porous and needs sealing, and sealing is not a one-off — it is maintenance, repeated on a sensible cycle. Even sealed, marble etches. Etching is not a stain; it is a dull mark where acid has physically eaten the polished surface. Toothpaste, splashes from a bottle of something, or a limescale product used by a well-meaning cleaner will do it. On honed marble it is far less visible than on polished, which is one reason honed is often the wiser specification in a bathroom.
Porcelain does not need sealing and does not etch. You can clean it with almost anything and it stays as it started. If you want a bathroom that requires no thought, this is the whole argument in one sentence.
Slip
Polished marble underfoot, wet, is exactly as sensible as it sounds. Honed or textured finishes are the sane choice for a bathroom floor, and honed marble is a perfectly good floor. Porcelain comes with slip ratings you can specify against, which is a genuine advantage — you can choose a floor tile on evidence rather than on hope. In a wet room, where the whole floor is a shower floor, this stops being an aesthetic question. See wet room versus enclosure.
Grout, and being realistic about it
Grout is a consumable in every bathroom. With marble it is also a risk: some grouts and some pigments can mark porous stone, so the specification has to suit the material and the tiles often want sealing before grouting rather than after. Fewer, larger tiles mean fewer grout lines — which is calmer and easier to clean, but demands a flatter substrate, so you pay for it in preparation.
Lead time and batches
Porcelain is a product with stock. Marble is a natural material selected from a batch, and the batch is finite. If you need more later, matching it may not be possible. Order the whole job at once, with a sensible allowance for cuts and breakages, and accept that the veining you saw on the sample is an indication rather than a contract. Stone lead times are a real factor in the programme, and they are one of the commonest reasons a bathroom start date moves.
Cutting, and why it matters more than you think
Marble cuts cleanly and can be honed, mitred and polished on site by someone who knows how — which is what allows the beautiful details: a mitred external corner with no trim, a niche with the veining running through it, a continuous run around a wall. Those details are hand skill, and they are slow.
Porcelain is hard and brittle. It cuts well with the right blades and it will chip badly with the wrong ones. Large-format porcelain in particular needs proper handling, proper support, and full adhesive coverage on the back — a large tile with voids under it will crack the first time something is dropped on it, and it will crack for good.
In both cases, the difference between an excellent floor and a disappointing one is the person setting it out, not the material in the box.
Underfloor heating
Both work well over heat: dense materials conduct, which is exactly what you want. Marble, being natural, has its own movement characteristics, and over a heated floor the fixing specification — adhesive, decoupling layer, movement provision — matters more than it does with porcelain. It is a solvable problem, and it is solved at specification stage rather than on the day. Our underfloor heating guide covers the build-up.
Living with them
It is worth thinking past the handover, because a bathroom floor has a twenty-year life and you are the one in the room.
Marble asks for a routine. A pH-neutral cleaner, not the supermarket bathroom spray. No limescale remover, ever, which in a hard-water city like London is a genuine constraint rather than a theoretical one — the shower screen wants descaling and the stone next to it does not want the product you would use. Resealing on a cycle. Wiping splashes rather than leaving them. If you keep the routine, marble ages beautifully and develops a patina that porcelain simply does not have. If you do not — or if somebody else cleans the flat and was never told — you get etch marks and dull patches, and the fix is a stone specialist honing and repolishing, not a scrub.
Porcelain asks for nothing. That is the whole proposition. It looks the same in year ten as in year one, the grout is the only thing that ages, and the grout can be raked and replaced. This is why porcelain dominates rentals and why nobody who has ever managed a portfolio argues about it.
The honest summary: marble is a material you have a relationship with. Porcelain is a material you forget about. Decide which of those you want before you fall for a sample.
Which suits which job
Choose marble when
- The building deserves it. In prime Central London stock — a mansion block flat, a period house — real stone reads correctly and buyers and tenants at that level notice.
- You will live with it and you accept the maintenance honestly, including honed rather than polished on the floor.
- You want details porcelain cannot quite do: mitres, continuous veining, a solid threshold.
- Your substrate can take the weight, or the budget covers making it able to.
Choose porcelain when
- It is a rental. This is not a close call. A porcelain bathroom survives tenants, agency cleaners and turnover. Marble does not survive a cleaner with a limescale spray. See refurbishing between tenants and our estate agent page.
- You want a floor with a specified slip rating, particularly in a wet room.
- You want no maintenance regime beyond ordinary cleaning.
- You need certainty of supply and predictable sizes.
- Weight is a genuine constraint.
The mix that usually wins
Stone-effect porcelain on the floor for slip and durability, real marble on a wall or in a niche where it is seen and never walked on or splashed with anything acidic. Or a marble vanity top with a porcelain floor. You get the material where it earns its keep and not where it will only cause trouble.
What to ask before ordering
- Has anyone looked at the walls, or is this priced off a floor area?
- What is the substrate, and what preparation is included?
- For stone: honed or polished, what sealer, and on what cycle?
- Is the whole quantity from one batch, with cuts and breakage allowed for?
- What is the slip rating of the floor tile?
- What is the lead time, and does the programme wait for it?
How we work
Tiling is from £55/m² and it is fixed-quoted against a defined scope once we have seen the walls, because the walls — not the tile — decide the work. Bathroom refurbishment starts from £2,800, and larger refurbishment is per quotation. If your building or your use makes stone a bad idea, we will tell you, and we would rather do that at the sample stage. Send photographs of the room and the tile you are considering, and we will tell you what it needs.