The bathroom is the smallest room in the house and the most expensive per square metre. The reason is not the price of tiles but the number of systems stacked on top of one another in a confined space. In this guide we approach bathroom renovation through three questions: in what order the work is done, where the money actually goes, and what stretches the programme.
The bathroom is the smallest room in the house and the most expensive per square metre. The reason is usually not what people assume — the price of the tiles or the taps. The reason is that six separate systems are stacked on top of one another in three to five square metres: hot and cold supply, waste, ventilation, electrics, heating, and the waterproofing that covers all of them. No other room in the house carries that density.
The practical consequence is this: most mistakes in a bathroom are not irreversible, but they are reversed expensively. A badly chosen floor in the living room can be lifted and replaced; waterproofing done badly in a bathroom is, by the time anyone notices, already on the ceiling of the flat below, and putting it right means stripping out a newly finished bathroom.
In this guide we approach bathroom renovation through three questions: in what order the work is done, where the money actually goes, and what stretches the programme. If you are considering a whole-home refurbishment, we covered the subject as a whole in our article on the complete home renovation process; here we go down into a single wet room.
1. The order of decisions comes before the order of works
The most common cause of delay in a bathroom renovation is not slow tradesmen; it is taking the decision after the work. The reason is simple: almost every product in a bathroom determines a piece of construction that precedes it.
Whether you use a shower tray or a level-access shower determines the screed depth and the type of drain. If you choose a wall-hung WC you need a wall for the concealed cistern behind it, and that wall changes the clear dimension of the room by several centimetres. The type of basin dictates the height of the supply and waste connections. If a heated towel rail is going in, the pipework has to be run for it. None of this can be changed once the tiles are on.
For that reason, in a well-run bathroom renovation the product selection is finished before the strip-out begins. A decision that is late on paper is cheap; the same decision taken after the walls are built comes back as demolition, repair and rebuilding. The practical test is this: before strip-out starts, the WC, basin, shower system, brassware and tile dimensions should be known — at the very least their types and sizes should be fixed.
2. The correct sequence of works
A bathroom is one of the jobs that punishes you hardest when the sequence is broken. A sound sequence runs roughly as follows:
Strip-out and waste removal. The old tiles, sanitaryware and, where present, the old screed come out. The one critical thing here is not damaging a wall that was assumed to be non-structural, or the existing services in the floor. Before breaking out, you need to know where the existing supply and waste runs go.
First-fix plumbing. Supply and waste are run to suit the new layout. The falls on the waste are set at this stage; this is the item that is all but impossible to correct later. Ventilation ducting and electrical first fix are also positioned now.
Pressure test. Before anything is closed up, the system is left under pressure and checked for leaks. This is the easiest step to skip and the most expensive one to have skipped.
Wall works. The cistern wall, niches and any partitions are built.
Waterproofing. Floors and wetted wall surfaces are coated with a liquid-applied membrane; corners and the area around the drain are reinforced with tape and collars.
Screed. The floor is levelled with a fall towards the drain.
Tiling. Wall and floor finishes go on, followed by grouting.
Sanitaryware, furniture and brassware installation.
Silicone, lighting, accessories and cleaning.
The most critical transition in this sequence is the point between waterproofing and tiling. If tiling starts without respecting the membrane's curing time, the material will not perform however good it is. That is also exactly the period that gets squeezed most often on site.
3. Waterproofing: the one item that is not negotiable
There are plenty of items in a bathroom renovation that can be trimmed. Tiles can come from a lower range, brassware from a more economical series, the furniture can be simplified. Waterproofing is not one of them, and the reason is not technical but arithmetical: it is a small percentage of the total budget, but when it fails it takes the entire renovated bathroom with it.
A common misconception is that tiles and grout are waterproof and therefore do the job of a membrane. Tile is waterproof; a tiled surface is not. Water finds its way through the grout, the internal corners, the area around the drain and the points where the silicone has aged. The job of the membrane is to catch that water before it reaches the structure and direct it back to the drain.
Correct application has a few markers. The membrane should run not only across the floor but up the wall to the height that gets wet — in the shower area that usually means close to ceiling level. Floor-to-wall junctions, internal corners and pipe penetrations are the weakest points and need tape and collars. Liquid membranes go on in the number of coats the manufacturer specifies, respecting the drying time between coats. Finally the floor fall really does have to run to the drain; a floor where water sits in a corner keeps the membrane under constant and unnecessary load.
The same logic applies to sound: in bathrooms next to bedrooms in particular, pipe noise becomes a complaint that is hard to resolve afterwards. We covered that subject in detail in our article on acoustic insulation in interiors.
4. Where the money goes
In a bathroom renovation the budget does not go where you expect. People tend to build a budget around the things they can see — tiles, taps, mirrors, furniture. In most projects, though, the bulk of the spend is labour and the work you never see again.
Broadly, the total is shared between: strip-out and waste removal; plumbing materials and labour; waterproofing; screed; tile materials; tiling labour; sanitaryware and brassware; bathroom furniture; electrics and lighting; and the coordination that keeps all of it in order. Within these, the two easiest to move by changing product are tiles and furniture; the labour items do not come down through negotiation, only by reducing scope.
Three things inflate the budget more than anything else: moving the position of services (shifting the WC or the shower means rebuilding the waste run), large-format tiles (which cost more in labour and substrate preparation than in material), and decisions that change after work has started. What these three share is that none of them is visible at quotation stage.
For quotes to be comparable, therefore, the scope behind them has to be the same. We set out the logic of pricing, and why quotations differ so widely, in our article on how interior design fees are determined.
5. What determines the timescale
A bathroom of standard dimensions, when the work runs without interruption, usually takes between two and four weeks. The number of days actually worked within that period is in fact small; what sets the duration is waiting time.
There are three waiting items and none of them can be compressed: the drying of the membrane between coats and at the end, the curing of the screed, and the curing of grout and silicone. Ignore them and the job finishes early, but the problems surface a few months later.
What really stretches the programme lies elsewhere: material supply. A tile that turns out to be out of stock, the lead time on a made-to-measure vanity unit or a delayed imported tap will stop the site for days — and that stoppage always happens mid-job, at the worst possible moment. Second come changes of mind; every new decision taken on site rebuilds the work behind it.
In apartment buildings there is a third constraint: working hours and building rules. Noisy breaking-out work is restricted to certain hours in most buildings, and permission may be needed from the management for lift use and waste removal. If these are not written into the programme at the outset, the duration extends by itself.
6. What actually works in a small bathroom
The most common answer to a small bathroom is pale tiles and a large mirror. Those help, but the decisions that really change the perception are different ones.
The most effective is an uninterrupted floor: a level-access shower finished in the same material as the rest of the floor makes the room look larger than it is because nothing divides it. The second is wall-hung sanitaryware and furniture; seeing the floor run on beneath them both opens the room up and makes cleaning easier. The third is the use of niches: a recessed shelf removes the need for anything that protrudes.
There is also a decision that does not work in a small bathroom: increasing the number of glass screens or walls that divide the space. Every division fragments a small volume further. In the same way very small format tiles crowd the surface visually by multiplying the grout lines.
7. Full renovation or refresh in place
Not every bathroom problem calls for a full renovation. If the tiles are sound, the plumbing works and there is no sign of damp in the floor, then renewing the sanitaryware and brassware, changing the furniture, reworking the lighting and renewing grout and silicone can produce a marked difference on a far smaller budget.
A full renovation becomes unavoidable in these cases: damp or staining on the floor below or on an adjoining wall, water standing on the floor, frequent blockages or leaks, a layout that simply does not work, or plumbing that has reached the end of its life because of the age of the building. In those situations a surface refresh does not solve the problem and amounts to spending money on work that will be stripped out again within a few years.
Five common mistakes
1. Leaving product selection until after the strip-out. Every product in a bathroom determines the construction that precedes it. A late choice comes back as a broken wall.
2. Expecting the tiles to do the waterproofing. Tile is waterproof; a tiled surface is not. Water gets through grout and corners — that is exactly what the membrane is for.
3. Cutting the drying times short. A job that finishes early is a problem that appears a few months later. These periods are not open to negotiation.
4. Ignoring ventilation. If moisture is not extracted, even the best waterproofing will not prevent mould and odour; a window is not always enough.
5. Moving services for aesthetic reasons. Shifting the WC or shower a few centimetres looks harmless; because the waste run and its falls have to be rebuilt, it is the quietest cause of budget inflation there is.
Frequently Asked Questions
How long does a bathroom renovation take?
For a bathroom of standard dimensions, with materials on hand and no changes of mind, the answer is usually between two and four weeks. A significant part of that is not active work but waiting for the membrane and the screed to dry. What really extends the programme is delays in material supply and decisions that change once work is under way.
Where does most of the money go in a bathroom renovation?
Into labour and the work you never see again rather than into visible products: plumbing, waterproofing, screed and tiling labour. On the material side, tiles and furniture are the two items most easily flexed to suit a budget. The three things that inflate a budget most are moving the position of services, choosing large-format tiles and changing decisions after work has started.
Can a bathroom be renewed without removing the tiles?
Yes, if conditions allow. Where the existing tiling is sound, the plumbing works and there is no sign of damp, renewing the sanitaryware, brassware, furniture, lighting, grout and silicone can produce a marked result. But if there is staining in the flat below, water standing on the floor or recurrent blockages, a surface refresh only postpones the problem.
Is waterproofing really essential?
It is. Its share of the total budget is small, but when it fails it takes the whole renovated bathroom with it. Tile and grout alone do not act as a membrane; water gets in through corners, around the drain and through aged silicone. The membrane's job is to direct the water that reaches beneath the tiles back to the drain before it enters the structure.
Do you need permission to renovate a bathroom in an apartment?
For a refurbishment that stays within your own unit and does not touch the structure or shared services, formal consent is usually not required; but you do need to inform the building management and agree working hours, lift use and waste removal. If a structural wall is involved, a change to a shared riser, or relocating the wet room itself, the position changes and a technical assessment is essential.
Let us talk about your bathroom project
At Kaya + Partners we design not just the visible surface of a bathroom but the plumbing and waterproofing behind it: layout, product selection, construction detailing, sequence of works and site management all run from one place. Among the interior design practices working in Ankara, what sets us apart is that design and delivery sit within the same team. For wet rooms and refurbishment in commercial premises, see our Ankara commercial refurbishment page.
To discuss your project, get in touch with us; you can review our completed work on our projects page.