Every week we receive at least one call from someone who needs to redo a bathroom that was renovated less than two years ago. Sometimes it is an obvious functional problem — a shower that floods the floor, a vanity unit that cannot fully open because it hits the toilet. Other times it is something more subtle yet equally frustrating: a bathroom that looks perfect in photographs but in daily life proves uncomfortable, dark or impossible to keep clean.
The common denominator is always the same: design mistakes made before the building work began. Decisions that seemed inconsequential at the time — “it doesn’t matter where the socket goes,” “we’ll sort the ventilation out later” — and that within a few months reveal their true cost. Because the price of poor design is not paid once: it is paid every day you use that bathroom.
At Azulia we have catalogued the mistakes we see most frequently in the projects that arrive at our studio asking for a second chance. There are seven, and between them they account for the bulk of the renovations that could have been avoided with serious planning.
1. Choosing materials from a photograph without seeing or touching them in person
This is probably the most widespread mistake of the digital age. Instagram and Pinterest have democratised access to inspiration — which is wonderful — but they have also created the illusion that you can know a material by seeing it on screen. And you cannot. Not even close.
A porcelain tile that looks light grey in the catalogue photograph may appear greyish-green under the fluorescent light of your bathroom. A marble that looks uniform in the render has veining that varies from slab to slab, and that variation can be a gift or a disaster depending on the size of your space and the direction of the natural light. Texture — matt, satin, polished, textured — radically alters the perception of colour, and no screen is capable of conveying it.
The solution is simple but requires discipline: before approving any material, you must see it in person, touch it, place it under the light of the space where it will be installed, and compare it with the other materials in the project. In the Castellon area there are manufacturer showrooms that allow exactly that — and a good designer organises these visits as a natural part of the process. We explain this in detail in our article on the complete design process.
Cost of correction: removing a wall or floor finish and reinstalling with a different material starts at 3,000 euros and can exceed 6,000, not counting the new material or the inconvenience.
2. Ignoring storage
A bathroom can be visually spectacular and, at the same time, functionally unbearable. And the most frequent reason is the lack of storage. Shampoo bottles on the shower floor. Hair dryers resting on the basin. Towels piled where they should not be. The visual chaos that destroys any aesthetic intention.
It is an error born of prioritising image over use. And it is understandable: magazine bathrooms do not show the moisturiser bottles, the razors or the cleaning products. But those objects exist in real life, and if the design does not reserve a place for them, they will find one on their own — and it will not be attractive.
Intelligent design integrates storage into the composition: recessed niches in the shower, vanity units with organiser drawers, auxiliary cabinets, shelves concealed behind mirrors. All without sacrificing usable square metres. The difference between a bathroom with well-resolved storage and one without is not apparent in photographs, but it is felt every morning.
Cost of correction: adding storage after the fact — niches that require opening walls, units that do not fit — ranges from 800 to 2,500 euros, plus collateral damage to the already-installed finish.
3. Flat, single-point lighting
A single ceiling fixture. That is the standard lighting in 80% of bathrooms in Spain. And it is, probably, the decision that most impoverishes a space that could be extraordinary.
Flat lighting casts hard shadows beneath the eyes when you look in the mirror, eliminates any sense of depth and turns a carefully designed bathroom into a space that feels like a gym changing room. If you have invested in textured materials — a veined marble, a relief porcelain — flat overhead lighting crushes them visually.
A lighting plan for a premium bathroom includes, at a minimum, three layers: diffuse ambient light (ceiling or perimeter), functional light at the mirror zone (from the sides, never overhead) and accent light to create depth (backlighting, LED strips in niches, low-level points). We unpack this fully in our article on lighting and atmospheres in the bathroom.
Cost of correction: redoing the electrical installation to add light points where none were planned involves chasing into walls that are already tiled, new cabling and, in many cases, patching or replacing damaged finishes. Easily 1,500 to 4,000 euros.
4. Incorrect scale of tapware and sanitary ware
We see this a great deal in apartments in the Ensanche and in neighbourhoods such as Benimaclet or el Cabanyal: bathrooms of 4-5 m2 where a 30 cm rain shower head has been installed that looks like a spaceship landing in a telephone box, or a countertop basin that leaves 15 cm of clearance to the wall opposite.
Scale — the proportional relationship between elements and the space that contains them — is one of the most important principles of design and one of the most ignored. A piece of sanitary ware that looks elegant in the showroom can appear enormous in your bathroom. A wall-mounted tap set that looks spectacular on a two-metre wall can look absurd on a 90 cm partition.
The mistake is almost always made for the same reason: the element is chosen because it is liked in the abstract, without verifying how it relates to the actual dimensions of the space. A professional designer works with scale plans and, when necessary, with 3D renders that allow proportions to be visualised before anything is purchased.
Cost of correction: replacing already-installed sanitary ware or tapware — with their recessed water connections, drains and perforated finishes — can range from 1,200 to 3,500 euros per piece, including restoration of the affected finishes.
5. Failing to plan the ventilation
Valencia. Average relative humidity of 65-70%. Summers where the thermometer does not drop below 25 degrees even at night. If there is one city where bathroom ventilation cannot be left to chance, it is this one.
A bathroom without adequate mechanical ventilation is a breeding ground for mould, condensation and premature degradation of materials. Silicone joints blacken within months. Wood furniture — even treated — begins to swell. Breathable paints stop breathing when saturated with moisture. And a stale smell takes up permanent residence.
The Technical Building Code, in its section HS-3 on indoor air quality, sets minimum ventilation rates for wet rooms. But meeting the regulatory minimum and having ventilation that actually works are two different things. A timed extractor, a mechanical ventilation system connected to the building’s general circuit or, at the very least, an openable window with sufficient section are requirements that a good designer anticipates during the project phase, not when the walls are already tiled.
Cost of correction: installing mechanical ventilation after the fact — with ducting, extractor and possible facade penetration or connection to a shunt — starts at 600 euros in straightforward cases and can exceed 2,000 if building work is needed to route the duct.
6. Forgetting electrical outlets
Hair dryer. Electric razor. Electric toothbrush. Hair straightener. Aroma diffuser. Backlit mirror. The list of devices we use in the bathroom has not stopped growing over the past decade, and many renovated bathrooms still have a single power socket — if they have one that is visible and accessible at all.
The result is a bathroom where the hair dryer competes with the electric toothbrush for the only outlet, where an extension lead crosses the basin and where the integrated-lighting mirror cannot be installed because nobody planned a socket behind it.
Under Spanish electrical regulations (REBT, ITC-BT-27), power outlets in the bathroom must comply with strict protection zones around the bathtub and shower. This limits the possible positions, which makes it even more important to plan them during the design phase, when it is still possible to decide where fittings go without having to break walls. Our renovation calculator includes the electrical installation as a specific line item precisely because it is a point that should not be left to “as we go along.”
Cost of correction: each power outlet added after the fact — with chase, cabling, back box, fitting and finish repair — costs between 200 and 450 euros. If you need three or four additional outlets, the figure quickly approaches 1,500 euros.
7. Copying a design without adapting it to the space
We call it “Pinterest syndrome” and we encounter it with a frequency that invites reflection. A client arrives with the photograph of a spectacular bathroom — terrazzo floor, floor-level shower with linear drain, freestanding bathtub facing a picture window — and wants exactly that in their 60-square-metre flat with a 4.5 m2 bathroom and a window that faces the light well.
The problem is not the aspiration. The problem is the literal translation. That bathroom you admire in the photograph has 12 m2, three-metre ceilings, overhead natural light and a budget that probably triples yours. Copying the elements without adapting the proportions, the lighting, the materials and the layout to the real space is the perfect recipe for disappointment.
A good designer takes that inspiration, extracts the essence — the colour palette, the sense of spaciousness, the relationship between filled and empty — and reinterprets it within the real coordinates of your project. That is the creative work, and it is what justifies design fees. If you want to understand how that process unfolds, we explain it step by step in how our method works.
Cost of correction: variable, but when a copied design does not work in the actual space, the solution usually involves rethinking the layout, which may mean dismantling part of what has been built. Depending on the magnitude of the error, between 2,000 and 8,000 euros.
The real cost of every mistake — the full perspective
If we add up the correction ranges for all seven mistakes, we are talking about between 9,500 and 27,000 euros in potential additional costs. It is a figure that may seem exaggerated, but it is not for those who have had to live through it. Evidently, it is unusual to commit all seven mistakes at once. Two or three is enough to create a serious problem and a budget that has multiplied unnecessarily.
The irony is that avoiding all of these mistakes has a known, contained cost: a professional design project that detects and resolves them before they become fait accompli. That investment — between 10% and 15% of the renovation budget — is, by a long margin, the best insurance policy you can take out for your bathroom. We unpack it in our guide on where not to cut corners in a premium renovation.
Frequently asked questions
Which of these mistakes is the most common in renovations without a designer?
Lack of storage and flat lighting tie as the most frequent mistakes. They are the least visible during the project phase — a plan without niches or a lighting scheme looks “correct” — but the ones that most affect the daily experience. Third in frequency is ventilation, especially in Valencia where the ambient humidity amplifies the problem.
Can I avoid these mistakes by using an online configurator instead of a designer?
A good configurator — like the one we offer at Azulia — helps you explore styles and obtain an initial budget estimate. But it does not replace spatial analysis, a technical site visit or construction coordination. It is an excellent starting point; it is not a substitute for professional design.
How much does a design project that prevents these mistakes cost?
Professional design fees for a premium bathroom range between 10% and 15% of the total renovation budget. For a bathroom with an execution budget of 15,000 euros, that means between 1,500 and 2,250 euros — a fraction of what it would cost to correct any of the mistakes described in this article.
Is it possible to correct a design mistake without redoing everything?
It depends on the mistake. Adding mechanical ventilation or electrical outlets can be done with localised work. Changing a finish that is not working or moving poorly positioned sanitary ware involves a more extensive intervention. In general, the sooner the mistake is detected, the less invasive and less costly the correction will be. If you need an assessment of an already-renovated bathroom, you can consult us at our studio.
The finest bathrooms are not those with the most expensive materials or the most daring designs. They are the ones that work well every day, without friction, without frustration, without unpleasant surprises two years after completion. And that, in our experience, is always the result of good preliminary design — never of improvisation, however much luck one might have. If you want to start your project on the right foot, our studio in Valencia is a good place for the first conversation.