Interiors and renovation in Barcelona, with a project and site supervision
Layout, light, materials and detail — but also structure, the permit and a site supervisor who keeps the builder in check. We do not carry out your works: we make them buildable, payable and finishable. Technical fees from €2,400 + VAT.
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This is a technical practice, not a building firm
A flat in the Eixample that looks lovely in a render and is hard to build is an expensive problem. We come at it from the other side: twenty years running sites, so when we design we know which wall is load-bearing, where the soil stacks run and how much headroom a suspended ceiling eats. That does not take the ambition out of a project. It protects it.
The practical difference lies in the three roles the law separates and almost nobody explains. The proyectista signs the project — for residential use the LOE, the Spanish building act, requires an architect. The director de obra directs how it develops. And the director de la ejecución has one very specific job: «to direct the material execution of the works and to control the construction qualitatively and quantitatively». That third role belongs to an arquitecto técnico or aparejador, a separately regulated profession from the architect: where the architect answers for the design, the arquitecto técnico measures, controls quality on site and certifies what has actually been built. If nobody fills that role, the person measuring and certifying the work done is the builder himself. Which is to say: no control at all.
That is why we own no building firm and take nothing from any of them. We help you ask for comparable tenders against one and the same list of measured items, and then we control the execution on your behalf. If that part is all you need, it can be engaged on its own: it is our execution management.
We do not build your works. We make them buildable, payable and finishable.
Which permit each job needs in Barcelona
It is governed by the municipal by-law on building work, the ORPIMO, which lays down four regimes. Picking the wrong one is the quickest way to have your site stopped. This is what each case takes, with the article.
| Assabentat · minor works type IIIInterior work that does not alter the layout, the structure or the façade, in a building that is neither listed nor protected (art. 3.5.a). An assabentat is a bare notice: no documentation, you start the next day and you have 3 months to carry it out — painting, changing floor finishes, replacing sanitaryware where it stands, changing the kitchen units | Nothing to file |
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| Comunicat d'obres · minor works type IIThe typical full renovation of a flat: interior work that alters the layout without affecting the structure, isolated work on the structure, work on façades or light wells and the fitting of soil stacks (art. 3.4). A comunicat d'obres is a works notification you file yourself; you start the day after filing, with the documentation verified and the ICIO — the municipal tax on construction work — paid | Project + IIT |
| Comunicat d'obres · minor works type IWork partially affecting the structure, an internal lift, buildings of level D or in a protected setting, and — this one surprises people — renovating two or more flats in the same building (art. 3.3). The Ajuntament, the city council, has 1 month in which to object | 1 month's wait |
| Llicència d'obra majorOverall intervention in the foundations or the structure, change of main use, creating new dwellings, an external lift and work on the façade of listed buildings (art. 3.2). Decided in 2 months, or 3 where the fire brigade or the heritage department report | 2–3 months |
| The informe d'idoneïtat tècnicaCompulsory in type I and type II comunicats. It is issued at your expense by an entitat col·laboradora — an approved private body, not the council — and verifies that the project is complete, sufficient and fit for purpose and that it complies with the CTE, the Spanish building code, plus fire, accessibility, habitability and eco-efficiency. A weak project does not slip through: it is stopped here | Compulsory |
| The rule most often brokenArt. 6.5: works of different classes that make up a single operation go into a single project and follow the most demanding regime. Meaning a full renovation cannot be sliced into three assabentats. It is the trap that stops the most sites | No slicing it up |
When a project is required, and how much of the CTE reaches you
Two layers apply at once. The national one: the LOE requires a project for any intervention in an existing building that alters its architectural configuration. And the municipal one, which goes further: the Barcelona by-law requires a project signed by a competent technician, with a specification, drawings and a budget for the mere interior alteration that changes the layout without touching the structure. The working rule: the moment you move a partition wall you need a project, a technician who takes responsibility for it, an IIT and a health and safety study.
A great deal of confusion circulates about the CTE, so here are the two facts that save arguments. The DB-HR, the sound section, expressly excludes renovation work in existing buildings from its scope, other than full refurbishment: an interior renovation, however complete, does not drag the DB-HR in with it — whether you want to solve sound insulation properly is another matter, and it almost always pays to. And the DB-HE, on energy, only bites at particular thresholds: renovations that jointly renew the heating plant and more than 25 % of the envelope, changes of use above 50 m², or extensions of more than 10 % with more than 50 m².
What always applies is not making things worse: in existing buildings the pre-existing conditions relating to the basic requirements may not be reduced. And there is one declaration the project author signs that is no formality: whether or not the intervention acts on the existing structure. Ten years of liability hang on that signature, and it should not be signed by whoever also carries out the work. If the structure has to be touched, we calculate and justify it ourselves.
The numbers that decide whether your drawing is legal
This is what turns a handsome interiors drawing into a buildable project, and it is set by Decret 141/2012, the Catalan habitability regulations. Which annex applies depends on the type of work: a complete redistribution without changing the floor area goes under Annex 2 with exceptions, and dividing one dwelling into two jumps to Annex 1.
| Clear headroom2.50 m in general and 2.20 m in bathrooms, kitchens and circulation. 2.30 m is allowed in the living room, dining room and bedrooms only where services pass through, and affecting at most 20 % of the room. A continuous suspended ceiling at 2.30 m does not fit that exception | 2.50 · 2.20 m |
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| BedroomsMinimum 6 m², and in dwellings of three bedrooms or more at least one must take a square of 2.60 m a side. In a complete redistribution of an old flat Annex 2 governs, but the bedrooms still have to reach 6 m², and any new bedroom or bathroom already complies with Annex 1 | 6 m² |
| Ventilation and daylightNatural and direct from outside, with openings of an area not less than 1/8 of the usable floor area of the room. An internal bedroom with no window does not comply, however well it is ventilated mechanically | 1/8 |
| BathroomsWith 0 to 3 bedrooms, one WC, one basin and a shower or bath; with 4 bedrooms or more, two WCs and two basins. And the bathroom cannot be the only way through to the other rooms | 1 · 2 |
| Open kitchenIf it is opened into the living-dining room, the open vertical area between the two spaces is not less than 3.50 m² — 1.40 m² under Annex 2, with a 14 m² kitchen-living room. An opening 2 m by 1.5 m does not get there. And mechanical extraction over the hob, ducted up to roof level | 3.50 m² |
| Corridors and doorsA practicable dwelling requires 1.00 m on the routes connecting the entrance with the practicable spaces, and a clear door opening of 0.80 m. Plenty of interiors drawings show 0.80 m corridors and 0.72 m doors | 1.00 · 0.80 m |
| The escape valveArt. 6 allows requirements to be waived with reasons — no worsening, proportionality, non-intervention, incompatibility and improvement — but never below Annex 2, and justifying it requirement by requirement in a specific part of the project. Whoever does not write it down has no defence | It has to be written |
What is yours, what belongs to everyone, and by what majority
Every block of flats in Spain is run by a comunidad de propietarios, the owners' association every owner belongs to by law, which meets in general meeting — the junta — and votes on anything that touches the building. Under the Catalan civil code the common elements are «the structures, the façades, the roofs, the entrance halls, the staircases and the lifts» and, in general, the installations serving the private units. Translated to your flat: the structure, the façade — including its windows, in so far as they define the external appearance — and the soil stacks are not yours, even where they run inside your home. A terrace for your exclusive use is still a common element.
Two duties almost nobody complies with. The first: anyone about to carry out work in his own unit must notify the chair or the managing agent beforehand, always, however innocent the work. It is not a courtesy, it is art. 553-36.3. The second: if the work alters common elements, a resolution of the junta is needed, and the legal test is not «causing a nuisance», it is not reducing the soundness or the accessibility of the building and not altering its configuration or external appearance.
And a time limit that explains a good many irregular jobs: the association is taken to have consented if the work was obvious, did not reduce soundness, did not occupy common elements and nobody objected within four years of its completion. It cuts both ways: it protects whoever renovated long ago, and it lands on whoever buys a flat with inherited works.
What gets voted on, and with how many votes
This is the part that decides whether your renovation happens this year or next. The majorities are fixed by law and very few people quote them. Each comes with its article of book five of the Catalan civil code.
| Simple majorityRemoving architectural barriers and installing a lift, even where it affects the structure or the external configuration; and improvements required for habitability, accessibility, safety or energy or water efficiency (arts. 553-25.2.a and b). Also electric vehicle charging points and individual metering | 553-25.2 |
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| Four fifthsAny physical alteration affecting the structure or the external configuration that does not fall within the exceptions above (art. 553-26.2.b). It is the majority needed, for instance, to change the windows for others of a different pattern or colour | 553-26.2 |
| UnanimityAltering the ownership shares, detaching an annex, and tying the exclusive use of light wells, terraces or roofs to a private unit (art. 553-26.1) | 553-26.1 |
| The owners who do not attendThey count in favour if they do not object in writing within one month of being notified of the resolution. It is the practical way to carry a four-fifths resolution in a building full of absent neighbours | 1 month |
| Soil stacks and drainageThey are a common installation: moving or replacing them takes a resolution of the junta and, in Barcelona, a type II comunicat d'obres. Moving a WC out of its original wet zone almost always ends up touching a stack or producing too shallow a fall | Junta + comunicat |
| Going through the neighbour's flatPrivate units are subject to the restrictions strictly needed for conservation work on the common ones, where there is no other way or it would be disproportionately expensive, and whoever benefits must make good the damage (art. 553-39) | Compulsory easement |
How a builder is kept under control
Nobody rings up frightened of the design. They ring frightened of the process: that the price will climb, that it will drag on, that the site will be stopped, that the builder will vanish half way through. This is what we do so that it does not happen, and all of it has a legal anchor. A genuinely fixed price: the Código Civil, the Spanish civil code, says that whoever contracts for a lump sum «on the basis of an agreed drawing» cannot claim an increase in price unless there has been a change to the drawing and the owner has authorised it. Without defined drawings, «fixed» is a figure with nothing behind it. That is why the budget is set out as measured items with unit prices, and every variation is documented as a change order before it is carried out.
Interim certificates: a periodic valuation of the work actually carried out, against the same list of items and signed by the director de la ejecución. You never pay ahead of the work done — and take care, because paying for part of it can be read as approving and accepting it. Retentions: a percentage of each certificate, released in two tranches, on handover and at the end of the guarantee on finishes, which the law sets at one year. Damages for delay: an amount per day, with a cap and defined grounds for extension; with no firm completion date there can be no penalty at all.
And the end, where most people come unstuck. Handover is recorded in a certificate signed by the client and the builder, with the final cost, the reservations and the time allowed to put them right. Unless otherwise agreed, if 30 days pass from completion without your stating reservations or a reasoned rejection in writing, the works are deemed to have been accepted — and from there the guarantees run: 10 years for structural defects, 3 for those breaching habitability and 1 for defects in the finishes.
Say nothing for 30 days and you have accepted the works. And the guarantee clock is already running.
What the works cost, per m² and by type
These are orders of magnitude for the Barcelona market as at August 2026, so that you can tell whether the quote in front of you is reasonable. They are not a quotation and not official statistics. And an important warning: this is the cost of the works, which is paid to the builder. Our fees are a separate matter and they are further down.
| Full renovation · medium qualityThe band most jobs fall into. An 85 m² flat in the Eixample usually comes out between €40,000 and €60,000 | €450–750/m² |
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| Full renovation · high qualityBespoke joinery, air conditioning, home automation, special finishes. Above €1,200/m² it is no longer the m² that decides, it is the detail | €800–1,200/m² |
| Partial renovation, layout untouchedFloor finishes, painting, isolated services. This is the one that can go by assabentat, which also makes it the cheapest to get through the council | €250–400/m² |
| A complete bathroomA bathroom of 4 to 6 m² to medium standards, stripping out the finishes. Leaving the wall tiling in place comes to less | €3,000–4,500 |
| A complete kitchenA kitchen of 7 to 10 m², including units and appliances, which are almost 40 % of the item. With no building work, considerably less | €6,000–10,000 |
| What every quote forgetsICIO, council fees, the waste deposit and the IIT. The comparison sites put «permits» at around €1,200 on a 100 m² renovation, and that figure does not include the project, site supervision, execution management or health and safety coordination. That is where the budget falls short | Separate |
From the first visit to the keys, honestly
When somebody announces «8 to 12 weeks», they are talking about the works, not about the job. Everything before them is missing: viability, outline design, project, IIT, the council procedure and appointing the builder. Added up without cheating, a job done properly runs to 5 to 8 months from the first visit to handover if it goes by type II comunicat, and 8 to 12 months if a llicència d'obra major is needed.
The administrative timescales are public and do not depend on us. The assabentat and the type II comunicat let you start the next day, with the documentation verified and the ICIO paid. Type I means waiting a month in case the Ajuntament objects. A major works licence is decided in 2 months, or 3 with a fire brigade or heritage report. And once granted, you have to start within a year and finish within three.
What does depend on us is that the calendar holds. Two warnings: any change during minor works requires a fresh notification with a fresh IIT, so decisions are closed before work starts; and if the building dates from the fifties to the seventies, the floor structure has to be looked at before anything is priced, because a joist made with high-alumina cement turns a layout renovation into a structural intervention.
Interiors
Homes, offices and retail space in Barcelona.
How it works, stage by stage
Viability · 1-2 weeks
Visit, measured survey of what is actually there, check of whether the building is listed, of the regime that applies to it and of the state of the cèdula d'habitabilitat and the ITE. Before anything is designed.
Outline design and interiors · 2-4 weeks
Layout, light and materials, checked against habitability from the first sketch, and a reference budget so that you decide with a figure in front of you.
Construction project · 3-5 weeks
Specification, drawings, measured items and a priced schedule, health and safety, and the habitability and CTE justifications the IIT is going to look at.
Visat, IIT and filing · 1-3 weeks plus the wait
The project stamped by the professional body — the visat — filing of the comunicat or the licence application, ICIO and deposits. Type II starts the next day; type I waits a month; major works, 2 to 3 months.
Appointing the builder · 2-4 weeks
Comparable tenders against the same list of items, a contract with a payment schedule, retention and damages for delay. The client chooses, not us.
Works and certificates · 10-16 weeks
Visits, control of execution and quality, monthly certification of work actually carried out, and written change orders if anything moves.
Handover and closing
Handover certificate with or without reservations, final works certificate, the record documentation and the cèdula where it applies. From there the guarantees run.
What clients ask us most
Do I need a permit to renovate a flat in Barcelona?
Almost always something. If you do not alter the layout, the structure or the façade and the building is neither listed nor protected, an assabentat is enough — no documentation, and you start the next day. The moment you touch the layout it becomes a type II comunicat d'obres, which requires a signed project, a declaration by the technician, health and safety and an informe d'idoneïtat tècnica. We check which one applies before anything starts, at no charge.
I want to knock down a partition wall to open the kitchen into the living room. What do I need?
You are altering the layout, so a type II comunicat d'obres with a project and an IIT. And before that, two checks: that the wall is not load-bearing — if it is, you are into structure, which is a common element and needs a resolution of the junta — and that the open kitchen meets the minimum open vertical area with the living room, which at the higher standard is 3.50 m².
Can I divide my flat into two?
That is a llicència d'obra major, because it creates new dwellings, and afterwards there is a first-occupation notification. On habitability you jump to Annex 1 with exceptions: a minimum height of 2.40 m instead of 2.50 m, and one of the two dwellings may be treated as already in use if it meets Annex 2, but with 36 m² of usable floor area as a minimum. It works more often than people think, but it has to be studied before you buy anything.
Can I move the bathroom?
Technically yes, with a project. The problem is not the bathroom, it is the soil stack: if it has to be touched or diverted it is a common installation and you need a resolution of the junta, as well as the comunicat. And two habitability conditions that get forgotten: the bathroom cannot be the only way through to the other rooms, and it needs ventilation to the outside.
I am putting in a suspended ceiling and underfloor heating. Will I run out of height?
It is the commonest technical question and the answer has a number in it: 2.50 m clear in general, and 2.20 m in bathrooms, kitchens and circulation. 2.30 m is allowed in the living room, dining room and bedrooms, but only where services pass through and affecting at most 20 % of the floor area of the room. A continuous suspended ceiling dropped to 2.30 m does not fit that exception.
Do I have to tell the owners' association?
Yes, always. Anyone about to carry out work in his own unit must notify the chair or the managing agent beforehand. And if the work alters common elements — structure, façade, soil stacks, roof — it needs a resolution of the junta by whichever majority applies. We draft the notification, and the report for the meeting where one is called for.
Can I change my windows for different ones?
If the pattern, the colour or the material changes, you are altering the external appearance of a common element, and that takes four fifths of the owners and of the ownership shares. With one very useful exception: if the replacement is an improvement required for habitability, accessibility, safety or energy efficiency, a simple majority is enough. How the item on the agenda is worded is no detail: it changes the majority you need.
I was given a fixed price and now they are asking for more money. Can I refuse?
If it was a lump sum on the basis of an agreed drawing, the contractor cannot claim an increase in price even if wages or materials go up; he can only do so if there was a change to the drawing that produces more work and you authorised it. That is why we insist so much on a project with defined drawings and on written change orders: without them, «fixed» is not fixed.
What does it cost to renovate a flat in Barcelona?
In building work, between €450 and €750/m² to medium standards and €800 to €1,200/m² at the high end; the breakdown is in the table on this page. That money goes to the builder. Our technical fees are separate and they are published below: a project from €2,400, and the full package with the permit and site supervision as a percentage of the PEM — the presupuesto de ejecución material, the bare cost of the construction work itself, before the builder's overheads, profit and VAT. We say it that plainly because this is where the confusion is worst. Prices exclude VAT: in Spain IVA is 21 % and professional fees are always quoted without it.
How long does it really take?
From the first visit to the keys, 5 to 8 months with a type II comunicat and 8 to 12 if a major works licence is needed. The building work itself is 10 to 16 weeks; the rest is project, IIT, council procedure and appointing the builder. We say so in advance even though it sounds long: the realistic calendar is the first thing that breaks when somebody promises eight weeks.
Can you come in for the site supervision only?
Yes, we also work with another practice's project. We start by reviewing the project and the state of the works and telling you frankly what we have found: sometimes the best news is that the project is sound and all that is missing is somebody to measure what gets built. That is the execution management engagement.
I have bought an old flat and want to renovate it. Where do I start?
Ideally before buying, with a pre-purchase survey. If you have already signed, we start by finding out what is there: structure, services, and if the building dates from 1950 to 1975, ruling out high-alumina cement. And if the property is a commercial unit, the first thing is not the interior design but checking the viability of the change of use to residential, which turns on heights, ventilation and planning.
Renovation on the horizon?
Tell us about the flat and what you want to do. We will tell you which permit applies, what it means technically and what budget you really need — the builder's and ours, kept apart.