Short answer: what the difference is
The comunicat diferit (deferred-effect notice) is an intermediate regime between the comunicat immediat and a major-works licence. You file documents with the ajuntament that include a technical section signed by a professional, and you may only start once the period during which the council can review and object has passed. With the immediate notice, you can start as soon as it is filed.
Which regime your project needs is decided by the technician under the municipal ordinance for your specific address. Lists of works and timescales change, so check any figure on the council’s e-office at the time of filing.
Which works usually fall under it
Broadly, it covers work more substantial than new finishes but without touching the structure or changing the building’s volume. The typical case is reconfiguring a flat: removing and building partitions, moving the kitchen or bathroom with new drainage runs, without touching load-bearing walls or floor slabs.
The line is drawn at the structure. Replacing tiles and sanitaryware in the same positions usually fits the immediate notice. Removing a load-bearing wall or cutting an opening in it means a major-works licence. We explain how to classify your project in our guide to minor versus major works.
What gets filed
The core of the file is technical documentation signed by a competent professional: a description of the works, drawings of the existing and proposed layout, and a budget. It comes with a responsible declaration, the applicant’s and property details, community consent where required and construction-waste paperwork. Fees and the construction tax are paid; the council confirms the amounts.
We cover the full document list for each procedure in a separate guide, and who may sign the project in another. What matters here: the documents must describe exactly what will be built.
The waiting period and how to use it
While the review period runs, strip-out cannot begin. That time is not wasted, though. It is the slot for everything that has to happen before the works anyway: signing the contract, approving material samples, ordering windows, kitchen and slow-to-make furniture, agreeing noisy-work hours and lift use with the property manager.
A well-planned renovation starts on the day the period ends, with materials already on order. A poorly planned one starts on the same day, but the crew spends its first weeks waiting for deliveries.
What can go wrong
The council may request corrections or extra documents. In practice the clock moves until you reply. The usual reasons are an incomplete file, discrepancies between drawings and written description, or missing community consent where it was needed.
The second problem appears on site. If during the works someone decides to move another partition or the bathroom and the documents stay as they were, the works no longer match what was filed. After an inspection or a neighbour’s complaint, that becomes your problem. Any layout change is checked against the filed documents first.
Example: a flat in the Eixample
In an Eixample flat, the owners want to open the kitchen to the living room and add a second bathroom. On paper, a typical comunicat diferit case. But in Eixample buildings some interior walls are load-bearing, and if the wall between kitchen and living room is one of them, the project moves to a major-works licence with structural calculations. Find out before filing, with the technician on site, not after the wall is opened.
A practical rule for flats like these: until the technician has confirmed the regime, do not give the crew a start date, do not book furniture removal for a specific day and do not sign a temporary rental without a margin. Moving from one regime to the other changes the paperwork and also the time before work can start, so plan family life around the slower scenario.
Next step
Send us the floor plan and a description of what you want to change. Together with the technician we will work out the regime, prepare the file so that what is filed matches what gets built, and use the waiting period for orders. We reply within an hour, in Spanish and Russian.