New construction and major rehabilitation: one licence, different risks

The same licence does not mean the same process

Both construction from scratch and major rehabilitation of an existing building in Barcelona usually follow the same regime: the licencia de obres majors, which applies to genuinely new construction and extensive structural works. Lighter regimes, such as comunicat immediat, comunicat diferit and assabentat, are intended for less substantial interventions and are not suitable here. See our article on types of works permits. But a shared licensing route does not make the projects equivalent in substance. That difference, rather than the fact that both fall under the more demanding licensing regime, is the subject of this article.

New construction: a blank slate and the current code

An obra nueva project starts with an empty plot and is designed as a fully bespoke technical project complying with current standards in their entirety, without limitations inherited from an old structure. After completion, a declaration of new construction (declaración de obra nueva) must be registered. This separate legal step completes the process of formally recording the constructed property. A project built from scratch has no building history to unravel first: it has a plot and a design brief.

Rehabilitation: working with what actually exists

Major rehabilitation must work within the actual condition of the existing structure. That condition first needs to be established through a technical survey before designing the intervention. If the building is listed as heritage, conservation restrictions also apply; see our article on heritage protection in the historic centre. Even without protected status, rehabilitation regularly encounters issues absent from new construction: hidden structural defects, historic materials, and discrepancies between the real building and its original documentation. Drawings inherited from previous owners often differ from what a survey reveals. Time and money for investigating this also need to be allowed for in advance.

Why the distinction matters for two DNPI strategies

For a development strategy based on new construction, the key risks concern the accuracy of the technical design and the time required to secure approvals from scratch. For a residential flipping strategy involving existing historic stock, the key risk is uncertainty about the building’s actual condition. A good design does not eliminate that uncertainty: only a thorough survey reveals it. These are two different risk profiles under formally identical licence terminology. Treating them as one process is a planning mistake.

Practical implications

With new construction, budgets and schedules are more predictable because there are fewer variables: the plot is clear and the design is self-contained. With rehabilitation, a contingency must be set aside deliberately and in advance, rather than as a token budget line. The nature of work on an existing structure means some risks only become visible as the works proceed.