Changing a building's use: what to consider before you invest

Offices that become homes, homes that become a residence, a school that becomes a hotel. Changing a building’s use is the most direct way to reposition an asset: the same property, with a different use, can be worth far more. But every use has its own rules, and the most expensive mistake is discovering them after buying.

These are the six questions we always answer before a client invests.

1. Does planning allow the new use?

This is the question that decides whether there is a deal. The plot’s zoning sets which uses are permitted and on which floors. In Barcelona there are also special plans that restrict some uses by neighbourhood, such as tourist accommodation, and specific rules for residences, public facilities and activities open to the public.

It is not enough for the use to be allowed in the area: it has to be checked for that specific plot, with its volume and current status.

2. What do the rules for the new use require?

Each use brings its own regulations: habitability for homes, sector rules for hotels or residences, accessibility and fire safety for any use open to the public. When the use changes, the building must comply with the rules for the new use, not the old one.

This is where the costs you do not see on a viewing appear: a lift that must be added, a stair that must be protected, light wells that do not provide the ventilation required.

3. Can the structure take the new use?

Imposed loads change. An office, a residence, a gym or a library do not load a building the same way. You need to check whether the existing structure can take the new use or needs strengthening, and at what cost.

4. Is there room for the services?

A change of use almost always means replacing all building services: HVAC, ventilation, drainage, electrics, fire protection. The key question is not how much they cost but whether there is room to route them: risers, ceiling voids, roof space for plant.

5. How long will the permit take?

The permit timeline is part of the deal’s financing cost. It depends on the type of works, the district and whether the building is listed, in which case a heritage report is added. A well-prepared pre-consultation reduces uncertainty and avoids requests for information that hold up an application for months.

6. Do the numbers work?

With all of the above you can answer the only question that matters: does the end value justify the purchase price plus the cost of transformation? That takes a budget range, a realistic timeline and product scenarios: how many units, what size and what use.

An example

At IESE’s Building L, a listed 1910 building, the change of use to offices took usable area from 500 to 743 m² and capacity from 20 to 50 people, doubling annual rent. Feasibility was confirmed before design began, with a favourable heritage report.

In short

A change of use pays off when it is decided on data: planning, regulations, structure, services, timeline and numbers. At DTRES we answer these six questions in the feasibility phase, before you commit, and then take care of design, permits, construction and FF&E through to handover.