In Spain, it is not usually possible to give exact answers to general property planning questions such as yours.
Why? Because so much depends on fairly autonomous local councils. They may, or may not, be enforcing local regulations. They may also decide to enforce in the future those regulations that they are not currently enforcing.
Local builders and neighbours will probably tell you not to worry and just get on with it. And they maybe right – or not.
It all depends on how much risk you are happy to shoulder. If you want to be as clear as possible about what is allowed then speak to the local council and/or an architect.
However, if you are happy to take a flyer then just go ahead – but don’t complain afterwards if you are fined or find yourself submerged in a bureaucratic jungle.
Personally, as an uninformed foreigner, I would play safe and speak to the right people first.
Good luck. 🙂