Bear in mind, if you are not already aware, that undertaking ANY work to your own property requires a permit/licence from the local Town Hall - Ajuntamiento. There will be a charge for making the application and then a charge for the permit, based on a value per square metre, costs vary depending upon the Ajuntamiento. If it is ‘serious’ work, ie even removing non-load bearing internal walls, then you will be required to present architect’s drawings etc.
If you are caught doing work without a licence, you may be heavily fined.