Just like anywhere in the world, Catalunya has its rules about what you can and can't do.  But the dozens of estate agents in Tortosa all selling various sorts of properties succesfully, must be a good indicator of the fact that people are quite happily buying and selling in the area...from small fincas with no building whatsoever, to villas to flats and apartments.

Don't be put off...its a beautilful area....ask lots of questions...try to go and see properties with different agents, and get a solicitor to go through the paperwork before you buy.

Liz