As I understand it, after lots of research and advise from banks lawyers etc., Community insurance covers only community areas. In our apartment block that seems to mean all the exterior walls of the building, corridors etc., and I am now told that it also covers the 'outside' of the apartment doors which are in the said corridors, and the windows, if they are on exterior walls.....but only for forced entry ( and you must contact the insurers before you attempt to repair ). Water pipes are covered if they are in community walls but those in the apartment are not. This whole community thing is complex and so far we have not got our community insurers to comit...except for the policy which is quite difficult to understand. Having looked at many insurance people for community insurance, it seems, in Spain, they are all similar ( read ambiguous!)
So, in short, you do need your own building insurance because it is unlikely that the community insurence will cover you. I have an apointment with my bank which is where I have my personal building insurance from next Wednesday and if I learn anything more about Community and or personal building insurance I will post.
Trouble is, with ANY insurance, you only find out how good it is ( or bad!) when it's too late.