Is it dangerous to transform the balcony into a bathroom with a bathtub?

There are dangers, including two kinds of dangers. First, the balcony bearing capacity is dangerous after the bathtub is filled with water; Two, the relevant national property management laws and regulations prohibit the change of housing structure. So the property management department will intervene. If you have completed the renovation, as long as you bring a lawsuit to the court, the property management department will be in danger of being forcibly removed. For the above reasons, it is best not to transform the outer balcony into a bathroom to avoid unnecessary trouble.

You also said, "The previous owner changed a bathroom, so I want to expand and add a bathtub." Even so, it is still not appropriate to "expand capacity" and transform the outer balcony into a bathroom. The reason is that you will "face two dangers" as mentioned above. Only with the written consent of the property management can the renovation be carried out.

The above opinions are for your reference.