Your condo probably has a list of rules regarding renovations. If you have a building website it might be on there. In my condo building there are quite a few rules:
Renovation that makes noise can be done *only* between 9am and 5pm Monday to Friday.
Anything that affects the common elements of the building requires prior approval. This includes outside walls, but also any changes related to the windows, ventilation, electrical, or plumbing. So if you want to put a heat/ac duct into your new bedroom you will need building approval, as you may interfere with the air flow through the ducts of the building in general.
Hard flooring must also meet very specific requirements. Floating laminate or hardwood floors can be extremely noisy and echoey for residents below the unit, leading to many complaints. So our building requires an extremely thick underpadding to be installed beneath all these types of floors. We had to give the building management samples of both the floor and underpadding before installation. If you don't do this and you get complaints, they say they will force you to rip it out (don't know if that ever really happens, though).
The rules also state that plumbing and electrical work must be done by certified tradesmen. So if you do your own electrical and the place catches fire, you're up the creek, I guess.
Finally, we're not allowed to throw any construction related debris into the garbage bins. This includes drywall, old carpet and underpadding, 2x4s, ceramic tiles, etc. So you need to pay someone to take that stuff away too.
So pretty much the only reno you can do without permissions is painting.
All in all, these rules make renos a real pain, especially if you're a do-it-yourselfer, but I think from a communal perspective they make a lot of sense. Nothing like having your neighbour decide to jackhammer ceramic tiles off his floor at 5am on a Sunday, or do his own plumbing and cause all his neighbours toilets to back up, etc.
