Charlie
Check your by-laws and see what it says about doing work in the building or changing the appearance of your ‘lot’.. Generally, if the deck is yours then the pergoal will be too. But anything you do that affects common property or the amenity (e.g. outlook) of other owners has to ne approved by the Owners Corp or Executive Committee. For instance, drilling a hole in the hall to support the roof affects common property so you have to get their OK. In any case, letting people know what you are doing is just being a good neighbour – there’s no need to get territorial about stuff. Just let people know and then you’ll find out if there’s likely to be a problem.