Queensland’s body corporate laws are so arcane and complex that I am reluctant to even offer a response. Fortunately I found this online which explains a lot.
It seems that changes to common property require a special resolution at a general meeting and that would seem to apply here. I don’t think that approval for something that changes the look of the building can be approved by the executive committee either.
Your committee really needs to get professional advice on this before anyone changes anything. But in most states, changes to common property and the look of the building require special resolutions at a general meeting.
And here are a couple of standard Queensland by-laws.
5 Damage to common property
(1) An occupier of a lot must not, without the body corporate’s written approval, mark, paint, drive nails, screws or other objects into, or otherwise damage or deface a structure that forms part of the common property.
8 Appearance of lot
(1) The occupier of a lot must not, without the body corporate’s written approval, make a change to the external appearance of the lot unless the change is minor and does not detract from the amenity of the lot and its surrounds.