For Major work you require a special resolution by-law as outlined in Section 108. This will require you to convince a 75 percent majority of owners voting at an AGM or EGM that your plans are sound and safe and to give an undertaking to maintain and repair common property involved in the structural change. You will also have to pay for the by-law and the cost of the meeting if it is an Extraordinary General Meeting.
I would recommend discussing this with your strata committee and/or strata manager from the beginning so that they can endorse and support your application.