1.1.3. Subject to section 1.1.4, this Chapter applies to the addition work of existing buildings where, after that work, the building including its addition(1) has a building area of more than 600 m2 within the meaning of the National Building Code as adopted by Chapter I of the Construction Code;
(2) has a building height of more than 3 storeys within the meaning of the National Building Code as adopted by Chapter I of the Construction Code; or
(3) does not house only dwelling units.