Section 9.25 of the code deals with Heat Transfer, Air Leakage and Condensation Control
9.25.1.1.
2) All walls, ceilings and floors separating conditional space from unconditioned space, the exterior air or the ground shall be
a) provided with
i)Thermal insulation
ii) An Air Barrier System
iii) A Vapour Barrier
b) constructed in such a way that the properties and relative position of all materials conform to Subsection 9.25.5.
3) Insulation and sealing of heating and ventilation ducts shall conform to Sections 9.32, 9.33.