The building code in this area says I should put vapor barrier on the
external walls between the drywall and the insulation. This is to
prevent in-house moisture from penetrating through the drwall and
insulation and condensing against the cold external walls. It's the
same building code across Canada.

Vapour barrier should be placed on the warm side of the wall. Anyplace in
Canada that would be the side towards the living space. It's to prevent the
humid air in the living space from getting through the wall and condensing
in your insulation and framing.

If you want to put any kind of barrier on the cold side of the wall, use
something like Tyvec... It allows air movement through it but is designed to
reduce moisture movement through it.