Where does a vapour barrier go when building a shed in southern Ontario?

Charley Nelson
Updated: Nov. 12, 2020

I have worked my way through 75% of building a shop in my yard. Having obtained a permit I have been subjected to the archaic expectations of the local building department who insist on insulating to a certain level as the shed is larger than 10 x 10. Since I found this web site, I have put a rapid halt on the building. I have always suspected vapour barriers as being fundementally awkward, depending on which way heat was infiltrating. Talking to inspectors, I get the same cookie cutter response..."you're the builder, you should know the code." They get upset when I point out that building code is minimal, at best, and I dislike "minimal at best".

So, having read all about vapour barriers, air barriers, etc, how they work, how they differ... I wonder what my next best move would be.  Currently I have 2x4 16"oc walls with 1/2 plywood exterior sheathing, R14 roxul batts and the infamous 6 mil poly. The ceiling is R40 pink as I got a good deal, and figure if it cost the same as R24, may as well enjoy the ROI. I was going to clad the interior with 1/2 ply, primed and painted, but then material in this area tripled in price, and made me rethink the whole interior finish. I was trying to stay away from drywall because of it's rotting capabilities, and is quite prone to damage in this type of environment. I have chosen a combination of 4 ft of drywall above a wainscotting made from skid wood.

Back to my quierie, I am in section 6 of the  temperature region, southern ontario, and enjoy anything from 32 below to 42 above zero. Saw dust, a highly combustable substance, has forced an electric heating system, so insulation and air exchange is the primary concern in this project. 

Keeping in mind that the vapour barrier is best served inside the wall as opposed to either side.... what woud be the best course of action going forward?

Responses (1)