Hardie Board Prevail panels over exterior EPS board
I Live in dry and cold Alberta, Canada. I am planning to install Hardie Board Prevail boards attached to 1×4 strapping over 4″ of EPS insulation . I will be using a Tyvec barrier on the sheathing below the EPS. The Hardie installation guide calls for a water-resist barrier on top of (on the outside of) the foam as well. Why? Is this necessary? Surely it will serve to trap water vapour within the foam rather than release it? I would like to hear your thoughts on this. Thank You.
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