How do you best use polyiso insulation in a basement?

Iain Matheson
Updated: Sept. 9, 2020

Polyiso foam board :  fiber faced (white) (IKO Therm 3) or the older product,  Organic faced (gray) polyiso. Both products have visible 2mm (+/-) holes in both sides of the facing material;

My Question regarding Polyiso (moisture and thermo) performance:  

Central, Vancouver island, Canada.  

Below grade 8’ total height, (2’ above grade, 6’below).  Polyiso tightly butted together but not taped & in direct contact with/held against,  inside of 8” thick concrete foundation wall by 2x4 stud framing,  (bottom plate N0T in direct contact with concrete floor but iso is) Stud bays properly filled with Roxul/rockwool insulation, NO poly vapor barrier & ½” gypsum drywall, sealed with drywall sealer and painted with vapor barrier paint. 

What problems do you see with this detail?  Thank you

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