Countinous insulation and mounting blocks – GreenBuildingAdvisor

What is the best way to install mounting blocks in this scenario?

I have 1.5″ polyiso board then 3/4 furring supporting 7/8 corrugated metal.    I am starting rough in and haven’t installed the polysio board yet.    Intuition is telling me to put the block directly on the polyiso and fasten it through instead of mounting to the sheathing.   The blocks are for lighting, dryer vent, electrical outlets, and hose bibs.   I think I am going to have to make my own blocks as I haven’t found any that will cover my siding thickness.

Didn’t see anything in the details library on this and why the question.

Thanks

Ron