I'm building a heated timber frame workshop as an addition to my free-standing garage. Am using Timberpeg's "wrap and strap" wall system. This calls for (going from inside to outside wall):
* EWP frame
* 7/8" pine t&g
* 6 mil poly vapor barrier
* 3" polyiso foam wall insulation, reflective facing on 2 sides(inside perimeter blocking)
* 1x4 strapping to create air space & nailers
* house wrap (Tyvec)
* CVG WRC horizontal siding (which I will back-prime)

Question:
Does it make sense for the Tyvec to go between the strapping and the siding? With rain drainage wall systems, I thought the usual practice was to but it BEHIND the strapping and leave an air space between it and the Tyvec.

It seems to me, this plan might increase the R-value a little (because the faced polyiso performs better with an air space) but
decrease the moisture-management.Having Tyvec directly behind the cedar siding would seem to defeat the purpose of the air space, from a moisture-management point-of-view.

Thoughts?