VAPOR BARRIER LOCATION ON A METAL BUILDING

QUESTION  FROM C. J.  FROM ARCHITECTS DESIGN STUDIO:

Regarding a vapor barrier location on a metal building, can i install a 3" vinyl faced insulation on exterior side of metal building with the vinyl face on the interior side then add a 6" unfaced insulation on the interior side to fill the girt/wall cavity on the interior side? or should the exterior 3" be unfaced and interior 6" have the vinyl face since a moisture barrier would be located in the middle with the first method? please advise.
 


 ANSWER FROM THE INSULATION DOCTOR:
 Thank you for your question.  

Your second method is correct.  The exterior 3" unfaced and the interior 6" vinyl face.

Sincerely,
Bruce Jones
The Insulation Doctor