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.

Bruce Jones
The Insulation Doctor