can i use thompson water seal as a vapor barrier on the inside of exterior walls

I am converting a wood framed storage building into a rental cottage. The only problem the city inspector is concerned with is that there is no vapor barrier on the exterior walls. He said that he would do a little reserch to see what i can do without removing all of the exterior walls. He mentioned to me that I may can use Thompsons water sealer and spray it on the inside of the walls. Has anyone heard of this passing ICC code requirements?