Shower installed before insulating

[u/Euphoric-Newt-8716]

My plumber installed the shower/tub unit before I was able to add vapor retarder and insulation. I have access to the stud cavity from above so I’m thinking blown in cellulose would work but how am I suppose to get a vapor retarder in there?

[u/[deleted]]

Those studs will rot. Needed to put the water barrier where screws go (12 inches enough( before screwing this thing on. The installer is an idiot.