I did have a mold issue in the bathroom shortly after buying my house (a few years before adding insulation). Had to redo the ceiling paint job, which was annoy

I did have a mold issue in the bathroom shortly after buying my house (a few years before adding insulation). Had to redo the ceiling paint job, which was annoying to be sure, but that was about the extent of the damage, and we never got a mold problem again afterwards. I also did have someone come over to quote me on insulation work when I was planning it (since the mold thing was a concern). They said my setup was fine as far as mold risk was concerned, and that it was clear that the two layers that were there were insufficient. If in doubt, you can always ask for a professional opinion before attempting any DYI.