Condensation on tenant walls. What to do?

[Isaak Brown]

Hi all, Thanks as always for any help and advice. Tenants are experiencing heavy condensation. Walls or damp to touch, and some clothes are now moldy. We've brought in two dehumidifiers which are helping, but I'm not sure what the root problem is or even who to ask for help. One contractor said moisture is coming through a hole in the exterior stucco, but another said no way because the vapor barrier would block it. 1st one recommended installing insulation, but I've also read this can increase condensation problems. Any experience with these issues? We're not even sure who to call to solve this problem! Isaak