We did an addition to my home in 2008. The ceiling in the bedroom has an apex. The paint is peeling at the apex where it was taped and painted.  The nails are corroding and paint is bubbling and falling down at the nails.  This is only happening at the apex on each nail. The tape used to smooth the seam at the apex is peeling away too.  On the paint that chips away, there are rust stains from the nails.  We have had this repaired before about two years ago, and now it’s happening again.  Do you think its the type paint or type of nails used and what can be done to stop this from happening again?