Water stains on ceilings are a giant red flag to potential home buyers. Thankfully, they are a relatively easy fix.
Find the source. Damage shouldn’t be repaired until identifying the source of the problem. Call a qualified plumber to identify and fix suspected leaks. If plumbing isn’t the issue, have a certified roofing expert perform an inspection.
Drying out. Check to see if the drywall is wet. If so, wait for it to completely dry before starting repairs. Try using a dehumidifier to get rid of excess moisture. Is mold present? Wash small areas with a bleach solution. However, large mold areas, which pose a health risk, should be dealt with by a remediation specialist.
Inspect the ceiling. If the ceiling is sagging, a structural problem is likely. Have a professional contractor assess the damage. A stain alone is a relatively easy DIY project. Apply a stain-blocking primer. Two coats are likely needed. When dry, paint the entire ceiling.