If the mold is only on the surface, cleaning with a vinegar solution (not bleach, as it doesn’t kill the roots) can be effective. However, its recurrence and spread suggest a persistent moisture issue. In villas, this often stems from a leak in the plumbing chase, poor ceiling insulation causing condensation, or inadequate bathroom ventilation.

Given the location along the ceiling and the allergy symptoms, the mold may have penetrated the porous gypsum board or be growing behind tiles. Disturbing it yourself could aerosolize a significant number of spores, worsening the indoor air quality and your wife’s allergies. A professional inspection is warranted to identify the hidden moisture source. They use moisture meters and borescopes to see inside walls without unnecessary demolition.

The cost for professional remediation varies significantly. It is primarily driven by the extent of the infestation and the required repairs, such as replacing water-damaged drywall. For a precise assessment and to avoid unnecessary costs, request an onsite evaluation from a company that provides detailed scopes of work and, crucially, post-remediation verification to confirm the mold and moisture problem is resolved.