Using galvanized tin for a small bathroom ceiling

A. Semantics, but you can not galvanize tin as it melts at a higher temp than tin. "tin cans" used to be steel with a thin tin coating and are not tin. That coating has virtually been replaced by organic coatings.

With the amount of moisture from baths or showers, that area is guaranteed to rust-someday- if you put up galvanized steel. This could be days, weeks or years, depending on the quality and the environment.

A. Yes, it is semantics. People use the slang word "tin" to refer to steel sheet metal, and it can be a bit confusing. Galvanized roofing will last many years or several decades outdoors, however:

1). It is not considered failure or rusting if the coating turns brown, due to its zinc-iron nature, whereas you might consider it unacceptable.

2.) Plenty of air (carbon dioxide) is required for galvanizing to work well. Voluminous white rust (wet storage stain) results if it can't breathe and I'm not sure if the ceiling will breathe well enough. But I have read stories in handyman magazines of it being used successfully.

Regards,