How to clean metal roof oxidisation?

AGM

Hello Hello!

Thank you for reading this and in advance thank you for your valuable guidance.

The pic attached is from garage. The roof inside is getting oxidized (from my understanding) and you can see white color patches in a few areas.

Tried out by cleaning with Selleys Sugar Soap Wall Cleaning Wipes and also used Selleys mold cleaner thinking it may work! But both didn’t work.

Any ideas to get rid of this? Options thinking is to paint the inner roof with Dulux Metal shield Epoxy Enamel.

Appreciate any guidance and suggestions.Pic 01Pic 02Pic 03

EricL

Hello @AGM 

The white powder that often forms on galvanized steel is usually zinc oxide. Galvanized steel has a protective zinc coating that shields the underlying steel from corrosion. Over time, this zinc layer can react with oxygen in the air, producing zinc oxide, which appears as a white powder. This process is a natural and anticipated aspect of galvanization, contributing to the steel’s corrosion resistance. As long as the zinc coating remains undamaged, the steel beneath stays protected from rust and deterioration.

The zinc oxide corrosion will dissolve readily in weak acidic solutions. Ordinary cleaning vinegar has been found very effective and environmentally benign. Commercial products like CLR, for scale and stain removal, can also be effective. Please note that it might be necessary to use a stiff scrubber for the hard to remove build up.

If you need further assistance, please let us know.

Eric