Correct Storage Procedure
The protective nature of both the zink and paint coatings of steel sheeting can be seriously impaired when exposed to wet conditions for extended periods of time in absence of air flow.
The zink surface becomes susceptible to corrosion during prolonged storage without the necessary precautions.
Safe Storage:
To prevent unnecessary damage to galvanized, zinkal and colour coated coil or profiled sheets, special precautions should be introduced to eliminate contamination by moisture.
If galvanized,zinkal and colour coated coil or profiled sheets are not required for immediate use, coils or packs of sheets must be stored off the ground on site under properly designed cover, protected from wind driven rain. Plastic tarpaulins that completely envelop packs of sheets or coils should not be used, because a sudden drop in temperature may result in the formation of condensation or water vapor which can easily be drawn in between nested sheeting by capillary action.
For more information, please see the below links from coil manufacturers:
http://www.chromadek.com/Web_datasheet_c1.10.pdf
http://safalsteel.co.za/wp-content/uploads/2013/05/Maintenance_Guidelines_p.pdf
