Atlas´ polyiso sheathings are not designed or intended to provide a long term exterior weathering surface for the structure. Stucco Shield must be covered quickly after installation ( within 2 weeks ), in order to prevent job site contamination of the working surface. Energy Shield, Energy Shield Plus and Rboard may be left exposed as long as 60 days prior to installation of the wall claddings, however, all exterior sheathings should be covered as soon as is practical.