System 1 - Batten Strapping
This is the most complicated of the three systems, requires battens also called strapping, usually wood 2x2's. It is so solid is can be installed over open raters. With counter strapping this system combines lightweight strength and incredible ventilation. It is also an wasy and effective solution to straighten out existing roofs that have waved decks. System 1 should be installed by an experienced metal roofer.