underlay and decking required?

I have to install a metal tile roof for a new construction in a tropical / coastal environment. Design calls for exposed rafters with sheet rock in between. Above the sheet rock the plan calls for solid insulation (Polystyrene) battens and then the metal roof. Is there a need for decking and/or underlay or is the design adequate? Thanks for your help		Edward Ake 8/12/2013	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/18667/find/
I would recommend decking and underlayment, to avoid condensation. I also would suggest you consider aluminum as an option over steel since you're in the islands. I know that the following MRA manufacturer members make aluminum tole facsimile products: ATAS International, Metal Sales, Classic Metal Roofing Systems.		Todd Miller Isaiah Industries, Inc. 8/12/2013	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/18668/find/
Do you mean battens or baffles? +1 on running aluminum. That is a must.		Eric Novotny An informed customer is the Best Customer! 8/13/2013	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/18669/find/

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