Re Roofing
In a new construction, is sheathing required on a roof if the the roofing material will be metal.
No. If the trusses are adequately cross braced, the sheet metal roofing can be affixed to 2"x4" purlins installed perpendicular to the top truss chords.
Just as I thought, thanx!
Here are a few installation examples from a radient barrier ste
http://www.btubusters.com/rafters.gif
Over open trust / rafters
http://www.btubusters.com/new_wood.gif
**Over new roof decking **
http://www.btubusters.com/old_wood.gif
Over existing shingles
There are 3 types of metal roofing systems. Architectural, Structural and metal shingles.
Architectural panels like standing seam need decking as does metal shingles. They also need underlayment.
Structural metal panels like you see on pole barns span over purlins and do not require decking.