corrugated metal roof?

my porch is an add on to an original cabin structure. the porch is typical stick and frame construction consisting of 2"x4" joists spaced at approximately 12". plywood was secured to the joists by nail, roofing felt, cold asphalt and asphalt roll. the porch is intended to have the same low pitch as the original structure it was added to.

the cabin is subjected to triple digit heat, high winds and annual rainfall of about four inches of the high desert. due to these conditions the plywood base (which is exposed on the underside of the porch) expands and contracts with heat and moisture creating gaps. the high winds blew through the underside gaps taking the asphalt roll off of the porch.

my intentions are to remove these materials from the porch replacing them with (gap less) corrugated metal. my concern/questions; is it possible to use corrugated metal in this specific porch application? what gauge/type would be appropriate(29,TR-36,AG,utility)? should i be concerned about thermal expansion and movement of the metal? painting of metal with ceramic coating for heat reflectivity? what type of flashing would i use to join the existing asphalt roll of the cabin with the new corrugated metal of the porch? pictures attached. thanks for your opinion

It won't work! If you want to use corrugated metal, do the whole thing with it. It is about impossible to tie the two together, especially going from the rooled roofing to the tin. If you want to use a "rolled" roofing, get some S. A. Modified cap sheet with a S. A. base sheet and to the whole thing. What is the pitch of the roof?

here are the pics: [img width=100 /]http://i1137.photobucket.com/albums/n517/jgrobert57/porch_cabinROOFS_small.jpg/img] [img width=100 /]http://i1137.photobucket.com/albums/n517/jgrobert57/cabin_porchROOF_close_small.jpg/img] [img width=100 /]http://i1137.photobucket.com/albums/n517/jgrobert57/underside_small.jpg/img] [img width=100 /]http://i1137.photobucket.com/albums/n517/jgrobert57/underside_2_small.jpg/img] [img width=100 /]http://i1137.photobucket.com/albums/n517/jgrobert57/windBLOWN_small.jpg/img] [img width=100 /]http://i1137.photobucket.com/albums/n517/jgrobert57/windBLOWN_2_small.jpg/img]

or

[IMG]http://i1137.photobucket.com/albums/n517/jgrobert57/porch_cabinROOFS_small.jpg[/IMG] [IMG]http://i1137.photobucket.com/albums/n517/jgrobert57/cabin_porchROOF_close_small.jpg[/IMG] [IMG]http://i1137.photobucket.com/albums/n517/jgrobert57/underside_small.jpg[/IMG] [IMG]http://i1137.photobucket.com/albums/n517/jgrobert57/underside_2_small.jpg[/IMG] [IMG]http://i1137.photobucket.com/albums/n517/jgrobert57/windBLOWN_small.jpg[/IMG] [IMG]http://i1137.photobucket.com/albums/n517/jgrobert57/windBLOWN_2_small.jpg[/IMG]