I live in Miami and have a metal roof which needs new screws. A roofer took up one of the panels and told me that there is no plywood under the roof. The metal roof is screwed into the main roof beams. Does there have to be a plywood roof under a metal roof?
Thank you

No. Not unless you feel like lining that guy's pockets that is.

Being in hurricane country, your house would stand a better chance of surviving with sheathing. However, if you aren't replacing the metal I would side with twinkiedooter from a cost standpoint.

Thank you very much for you input... it is welcome

The roof is a cathedral ceiling with solid boards on top. The metal roof is on top of this roof.
There is no plywood.
The roof was put on around 1991 and just screwed into wood placed on top of the roof. I have attached a photo.

The roofer is suggesting replacing all the screws since many of the water seals on the top of the screws have broken or split. We have some leaks.
What do you think?
-Do I need a plywood layer placed on top?
-Should there be insulation or a water barrier between the metal roof and the wood roof. If there is not one is it a big issue?
-There are some rust spots on the roof and under some of the screw holes but not extensive. Is this a problem?

Thanks so very much.

PS. You signed your name Howe.. My wife was Margaret Howe from Franklin, Mass.

No, your T&G roof deck acts as the decking. However, from the picture and your description, you have no insulation. Correct? Doesn't that give you a good heatload in the summer? Or is their solid sheet insulation and a second wood decking?

By present & active building code all residential roofing permits in Miami-Dade County only allows metal roof panel clipped over plywood deck. By missing the plywood deck you might have an issue with overworking your A/C system to cool down the inside of your house. Depending on the gauge of your metal roof panel and the amount of clips tying down them to the deck, you might have a safe envelope during high hurricane winds. Would require an inspection from a metal roof contractor to really ascertain it.
Please browse www.imetal.us for more info.

Metal roof panels have to attached to 1/2" min plywood deck or another solid substrate that has equal holding power of fasteners. Your purlins are probably 24"o.c. and for Florida roof panel attachments have to be 20" o.c.max, better 16". You can try to make general contractor or roofer who installed the roof originally responsible for this and you can make them pay your re-roofing bill.

I work for metal roof panels manufacturing company and you absolutely need to have solid decking and ice & watershield underlayment (possibly 2 layers of felt underlayment) under metal panels.You can have rigid insulation on top of plywood decking or if you have attic space you can have standard attic insulation above the ceiling.