https://imgur.com/a/JZo9obQ

I’m insulating and finishing a 12x24 wooden shed in North Florida, and I want to do the roof the best possible way to fight the brutal Florida heat and humidity. I’m very new to all of this, so I’d really appreciate any advice before I start closing everything up with drywall.

Shed Details

12x24 wooden shed

LP SmartSide siding

Metal sheet roof

Ridge vent running the full length of the roof

No soffits/intake vents currently

My Plan So Far

I plan to fully insulate the shed and control the climate inside with:

Portable/window AC

Large dehumidifier

Before insulating, I plan to:

Caulk/seal all cracks and gaps

Seal where framing meets wall panels

Seal around windows, doors, etc.

For the walls:

Rockwool insulation

Kraft/paper facing toward the interior

Then drywall, finish, and paint

For the roof/ceiling:

R-19 Rockwool between rafters

Possibly add foam board insulation before drywalling

Then drywall the ceiling and walls

From what I understand, the ceiling drywall should go up first so the wall sheets help support it.

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My Main Questions

1. Moisture / Condensation

Will this setup be sufficient to prevent moisture buildup inside the wall and roof cavities once everything is drywalled in?

I’ve read that LP SmartSide walls are somewhat vapor permeable and can still allow moisture to escape outward. Is that enough if the interior is climate controlled and dehumidified?

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2. Roof Insulation / Heat Reflection

Would adding foam board between the Rockwool and drywall actually help reduce heat transfer from the Florida sun?

If so:

What thickness/type would you recommend?

Would foil-faced foam board help enough to be worth it?

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3. Ridge Vent Without Soffits

This is the part I’m most confused about.

Since the shed has a ridge vent but no soffit intake vents, what happens to the airflow?

I included pictures with colored lines:

Red triangle area = small attic peak area above the ceiling

Would that upper triangle area vent passively on its own through the ridge vent?

Or do I need to add:

Gable vents?

Soffit vents?

Some other intake vent system?

I’m mainly trying to avoid trapping hot, humid air or creating condensation/mold problems later.

Sorry if these are beginner questions — I’m trying to do this correctly the first time. Thanks for any help/advice!

Slowly figuring this out. Please help me understand airflow and moisture prevention.