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https://imgur.com/a/JZo9obQ I’m insulating and finishing a 12x24 wooden shed in North Florida, and I’m trying to figure out the best way to handle the roof/ceiling before I close everything up with drywall. I’m very new to this stuff, so I’d really appreciate advice from people who’ve done similar builds in hot/humid climates.

Shed Details

• 12x24 wooden shed
• LP SmartSide siding
• Metal sheet roof
• Full-length ridge vent
• No soffit/intake vents currently

My Current Plan

I want the shed to be fully insulated and climate controlled using:

• Portable/window AC
• Large dehumidifier

Before insulating, I plan to:

• Caulk/seal all cracks and gaps
• Seal framing joints
• Seal around windows and doors
• Basically make it as bug-proof and weather-tight as possible

For the walls:

• Rockwool insulation
• Kraft/paper facing toward the interior
• Drywall + paint

For the ceiling/roof:

• R-19 Rockwool between rafters
• Possibly foam board before drywall
• Then drywall everything

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

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Main Questions

1. Moisture / Condensation

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

I’ve read that LP SmartSide is somewhat vapor permeable and can still let moisture escape outward. If the interior is air conditioned and dehumidified, is that generally enough?

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2. Roof Insulation / Heat Reflection

Would adding foam board between the Rockwool and drywall noticeably help with Florida heat coming through the roof?

If so:

• What thickness/type would you recommend?
• Is foil-faced foam board worth doing?

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3. Ridge Vent Without Soffits

This is the part I’m most confused about.

The shed has a ridge vent, but no soffit intake vents. So where is the airflow actually supposed to come from?

I included pictures with colored lines:

• Red triangle area = small attic peak area above the ceiling

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

Or do I need to add:

• Soffit vents?
• Gable vents?
• Some other intake system?

Mainly trying to avoid trapping hot humid air or creating mold/condensation problems later.

Sorry if these are beginner questions — I’m trying to do this correctly the first time instead of regretting it later. Thanks for any advice!

So when drywalling these walls in. Do I just culk all contact points between the 2x4s and the siding to completely seal it and then Use faced rockwool and the drywall? Or do I need to drill vent holes in each topplate of each studbay? To allow air to flow up and out the roof vents?? I don't want to trap air if that'll be an issue. Someone told me the walls will allow moisture to escape. But seems sketchy.

I’m turning my 12x24 wooden shed into a fully insulated/drywalled space and I’m trying to do it correctly from the start. The shed has a metal roof with a ridge vent already installed.

Location: North Florida

Climate: Hot, humid, lots of moisture

Goal: Make it sealed, bug-proof, moisture controlled, and comfortable year-round.

What I already have:

- Large standalone dehumidifier

- Rockwool insulation

- Foam board

- Drywall

- A ton of DAP caulk

Current plan:

1. Caulk every crack, seam, window edge, etc. to seal it up and help waterproof/bug-proof it

2. Insulate walls with Rockwool

3. Insulate ceiling/roof area with R19 Rockwool

4. Add foam board

5. Drywall everything

Where I’m confused is the ventilation/moisture side of things.

If the room itself is fully sealed and I run a dehumidifier constantly:

- Is that enough to control moisture?

- Or do the wall/roof cavities themselves still need airflow?

In the pictures:

- The BLUE lines represent the airflow path I’m talking about (air traveling upward through the cavities and out the ridge vent)

- The RED lines represent possible vent holes/openings between cavities that I may need to add

The shed already has a ridge vent, so I’m trying to understand if I ALSO need soffit/intake vents so air can travel upward and out of the ridge vent.

Basically:

- Do I need to add the red-line vent holes/openings between cavities?

- Do I need vent baffles under the roof insulation to keep airflow moving along the blue-line path?

- Or can I fully seal each cavity, insulate, drywall, and rely on the dehumidifier?

I’ve also been recommended radiant barrier, but I’m confused on the proper way to install it.

Questions about radiant barrier:

- Does it go directly under the metal roofing?

- Does it need an air gap to work correctly?

- Would the correct order be:

metal roof → air gap/radiant barrier → insulation → drywall?

Or should the radiant barrier be between the rafters and drywall instead?

Trying to avoid:

- Condensation

- Mold

- Trapped moisture

- Hot attic effect

- Bugs getting in

Anyone who has insulated a shed in a hot/humid climate, especially Florida, I’d really appreciate advice or pictures of your setup.