Turbine, gable vent, or nothing?

[tsmart]

I have a 30x80x10 steel building, typical roll insulation.Has ridge vent. Florida. 3/12 pitch. I built a nice apartment inside with a suspended ceiling. Above my suspended ceiling, air doesn't move, it's very hot up there. SO: turbine, gable vent or exhaust fan? Or nothing? Thanks.

 

[niget2002]

You have a ridge vent but no air movement?

Ridge vents require an air inlet. Usually there's vents along the underside of the eaves for air to come in that then gets pulled out through the ridge vent. When you built your walls for your apartment, did you leave air gaps for air to get up into that area?

 

[ybnormal]

also, what kind of roof? hip, A-frame, gable, etc?

 

[tsmart]

As I understand it, the ribs in the steel roof carries the hot air from eaves to ridge. Insulation is in contact with the roof. The space under the roof insulation but above the suspended ceiling is really hot, my idea is to get rid of that hot air hopefully lowering power costs.

 

[tsmart]

Gable ends. 3/12 pitch. Before apartment.

 

[The Tool Tyrant]

Being as your building is so long and narrow, personally I would go with four evenly spaced turbine vents.

 

[tsmart]

Gable ends. 3/12 pitch.

 

[My Old Tools]

My building has the typical roll insulation over the frame, but on the roof I added another 8 inches with strapping. Makes a huge difference in heat gain up there.

 

[tsmart]

Interesting. Strap "frame" first then roll out insulation? What did you use for strapping?

 

[rayra]

How is the ridge vent doing anything at all with that fiberglass sheet insulation lining the entire roof deck?
The standing ribs don't allow enough air movement to matter.

Gable vents as high to the roof girders as you can get. Preferably powered. Pulling outside air in at one end and venting out at the other.

 

[racecougar]

Agreed that the ridge vent doesn't make sense here, as there is no appreciable air inlet, nor any appreciable space above the insulation (from what I understand, the roof is directly on top of the insulation). Additionally, the ribs of the R-panel roof should have been sealed with closure strips at the eaves to keep bugs/wasps from building their homes in there.

The space above your drop ceiling is technically conditioned space, as it's below the insulation. I would advise increasing the roof insulation rather than venting that space to the external environment.

 

[My Old Tools]

Interesting. Strap "frame" first then roll out insulation? What did you use for strapping?

Steel strapping. Extra insulation added after close in I'm pretty sure. I didn't get to watch that part.

 

[tsmart]

Agreed that the ridge vent doesn't make sense here, as there is no appreciable air inlet, nor any appreciable space above the insulation (from what I understand, the roof is directly on top of the insulation). Additionally, the ribs of the R-panel roof should have been sealed with closure strips at the eaves to keep bugs/wasps from building their homes in there.

The space above your drop ceiling is technically conditioned space, as it's below the insulation. I would advise increasing the roof insulation rather than venting that space to the external environment.

Makes sense. Thank you.