Vapor barrier for existing roof?

[Gillespie85]

My building was built without a vapor barrier between the roof metal and truss (see pic below). I plan to finish off the inside and am wondering what my options are for adding a vapor barrier. I plan to add a ceiling and blow-in insulation above it.

Thanks in advance for any suggestions on the vapor barrier issue.

 

[Gillespie85]

or should i be considering a vapor barrier on the walls too?

 

[Gillespie85]

I have done a little reading, and as I understand it... the vapor barrier should go on the inside of my insulation.

So for the ceiling, I should be installing the vapor barrier, then my ceiling... and after that is done, blow in the insulation above ceiling?

For walls, I should be installing my insulation, then a vapor barrier, then my 2x4 framing & walls?

Any vapor barrier product recommendations? I see people say not to use poly.

 

[bobbyjean]

do you have soffit or ridge vent? looks like large span on the trusses....
i see many people using reflective "bubble" wrap for that job....think you will find alot of info on this site about this......if you dont have soffit or ridge vents... i wonder if you could go with spray foam and have an open ceiling? garage looks great

 

[Gillespie85]

yes, i have soffit and a ridge vent. trusses are 40' and spaced every 8ft.