New Ceiling and Insulation Vapor Barrier

[Paul]

I'm building a new lower ceiling in a room with an existing vaulted ceiling. The existing ceiling has R19 insulation with a vapor barrier and vent baffles. This is covered by drywall. The existing ceiling doesn't provide enough insulation for the winter or summer.

The new flat ceiling at 9 feet high will have R38 insulation covered by drywall. Should the new insulation have a vapor barrier? If yes, which way does the vapor barrier face? I'm thinking that if a vapor barrier is used it could trap moisture between the old and new ceilings. If I don't use a vapor barrier how do I secure the insulation to the studs?

I live in Northern Ohio where winter temps drop to 0 degrees. Thanks for your suggestions.

[Gunner]

You're in my neck of the woods. What you're proposing to do will give you an unventilated _room_ above your living area. Not advisable. Your intake/exhaust for air movement will not be directed towards the area you're enclosing. You will be creating more problems than the existing one.

You need to create an unfinished _attic_ and proper air flow with intake/exhaust. Bigger mess yes, but do not try to short cut this project on the labor end.

You do not want a double vapor barrier, in our climate the vapor barrier is towards the thermal envelope.

[Joseph Meehan]

I agree with gunner. You could remove the existing drywall, and insulation. Build your new ceiling as planned and you could even recycle that insulation (without the vapor barrier) by laying it on top lf the new insulation. Assuming you have low vents that will be near the level of the new ceiling you should do fine.

[Paul]

Joseph, Gunner,

Thanks for your advice. I never thought that the dead air space could create a problem. After thinking about what you said, it makes sense. The enclosed area would heat up but there would be little way for the heat to escape. I suspect the problem would be more of an issue in the summer rather than the winter.

It seems like my only choice for this new ceiling is to do just what you said, and that is to remove all the existing ceiling drywall and insulation, and maybe the baffles too. This simple project is getting more expensive (I'm not doing the work).

Thanks again for pointing this out to me.