Sweating insulation in ceiling

[wbh123]

I live in a 70 year old 1200 sf 1-1/2 story house. The roof system is 2x6 rafters. The upstairs ceiling is vaulted with a peak inside. The insulation lies directly against the tarpaper on the outside the kraft paper moisture barrier directly against the sheet rock inside ceiling. There is no dead air space between the shingles and sheet rock other than the R-19 insulation. Therefore there is no ridge vent on the roof-only ridge cap shingles. About 5 years ago I had the house reroofed. After that the sheet rock in the peak of the ceiling began seperating and caving in due to moisture in along the peak of the ceiling. I am removing all the sheet rock and replacing it with painted bead board nailed to 2x4's attached to the rafters. This will create an 1-3/4" dead air space between the ceiling and rafter/ insulation. At this point i do not beleive the ridge cap is leaking. To eliminate condensation on the insulation I am proposing instaliing some vented soffit and a ridge vent. It is not possible to install baffles between the insulation and roofing material without replacing the entire roof. I hope this arrangement will allow the ceiling just enough breathing room to prevent sweating on the vapor barrier of the insulation. I realize this situation is not optimum but its the best I can do. What does everyone think-will it work?

 

[Steve123]

You lost me with what you have and possibly what you are doing.

But you say "1-3/4 dead air space". No, I don't think a dead air space will accomplish anything. You should have air FLOW. But you also say vented soffit and ridge vent. So ???