Haw to inulate and vapour barrier a cathedral ceiling

What is the roof framing look like? If it is wood joists which is most likely, stuff the insulation between them, staple the vapor barrier on and apply your drywall.

I started using a semi-permeable vapor membrane recently due to mold and moisture issues. It allows the wall to breath. Check it out:

MemBrain Smart Vapor Retarder (http://www.certainteed.com/CertainTeed/Homeowner/Homeowner/Insulation/Prodindex/Residential/MemBrainProdIndex.htm)

However you decide to do this, it is important to provide ventilation space above the insulation for air to enter at the bottom of each rafter space and exit at the top through a ridge vent. Thus, if the rafter measures 10 inches deep, put 9 inches of insulation in the space, leaving the top one inch for air to flow. The air flow is necessary to keep any moisture from building up in the ceiling. Then staple a plastic vapor barrier to the bottom of the rafters.

If you wish to add more insulation value, you could attach rigid foam board below the rafters and apply 5/8 inch fire-rated sheetrock over the foam.

It all boils down to how much space you have between your ceiling surface and the underside of the roof. Tell us a bit more about this space and the type of construction. Is this a log cabin?

How would you charge and give estimate to do a job like insulate and vapour barrier the cottage. By the hr or sq ft and what is a good number to use. Thanks
Darren