Vapor escape and vapor barrier:
Insure tight joints where the finish material connects to the finish groove and to the ceil- ing - detail 1.
Install vapor barrier to the finish groove - details 2.
Install underlayment up against the frame on all four sides and establish over-flashing drainage at the top - details 2.
Consider use of VELUX underlayment (type ZOZ 121 in US and ZOZ 211 in Canada) in areas with severe weather conditions and on roofs with low roof pitch.
Insulate carefully around skylight always maintaining min 1/2" (15 mm) distance to flashing - detail 3.
In cold areas a combination of flared and 4" (100 mm) perpendicular lining at top and bottom allows for better insulation - detail 4.
The Following User Says Thank You to djlandkpl For This Useful Post: