Originally Posted by RonS
I also have the same gap problem. I do not have the reflectix in any of the upper cabinets that I can see only the liner (but I do have the insulation package). Do you think the liner itself is a sufficient vapor barrier? Can you detect any reflectix in your upper cabinets?
Ron the liner should be an excellent vapor barrier.
I just started working on the rear cabinet with the about 2" gap of uncovered fiberglass. I cut a piece of Reflectix and crammed in between the wood and the existing Reflectix, against the bare fiberglass. Then I covered the entire gap with aluminum foil tape to give it a decent vapor barrier. In the cabinets with small gaps I found some self adhesive weather stripping just the right size so that I can stick to the wood frame and have it push tight against the liner to bridge the gap.
(If Mary and I didn't love to travel in the cool and cold seasons, none of these gaps would be of any real importance and I could be having a homebrew instead of trying to work via a mirror inside those cabinets!)