Re: Cork Flooring questions
As Houston said, the manufacturer's recommendations are what you need to follow, up to and including using their proprietary vapor barrier, even though it will be the same 6 mill plastic sheathing you can buy for much less at any hardware store.
Having said that, I would leave the vinyl in place, as long as it's not going to cause any transitional issues, meaning if vinyl only exists in one area where the cork will be laid and not all areas, there will be a noticeable difference in the finished floor at those transition areas. You have two options here, either remove all the vinyl, or fill in the bare areas with new vinyl before laying the floor. Even though the vinyl will act as a VB, still follow the manufacturer's recommendations and install an additional VB over the top of the vinyl.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!