I'd start w/the Instructions. For a kitchen, are you SURE you want a sub-floor of particle board??? If that's what you have, you better be SURE that a drop of water doesn't get to it. It will swell like a balloon and you won't get it to 'go back to its original shape'.
Beings it's a floating floor, even the addition of tar paper may not help. My best to ya and hope this helps.
Jay J -Moderator
PS: Perhaps you can contact the Mfgr for suggestions on a Kitchen Installation (vs. a bedroom installation ...) The LAST thing you don't want to do is VOID a Warranty. (A particle board sub-floor MAY just do that ...)