I was at home depot, and I saw something they have called allure. It's a 12by 36 inch piece. When pieces are put in place, they bond to each other, but do NOT bond to the floor. Once down they can be moved within a couple minutes, but after that..... forget it. To secrue it around the perimeter you just use some sort of trim, and let it float as it expands/contracts.
My problem - I put it in my bathroom, and it has contracted a little (or maybe things weren't quite square enough for it) and it now has some gaps where it has come apart. When I say a gap - I mean not more than 1/16 inch. My big concern is that water will get into those areas, and lead to some sort of problem. Taking them apart is not an option, the floor wasn't perfect (this is a remodel) so i'm not sure if installing new ones would help. The biggest gap is right in front of the shower door. I was wondering if I would put the smallest amount of clear silicone in there if that would do the trick?