[welch-time]

I've looked at the solid vinyl flooring planks for our cottage too. Costco has some really nice stuff. Never noticed anything about a wood core but I suspect there are different variations and manufacturers. The stuff I'm looking at is really thin so it can't have a wood core. I'd stick with the "Waterproof / Solid Vinyl" variety. The really nice ones have a pre-installed foam backer layer. The flooring floats on the subfloor (or old flooring) so as long as you don't glue it down and allow some room for expansion around the perimeter it should be fine.