I too have heard of some bamboo flooring problems. Definitely do your research h before you make your final decision. However, they are extremely great looking!

Can I get the company to put this layer of patina on the floors or is it naturally occurring? And does it happen on engineered timber floors?

We have seen a similar issue in the past. The problem occurred when the porcelain tile on the floor did not have 100% contact with the tile adhesive, this caused water to seep down though the grout join and hold in pockets under the tile in the areas where there was no direct contact. The water being trapped in the pockets under the tile does not evaporate and can leave the tiles looking stained. If this is the case with your floor tiles the bottom row of carrara marble tiles are simply acting like a sponge drawing water up. To fix the problem we would suggest that the bottom row of carrara marble and the porcelain tiles on the shower floor need to be removed and relayed ensuring full adhesive coverage. Unfortunately this may compromise your under tile heating and waterproof membrane. Proceed with caution.

Hi Nick The vinyl is a no go unfortunately as it needs a nice flat surface. Otherwise you will soon see the underlying pattern through. You have a couple of options though with the slate as others have suggested. Firstly I would check out the adhesion of the slate to the floor ie check if there are any loose pieces. Tap on the floor lightly with your knuckles over the whole floor or VERY lightly with a hammer or other metal object. You will soon hear hollow areas. If there is a lot hollow, I would break out the jack hammer and pop it all off. It's a bit of a job, but you can strip a large area in a day easily then grab a floor grinder to remove the adhesive. Again another day and messy but then you have a fresh start, or you can get a floor stripping company in to do it with little fuss. Options then become standard ie vinyl, other tiles or epoxy coatings. If you want to go over the existing floor, you can have a flooring specialist out that does self leveling epoxys or flowcrete to either create a marble style or polished concrete finish, a clear mirror level finish in which the slate looks like a pattern within the mirror floor or create a level surface from which you can then add your vinyl etc. Cathy are thinking of Laminam? It comes in a 3m x 1m sheet which I have seen used on floors but you can also get the 1m x 1m for floors and it is 3mm thick plus the backing. Cheers