How to fill the joint between tiles and cabinets in a kitchen backsplash

If your tile is not secure, then the backer is not secure either. You will need to gut it to the studs and install water proof membrane, concrete board or heavy hardy-backer to tile over. The window frame must also be carefully water-proofed as well and trimmed out with a moisture resistant material. Get some professional advise on this one, a new tile job is not cheap or easy and be a shame to have a leaky, grout dropping job when you're done.

As far as the type of tile, ceramic or porcelain are similar products, difference being the hardness grade and the type of glazing. Porcelain is always a better choice in my view as the surface glaze is smoother, easier to keep clean and usually a harder grade.(3 to 7) prices can vary wildly, usually again because of the glazing and hardness factors. Designer patterns also effect the cost as well.

I spend a lot of time in France and in the midwest US.

Customary in France if you put up a backsplash is to extend it before putting up cabinets. There is no caulking usually between the backsplash and the cabinets.

Also the cabinets would be floating on the bottom most of the time. And the bottom cabinets are on legs - where in America they are almost always enclosed. Maybe this allows any leakage from backsplash to hit the floor easy.

It is just a different way of doing things because people are accustomed to taking their cabinets and everything with them when they move. I have seen this trend slowly change over the past 10-15 years though in that you will walk into some apartments or houses now with the kitchens already done but this is not the norm.

And obviously you do the backsplash last in the US because we like everything permanent looking. You use less tile and it is just easier to do that. Also - and just my opinion - but homes in the US are built... lets say faster. So you don't always have right angles, your floors are slanted a little, the walls wave a little... Meaning that it looks better to have shimmed cabinets. I have installed IKEA cabinets in kitchens in the US and people look at me like I need to fix their walls when the cabinets don't sit flush.

Personally I think it would be good to do a little of both. First it is kind of dumb to take your kitchen with you - which may not work in your next space and then you sell off pieces for a fraction of what you paid. But I am also a huge huge fan of keeping lowers on legs and having more mobility in your cabinets.