The floor in the kitchen is finished! I still have to fix it to the floor of the house, but I don´t know how I am going to do that.
It is made of a sort of roofing material (for a 1:1 house) I think. It was a big sheet with tiles cut into the material. I had to do the grouting myself, which I did à la Josje (http://josje.bouwt.com/homepage/show/pagina.php?paginaid=275637&c=0d6c46bc).
I think it has become a nice floor.