Thank you so much for the tips, and thanks Jstrats for starting the thread.
To fill in the information the floor tile is the 25mm white ceramic mosaics.
The L-shaped kitchen counter unit needs to be self-supporting, although it is not so high (425mm), it is required to span over a horizontal distance of approximately 3000 mm. It'll be supported vertically by unit dividers at 400mm intervals. The walls to be tiles are thin: 25mm (tiled on both sides, so the actual thickness would be 18mm)
I wanted to use a product that is both structural and suitable for tiling, so I called up both Marmox Multiboard and Kerdi boards' technical teams. I was told that the Marmox board (20mm) would require vertical supports at 200mm intervals, which would be too narrow in this case. But the Kerdi installed some confidence - I was told the 19mm board would be sufficient. The Kerdi also comes with U-shaped stainless steel profiles, the perforated version would be suitable for tiling onto the edges (?) which also adds additional structural support. I have never constructed anything using this materials before, therefore the idea was solely based on the super strength and versatility shown in the videos. I'd be most grateful if anyone could share their experiences using the Kerdi.
For the floor, I'm using a thin 18mm screedboard Underfloor heating. The area for the mosaics is larger than usual (about 46 sqm). Initially I was thinking of covering the UFH boards with 6mm Hardibacker board with a flexible adhesive and clout nails. Now I wonder if it'd be more straight forward to use self-levelling compound instead, although my concern is that it might crack. Any suggestions or recommendations would be much appreciated.
