Hi, I've just signed up here and would greatly appreciate some advice from what comes across as a very friendly and knowledgeable board..
I've got a job that I've not attempted before (although done a fair amount of "standard" floor and wall tiling previously on solid substrates), I want to make a tiled kitchen island worktop finished in 10 or 12mm thick dark/black granite tiles, overall size approx 1600x900mm with minimal (maybe a couple of inches) overhang beyond the supporting units.
What is the best base material to use, I was thinking 2x18mm MDF for example or maybe topped with ply? Should I then seal the surface first or is there a suitable adhesive to go straight on the MDF/ply? I've been reccomended to use a a dark epoxy based grout to be hard wearing and hygeinic, is this what would be reccomended here? What kind of gaps are required, I'd prefer to have minimal gaps, but appreciate that a certain amount of gap is generally needed for the grout to work properly. Is there an alternative sealant that could be used instead of grout, and butt the tiles closely together?

Sorry for a long post, and any help much appreciated
Cheers
Rich

What ever you use for the sub base I would cover with tile backerboard before tiling.
Epoxy is available from Mapei, one of our sponsors. The joint should be 2mm really but as long as the maker of the epoxy grout says it can be used in 1mm joints then I would prefer that but its not technically correct if you understand.

As above, use a cement board for your tiling surface. Much more practical for tiling to and won't get deformed if it gets a bit damp.

Hardibacker 500 would my choice of base, this will aslo be suitable for the 2 inch over hang if you frame it for the drop..

These videos will help..

thanks guys, great help!
Any reccomendations for adhesives? Does the backer need bonding to the substrate board, or is screwing sufficient?

Use adhesive as in vids.

ah ok Dave, I'll watch again with sound when I can get at my other PC, probably loses a fair bit in translation without sound! :-)