half concrete / half boards

I want to lay ceramic tiles in a kitchen that is half floorboards, half concrete. I therefore need to lay plywood over the boards - not sure what thickness, some recommend only 6mm but others min 12mm. This will then raise the level of the boarded area above the concrete (either 6or 12mm). Should I continue the plywood over the concrete half or build up using a levelling compound?

Can you not take the floorboards up in the kitchen area then renew with exterior plywood & leave the old boards under the kitchen unit?

You can use fast flex adhesive on the floor boards and a standard adhesive on the concrete. With fast flex you don't have to over lay with ply therefore keeping the floor level even .

P.