laying porcelain tiles over u/f heating

[carl58]

HI MY NAME IS CARL I AM ABOUT READY TO START LAYING PORCELAIN FLOOR TILES IN MY KITCHEN AND WOULD BE GRATEFUL FOR ANY TIPS/ADVISE THE FLOOR BASE CONSISTS OF BLOCK AND BEAM OVER LAYED WITH OSMA UNDER FLOOR HEATING[HOT WATER] THE LATER BEEN LAYED BETWEEN 35MM BATTENS AT60CM INTERVALS 18MM T&G PLY SHEETS HAVE BEEN SCREWED INTO THESE TO PROVIDE THE
BASE FOR TILES THE TILES ARE FROM B&Q[CHINA]!! 40X40CMS THANKS

 

[gcol]

I would say that 600mm centres is too far apart - I would go no more than 400mm centres with 18mm ply. 25mm ply is the way to go and make sure it's WBP ply.