Is there any special bonding materials required other than cement for them to stick to each other ?

hi,is this walls or a floor your doing

best to remove existing tiles whats the substrate

That,s not a lot of info on what your tiling on?? is it wall or floor if floor they must be well stuck and the proper floor adhesive must be used if there well stuck and level and as wall you be better off if you removed them all the best

the polished grantie tiles are 2x2foot and are 1.5cm thick (very heavy) floor tiles, the reason i dont want to remove them, is becasue ive got the floor perfectly level, and rather than messing the kitchen up and digging them up i want to stick these 2x2foot pocelain tiles over them.

the floor is concrete.

can anyone recommend a suitable adhesive for the job, or what i need ?

thanks in advance.

hi staking the adhesive that you need is mapei keraquick grey flexible rapid set adhesive c2ft s1 20 kg as well as that if you took the glaze off the old porcelain tile it would bond better the best tool for this is diamond grinding cup wheel and give the floor a fast rub of the grinding wheel just so that the adhesive will bond to the old porcelain. have fun jason www.jasoncronintiling.com

thanks for yr help

your wellcome

it would be best to remove however i would use mapei kerquik mixed with latex plus if its financially viable,kerquik on its own would suffice but remember to solid bed and back butter the tiles also