Tile on Tile best pre pand adhesive

[larmar]

Hi Guys got a job to do but the customer insists on leaving the old tiles on the walls , the tiles are all on sound enough as I've checked them all , managed to chip one away and it seems the have been put on with a large dab of a cement based addy or mortar itself , Tiles on the wall just now are 150 x 150 and will have been on about 40 to 50 years ,as i don't normaly tile on tile I'm looking for a bit of advice on prep and what addy to use . I'm thinking a one part flexi addy , all advice welcome . Thanks guys and girls

 

[peteablard]

What is the substrate? The weight limit Is the big issue.....

 

[White Room]

If it's mortar then there a real pain to remove.......on your title do you mean pre bagged..

 

[larmar]

Hi guys the walls are brick with this Mortar /adhesive holding onthe 150x 150 ceramic glazed tiles, the tiles are 600 x 300 porcelain , but the guy was also speaking of putting on 300x600 glazed ceramic tile instead of the porcelain as i had stated about the weight restriction , the height of the wall is only 2.5m.