I have had some feedback from the forum which was v helpful - basically the tiles I have taken up had hairline cracks in - found bitumen underneath - what to do ? BAL say they have no products to recommend - schluter dont like the idea of their decoupling membrane with small mosaics. Dave suggested expoxy primer -can anyone tell me the advantages of this? Still scratching my head - any ideas other than taking tarmac up. Room is 3.5sqm ensuite with 'wet room' shower. Cheers

Am I right in assuming tha the bitumen forms part of the previous tanking procedure and is the whole room fully tanked?
Are you looking to fully tile the floor in travertine mosaics?

Have you considered fixing Hardie backer boards over the bitumen/sealing the joint to the tray area/increasing the falls to this new height/flexible fast set adhesive skim to the outlet/fixing new mosaics.

Timeless John.

there is no evidence of tanking and no moisture had got under the original tiles. floor area is 4sqm and yes all to travertine. not so keen on hardi backer boards and think I will go with epoxy primer and flexi cement based addy