We are lucky enough (or unlucky depends how you see it) to have Topps Tile admit the black gloss porcelain tiles laid have a fault & they are covering the cost to replace. I am a little concerned that they are trying to cut corners as the old tiles have been removed & they are leaving the adhesive in place adding a scree (2mil thick) then adding more adhesive ontop of this. The gap underneath our door is only 5mil (PVC so cannot be trimmed) so technically the most they can lay adhesive & scree is 3mil?! they wouldn't let us have the same tiles again so we have had to go with another sort which are 1 or 2 mil thicker anyway. What is the best way of getting the old adhesive off the floor (it's concrete underneath) as unless anyone else has any ideas on how these new tiles can be laid properly & so we can actually open the door (checked the adjusters on the door & it is as high as it will go already) Thanks

SDS drill with chisel action and a chisel bit is the boss of getting up old adhesive.

If a floor is perfectly perfectly mirror flat, you could get away with a 6mm notch trowel, but for most floors I use 8mm-10mm.

Hope this helps.

s.d.s gun ....and alot of elbow grease..

You would also need surface protection on your kitchen doors to protect them against any chipping/scratches if using an sds for breaking out.

As above, there is no easy way of getting it up (if it is stuck down properly), just good old fashioned sweat and elbow grease.