Tiling on asphalt screed?

[White Room]

I'd be using sbr with a cement slurry for a key.

 

[DHTiling]

I would use insulation boards if using ufh..

A slurry coat is SBR mixed 50/50 with cement or rapidset.. and the floor needs to be as clean as possible, so a wash with sugar soap will suffice before slurrying.

 

[H.I.S]

I have got 6mm insulation boards already for the job as i cant go any higher, i was going to try and key/scarify the surface what do you think? so i can use cement or rapidset mix with sbr as slurry coat, do i wait till slurry is set before fixing the insulation boards down with spf? i had got some instarmac ultra prime it fp to use as an acrylic primer thinking it would do the job, glad i asked the question on here first.

 

[The D]

I'd get rid of it

 

[Ajax123]

melting and smelling of bitumen is pretty conclusive I would say. Magnesite would just get hot and with a blow torch would give of a bright yellow flame. As previously said though it don't look like asphalt. My opinion use epoxy to seal whatever it is then use uncoupling membrane.