Looking for advice how to tile waterproofed bitumen steps

[Dontiler]

Hello guys,
I'm looking for advise how you guys deal with waterproofed bitumen steps outside. We need to lay Victorian tiles on them, just not sure what to do with this waterproofing.
What would be your recommendation for this project.
Thank you for your help in advance.
Don,

 

[Dontiler]

If you see just the top section of steps is waterproofed

 

[Flintstone]

A very very good clean by whatever means you usually do. Remove as much of the bitumen as you can if there’s any loose. Prime the rest with prime plus grip.