'Skiming' over render??

[Setone]

I have a internal rendered wall in my conservatory. I want to tile this, but to flaten it of i was going to skim over the original wall with a thin coat render, platering sand cement mix.

is this a good idea? its a single skin wall btw

 

[roy c]

If your tiling it and it only needs a thin skim , why dont you skim over it with tile adhesive?

 

[Setone]

some parts of the wall have some deep dips around 10-15mm, and are quite large.

Render is cheaper then tile adhesive