Torn down concrete wall, how to even out the ceiling? ..Also question about flooring.

[LinusW]

Removed part of a lightweight concrete wall over the weekend. What is the smartest way to even out the ceiling where the wall was? Now there is an indentation in the ceiling of maybe 5-10mm. What's the easiest to use? Mix concrete? Gypsum plaster? Something else smart?
See picture:


Question 2.
Same room, planning to install new flooring. It will be laminate click flooring.
The old floor is easy to tear away but they apparently glued it to the concrete floor with tar. The tar is not easy to remove at all.. I suspect I might have to rent a heavy-duty floor sander if it has to be removed. Do you think I can leave the tar in place? It doesn't create much height. Maybe the foam underlay beneath the click flooring can handle this? What do you think?

 

[Vante]

http://www.ardex.se/fileadmin/ardex_se/Broschyrer_PDF/inf_a45.pdf

 

[LinusW]

Thanks for the tip, seems appropriate

Does anyone have an opinion about the floor? Do you need to sand down the adhesive before laying the foam mat under the floor?