Advice on type of render to use

[pilgrim]

Hi,

I have two old fireplaces in my house that I want to skim.

 

One is in the master bedroom and I have removed the old open coal fire and plastered the walls, but I am not sure what would be the best product to use to make the floor level again. It will probably be carpeted over so not worried about the look. Is concrete the best product to use here?

 

The other one is in the living room and I want to put the wood burning stove back in place but not sure what is best to use to skim the old bricks as it will need to cope with the heat from the stove. I am thinking that I will then paint this finish rather than tiling behind the stove.

 

Any advice would be greatly appreciated, thank you