How to prevent soot from showing through plaster ?

[Alfielander]

I’ve got a job upcoming skimming the inside of an old Coal fireplace and heard that soot can show through of the skimming, How do I prevent this !?

 

[themucky1]

Don’t skim it! Simple

 

[Alfielander]

Don’t skim it! Simple

There’s got to be away, they want it as a feature

 

[S a plastering]

There’s got to be away, they want it as a feature

Surely you will be floating it out if brickwork that said I would sand and cement it then skim

 

[Steve Brown]

Check old posts there's lots of options.
If plastering use victus system or fire rated cement board options.

 

[ChrispyUK]

Grind it off, salt neutraliser, then run for your life.

Always think it’s better to sort out and re-point the brickwork.

 

[Jhonsteve111]

I’ve got a job upcoming skimming the inside of an old Coal fireplace and heard that soot can show through of the skimming, How do I prevent this !?

To stop soot from showing through, apply a shellac-based primer or stain block to seal the surface before skimming. This will prevent any stains from bleeding through the plaster.