Hardibacker Board - Caulking and Decorting a Fireplace

[Woggle]

Hi, I've layered in some hardibacker board behind a log burner (I've checked the necessary distance from the stove).

I would like to tidy up the line - between the boards. Ordinarily I'd use decorators caulk but obviously this needs to be fire retardent. What would you suggest?

The other half also wants to paint behind the stove but obviously normal paint onto hardibacker won't be good. Any ideas?

Many thanks

 

[endecotp]

Have you read the Hardiebacker installation instructions? They say paint as you would drywall (plasterboard).

They also say tape joints with fibreeglass tape.

https://assets.ctfassets.net/dzi2asncd44t/5jwl9Z0qEgXa4alfUl57ae/ea0cf65de0fe524fa4e8913eae29f08a/HardieBacker-Installation-Guide-English-Spanish-HB1710.pdf

(Never done this myself!)