How should this fireplace be plastered / made smaller?

[PALLIS]

Hi,

i have just moved into a house which has this giant fireplace with large sandstone blocks around the edges (image 1). i was wanting to basically plaster the edges to make it look more like image 2 and reduce the overall size of the cavity

The only thing im worried about is if you can plaster over the sandstone as worried it just absorbs water, and also with regulations about plastering near a log burner.

Could some experienced plasters please comment on how this can be done?

thank you!

 

[windy]

I had a log burner I stalled recently...hetas guy fitted fireboard / cement board in the hearth rather than plastering... we used sand and cement and usual multi finish on the face of the wall

 

[Stewie03]

Get it tiled inside like image 2 looks better then plastering it

 

[Boycie]

Personally I prefer image 1, more character.

 

[Mouldyoldspudgun]

Why would you want to shrink it down?