In reply to sarahjk:
Hi Sarah, i recently installed a log burner. I restored the original brickwork at the back of the chimney and plastered the rest. I looked for heat proof plaster before carrying out the work but couldn't find any. Unfortunately the log burner is far too big for the space (someone gave me it) and the plaster has cracked. How much space do you have around the burner? Mine is supposed to have 15 inches clearence, i've got 4... I'm planning on replacing the existing burner with a smaller one at some point which i think will solve the problem.
I can think of two solutions for you, strip all the plaster off the chimney, sand, point and varnish the brick work. If you don't like brickwork look you can board it with cement board and paint it. Unfortunately it has quite a rough finish so won't give a plastered finish. You can't use plasterboard as it's rated as a combustable however there is a heat resistant plasterboard. I asked the chap at Wicks if it was combustable or not, he looked at my blankly, asked all the other staff then came back and told me he didn't know... This was just for my closure plate so i bought sheet steel instead. If it is a non combustable a decent builder can make it look plastered without plastering. Good luck!
Post edited at 08:10