wrote:
Hi,

I am installing a victorian cast iron surround.

There is currently a gap from the previous fireplace and the surround
fits neatly into the hole. However, the masonry that the surround needs
to join up to is very uneven - there is over an inch difference in
places - you can see a photo of how it looks at
http://www.isite-design.co.uk/fireplace/photo1.jpg

I realise I need to make an airtight seal between the cast iron plate
and the wall before fixing the wooden mantel.

What is the best method to fix the cast iron surround to the uneven
brickwork and how should I fill the spaces in between? I have read up a
little and seen various suggestions including firerope, fibreglass or
lime plaster but none actually explain how to make a wall flat and fix
the cast iron to it...

Any suggestion very welcome.

Thanks

GP

You don't really need "air-tight" if very-low-flow-rate will do. I'd
just pack
in fiberglass like I was caulking hull planks. Might need some tinting
to make it inconspicuous- no biggie.

J