I have posted about this ongoing job before. Basically I have taken down an existing p/b chimney breast to remove a 4 in flu and had a 5 in flu installed. I now need to bebuild the chimney breast. Previously it was quite deep do no problem but now the front of the chimney breast is determined by the depth of the combustion box that the coal affect fire will sit in. This is not much deeper than the 5 in flu so I can't have a a 44mm noggin going across the front of the chimney breast as there has to be a 2 in gap between the flu and any combustible material. Bearing in mind that the chimney breast will be about 54 ins wide this seems too large a gap to span with plasterboard, even for a chimney breast that wont be leaned against. I have thought about bridging the chimney breast with something like dexion to offer support to the p/b. Anybody got any other bright ideas or done anything similar before? The guidelines are no combustable material within 2 in of the flu and I think 18 in of the combustion box. The combustion box isn't a problem though as it will have the fire surround in front of it.
Kevin