Flue opening

Hi I was wondering if anyone on this forum would be kind enough to provide me with some information about the required measurements of a flue opening. Basically I am decorating my lounge and the present opening to my flue measures 13" wide by 22" high and goes back 13". Which I think is a very small opening. My wife wants a new gas fire which will sit back into the recess. Does anyone know what the required space is that regulations say are required. I think the opening will have to be altered and also would it have to be lined with what I think use to a fire back. She has already been to a shop and brought back several brochures that show lots of pretty pictures of fires in their surrounds but looking at them they give their overall dimensions but no information about their inset depth for gas fires.

Best to pick which fire you want (dont buy yet) go to there web site and download installation instructions for that specific fire. Common dimensions if your fitting a hearth and back plate are 610mm high, 505mm wide and 210mm deep, this is for fireplace opening, also i would get a gas safe engineer (with fire quals) to look first with some recommendations.

Before doing anything,get the chimney swept and have a smoke test carried out.You don`t want to get the fireplace altered only to find the chimney is faulty.

The opening is normally 22" high FROM the hearth by 16" Wide. But don't go messing about trying to sort this out. go back to the shop, explaint to them the situation, take some pics if possible. At the end of the day, if the shop is run by an experienced fitter, you choose the products, and they make everything right to install. Actually fittting the fire is sometimes only a small part of the job.