Considerations for false Chimney breast for gas fire

[ChrisJ]

We are looking at having a new gas fire fitted in our lounge. It already has central heating and so is more of a feature than a heat source. There is no chimney breast to mount it in. The current gas fire is a "free standing" one on a 15" marble hearth. I really like the Style of ths fireplace :

is extends 10" back from the front facia. As our walls are probably only 1/2" of plasterboard and 4" blocks we have been told that the best way to install is to build a false chimney breast as this minimises heat loss into the wall cavity as ony the flue goes through the cavity not the whole fire box.

I have two questions:

1) Does this type of fire require more work to fit than a traditional floor level fire and mantlepiece affair that has the same depth behind the facia? The floor level fires are the same depth but are mounted on the "front" of the fireplace so extend back into th eblockwork less but as the fireplace only adds a couple of inches surely both would extend right into the wall cavity. I want to try and avoid loosing heat into the cavity. 2) Do I still need a hearth? If I need a false chimney breast and a hearth it will intrude into the room too much.

The fitter giving us a quote suggested building a false chimney breast

10" deep out of 2"x2" and plasterboard to house the new fire which would break up an otherwisefairly plain wall so I've nothing against this other than it adds to the cost. This would also hide the gas pipework. Having put up stud walls before I think this is something I could do but I'm not sure if there are any special arrangements required to allow a fire to be fitted.

Is it possible to put vents in this false chimney (on the sides) to recover the heat from this space back into the room?

We have a plumber coming in to fit a new boiler so I could ask him to cap off the gas for me to remove the existing fire.

Anybody got any thoughts?

[John Cartmell]

Before you do - we recently removed our gas fire because its presence made furniture arrangement very limited. far better without! ;-)

[Ed Sirett]

The info shows that these appliances need a flue. The chimney will need to be real even if the chimney breast is false!

[ChrisJ]

outside wall) just as it would without the false chimney breast. I wanted to install the chimney breast to minimise the hole in the inner block wall of the house which would be reduced to just the flue pipe rather than the hole of the back box of the fire. Putting the hot back box of the fire in the cavity between the house inner and outer walls will loose a lot of heat directly into the cavity, putting hte fire in the room (albeit in the faux chimney breast) and just the flue in the cavity a) reduces heat lost from the box to the cavity when the fire is on and b) reduces heat lost from the room when the fire is not through the lack of cavity where the fire is.

Any thoughts?

CJ

[Ed Sirett]

I followed the link and it lead to a page showing fires using Class I and Class II flue systems. No mention of balanced/powered flues.

[ChrisJ]

Ed Thanks for your thoughts on this one. The fire is now ordered and I'm going to build an 8" (ish) "chimney breast" from teh metal stud wall stuff and "fireboard".

My next related question is :

Is there any way to stop teh drafts coming in the flue when the fire is off? Can you get a valve or something similar that closes when the air flows into the house but opens when the fan is blowing out? Our flue will be "upstairs in the gap between us and next door and the wind rips through the gap.

On a similar not is there a way to "quieten" the wind noise on the flue? Our current one has a tendency to "whistle" when the wind is strong. Again with it being upstairs (house on a hill (going down to the back), lounge at the back at "first" floor level.

Any help appreciated.

ChrisJ

[Ed Sirett]

I'm really confused as to what type of fire you are trying to install. In particular what type of flue is required with it.

I suggest strongly that you get professional help at this point.