Fireplace size

[bishboshbash]

Is there a standard opening for a fireplace?

We hope to install a gas fire down in the future, but the current fireplace is a mess and the builder is about to repair the brickwork and plaster.

He wants to know what size the fire opening should be. I know the flue needs to be at least 15% of the opening but the size I don't know!!

Thanks in advance

 

[chessspy]

class A fire opening,
3 strechers wide, 1 1/2 deep, 12 courses high.
or if you wish 675mm wide, 325 deep, 900 high.
this large opening is to allow a fitter to put in a fire back and dolly up behind with weak mix and hardcore.
that's all a bit old fashioned now I suppose.
The flue should be 9" liners, terracotta, and with the flange pointing down
The regs for gas fires are different, but if it looks like a class one fire opening, (chimney breast opening to the front, sub hearth etc.)then that is what it should be.

 

[bishboshbash]

Thanks chessspy for the super swift reply, so do you mean it wont be possible to have a gas fire in the future, or that changes will have to be made when it comes to installation?

I have included a pic if it helps:

Untitled

• bishboshbash
• 26 Jun 2008
• 1

Thanks again

 

[chessspy]

Erm, yes,
you can use a class one for gas, but not the other way around.
that looks alright from the pic, just jack the lintol up and pack above and tidy it up a bit.
a gas fire would often be fitted into a class one opening, and a Corgy reg fitter will/would sort any tecky bits out when he comes to fit it.
Try a bit of a paper blaze in the opening to see if it's working ok and not blocked at the top with birds nests or something.
light it and rush outside to see if it's smoking, and then rush back in to call the fire brigade etc.

 

[bishboshbash]

Lovely! Thanks for you help