Opening 1920's fireplace

[john.s]

Hi,
I'm new to this forum and have looked through many postings regarding the opening up of fireplaces, so I'm sure this will be a tired subject for many of you - but here goes anyway!
I am in the process of opening up a fireplace in a 1920's purpose built flat, it's on the first/top floor and is the main fireplace, being in the living room. I intended to remove the plaster then see what was what regarding the brickwork and lintel, but as it had been cemented over before plastering the render just would not come away - so I carefully removed a breeze block at a time, until I got to the bricks, at which point I have stoped.
There is a cast iron back boiler, which has brick chimney sides built right onto it - although I doubt it is supporting anything. There was a lot of ruble filled in all around it which I have removed.
I want to have the fireplace fully open with the brick showing and either a dog basket type grate or a multi fuel stove sitting in the middle.
My questions are many...what should I do with the bricks either side above the stove? Do I take them out to try and reveal quite a large fireplace or are they part of the original structure?
Will I find a lintel a bit further up if I keep going? Or would there have been a brick arch lintel that has been removed prior to breeze blocking?
What dimensions should I expect the fireplace to be? Have I taken too much out and urgently need to fit a lintel? Or should I try going up a little further?
I don't want it all to collapse but can't really stretch to a proffessional for help at the moment!
Any ideas much appreciated - I hope the picture came out!
john swaine

 

[john.s]

Sorry, here's the picture...

 

[Lime]

The picture is not very clear but I would expect a small lintel to be directly above the mouth of the fire usually of steel.
There is often a brick arch/concrete/steel lintel higher up but not always.
You need to take off a bit more cement without removing any more bricks to check further.
My concern would be the back boiler.
It is quite probable that it is still full of water and connected to pipework which may still be connected to a hot water tank somewhere.

 

[john.s]

Hi Simon,
Thanks - I just took off some render and have gone up to about 1.6m from the floor but no sign of anything at all lintel like. As it is cement it is very hard to remove even with angle grinder and sds chisel.
I have been in the attic quite a bit - no sign of old heating system/water tank as everything was re done in 1988 (presumably when the fireplace was covered up) so I am not expecting the pipes to go anywhere much.

I wonder why the wall has a thick cement render over it and wether prevoius builders took out the brick arch or lintel?
If I take the boiler out will the large stacks of bricks either side (that sit into the fireplace opening) come crashing down?
There is a boarded over extension to the right hand side of the chimney which carries various pipes to down stairs, I'm going to open that up a little - I expect to see the old iron boiler pipes there, prolly just cut off.
cheers,

 

[Lime]

The builder/plasterer used cement because that is what "modern" plasterers use, unfortunately.
I find it gives a wall an unpleasant cold feel and almost an open invitation for condensation to occur if the air is damp.
As for the bricks, I doubt those that are on either side of the backboiler will fall but I wouldn't guarantee the solidity of anything to do with fireplaces.
Just make sure when you have opened the area up enough that you make some support for all the bricks for your own peace of mind.
The backboiler is still very likely to have dirty water in it even if it has been cut off.
Sometimes you might find in the side part that is enclosed (boarded over extension) a drain cock and a pressure relief valve.
I'd be prepared for water to be still present.

 

[john.s]

Hi once again - just to give everyone an update, I have now removed the old cast iron back boiler - cut through the pipes ok with an angle grinder - and yes there was some water still in there!
I now have a clear fireplace as hopefully a picture below will show...

But I do have quite a few questions I'm afraid!...
1/. I'm still concerned about the bricks either side - they form a venturi style flue I think, and were previously supported by all the ruble that had been packed in around the cast iron back boiler. They do not appear to be interlinked to the main chimney sides, although I cannot be certain of this. They allow the flue to widen up each side, before it goes off to the left at an angle. If I put a fire basket below, will the sticking out underside edges of the bricks not get too hot? Or can I guard against that by angling them off a bit? Or using quite a small fire basket? Should I put brackets to support these bricks?
2/. I am thinking of putting a lintel across the front - I have seen a 900mm concrete lintel in Wickes and as the fireplace opening is 700mm I think this would do - but should I get a special fireproof lintel or one with a sloped inner edge? Or can I just cut a sloped edge into the one from Wickes?
3/. What height should I make the opening? The width is 700mm so I was thinking of putting the lintel at the next course of bricks up (in the picture), leaving about 800mm or so opening from floor level.
4/. Can I render the insides of the fireplace - and if so what with? The bricks are pretty poor.
5/. The hearth is concrete with some bricks still on it - the concrete is a bit broken - should I build up the hearth height with cement or bricks or something?

I'm sorry to ask so much! The rest of the room is coming along now and I can't put the fireplace off much longer! I am thinking of getting advise from a chimney sweep anyway.
I'll do another post soon regarding how my plastering of the entire ceiling went!

Many thanks,
john s

 

[MdB]

I'm not an expert so won't comment. I would suggest that you read the following though (very exciting read):
http://www.planningportal.gov.uk/uploads/br/BR_PDF_ADJ_2002.pdf

 

[john.s]

Thanks - I've just been through all of that document. I have booked a chimney sweep for next week who will sweep the chimney and test and inspect it. Hopefully he can offer advice on how to finish the fireplace, if the thing is at all viable.
Will keep everyone posted!

 

[john.s]

Hi,
Just to update those that are interested. I had a chimney sweep round who answered quite a few of my questions and verified that the chimney is all clear - a little piece of mind at least. I have nearly finished taking out all the bricks either side/above into the chimney to reveal the full size of the chimney itself - I was told this would give better draw and the old brickwork was there for the specific fire that was originally fitted. (The chimney sweep said as the bricks were not really attached to anything that heat from the fire could cause them to fall).
I have also prepared for a concrete lintel which I will cement in today. The fireplace base itself I am going to build up by a couple of inches (with cement or brick?).
I have guest at the height of the opening, and the sweep sais if it does not draw well I can lower it a bit, I won't re do the lintel, just add something under if necessary.
So, I am nearly ready to render the fireplace - I want to render all the exposed brickwork, and was thinking to go up as far into the chimney as I can reach, as the brickwork is quite rough and gappy and I thought it would be safer to cover it all - the sweep sugessted a render mix but I forgot - I'm sure it can be found on here - does anybody know off hand? I think little cement and quite a lot of lime so it's soft and doesn't crack?
Then there is the question of tiling - I was thinking to do a tiled hearth going all the way back into the fireplace so would need something heat resistant. I have been looking at natural slate tiles in Wickes - would these be any good? Or they also have small red quarry tiles which I rather like - or can only special tiles be used?
Getting there, slowly...