Chimney Flue designs? what can i expect to find?

[jungle_jim01]

The restoration planning continues...thanks to everyone's help so far...early 1800s Yorkshire sandstone building... Downstairs in the lounge i have a nice victorian looking metal fireplace surround and small fireplace. The flue is built into the gable of the house with no defined chimney breast. Before next winter arrives (sorry for mentioning winter!)...i'd like to open up the fireplace and install a woodburner. Thing is i'm not sure what to expect to find behind the fireplace. ie; will it have been built larger and filled in more recently (fingers crossed!) or will i need to chop out some of the main wall (argh!) ...i guess the only way is to know is to start removing the plaster but trying to live in here at the same time so any insights would be helpful

 

[robgil]

any pics?
if you stick your head up the chimney can you see a larger void?

please dont get your head stuck up the chimney.

 

[jungle_jim01]

Thanks for the reply. Attached is a photo of the fireplace...interestingly....there is a large void behind...unlike a newer fireplace in a victorian extension which has a narrow flue behind the fireplace. Also...I've reached in with my phone and taken some photos of the back of the fireplace in which it looks as though the original fireplace was much larger and has been blocked. You can see a sandstone lintel and what looks like a brick support...excited!!

Also now contemplating whether i can actually knock this out myself as there shouldn't be anything structural!?

 

[jungle_jim01]

ooops...didn't think the images would be that big....if you right click, then select 'open in new window' you should get a better view...also may need to turn your screen on side for one of them!

 

[Penners]

You should almost certainly find that, when you've removed the existing fireplace, you're left with a larger firehole, with a supporting lintel across the top. But, as with any investigative procedure like this, just take the job very steadily. Dismantle the fireplace a step at a time, and check the integrity of the structure at every stage.

Judging by the lower photograph, the existing fireplace is quite small. And it's impossible to get any concept of scale from the upper photo. So it's very hard to say whether you'll end up with a firehole large enough to house a woodburner.

Of course, you don't have to place a woodburner within the chimney. You can build a projecting hearth and have the stove freestanding against the wall (provided the wall is masonry). This is best achieved with a rear-flue stove.

Incidentally, to avoid the problem you've had with your pictures, it's best to limit the physical size of posted images to about 800 pixels.

 

[jungle_jim01]

Thanks Penners...i hadn't really thought about bring the stove fully into the room. I'm still hoping the original fireplace will be large enough. The opening looks like it will be approx 1.1m

 

[Penners]

High or wide? Either way, that's not particularly generous, but should be do-able. It's just a qeustion of finding a suitably sized stove.

Be sure that you insulate the flue within the chimney to minimise acidic condensates.

 

[jungle_jim01]

the measurement is width...only going to be a small stove so should be ok. the flue isn't in good condition so we're looking at thermocrete lining in the hope it'll both line the chimney and fill some gaps.

 

[Penners]

Just one thought, Jim. Is your house listed? If so you will of course need LBC before you take the fireplace apart.

 

[jungle_jim01]

good thinking....we're not listed so shouldn't be a problem

 

[chuckey]

My 1800 Wensleydale cottage has it's flues built into the wall thickness (24"!). when we moved in there was a 1950's fireplace with a tiled surround. One Sunday afternoon, I hacked off the plaster above the fireplace to expose bricks , then went higher to expose the original stone lintel. We actually had a 16" wide fire place with a brick surround with a thin tatty stone lintel, topped with a different version of brickwork (Victorian?) then the Georgian big lintel. In the end we had a hole 40" wide, 50" high and 18" deep. This gave an impressive surround for our log burner when we built a new stone mantlepiece and surround.
Frank

 

[jungle_jim01]

wow! sounds amazing

 

[robgil]

put plenty of dust sheets and cardboard around , its a very very messy job. i took out my lovely old 'period' fire place a while back. what looked like a reasonably easy job turnd out to be an entire wall removal. the fireplace had also been filled with earth , about 5 barrow loads.
try to do it when the boss isnt home.

this is what we started with,

not sure what to find , with the help of dave we peeled the cement plaster away from the fire place but found it also concealed the old daub stud wall behind each side of the fire place.

and in the end we uncovered a , what we are told is a Georgian fireplace and the original gable wall either side of it.
it made a huge mess but i was lucky i think to find what was behind it all , except for the two completely rotten sill plates and disintegrated brick plinth.

still , well worth it in the end.

 

[AMc]

Rob's fireplace looks fantastic, but put it in context of some of the other work he's been doing before you begin wielding the sledgehammer

In your position i.e. with a plan and an accessible flue, in summer! I would contact a couple of HETAS registered installers to discuss your options on lining & insulating the flue (probably necessary) sizing the stove (too big is worse than too small if this is a secondary heat source) and positioning it inside or in front of the chimney.

If you fit a stove inside the fireplace underneath a chimney without a register plate a great deal of the heat you produce will convect up the chimney and you'll only feel the benefit of the radiant heat from the front of the stove. 3 sides of the heat radiated will warm the chimney stack which will mean it takes a long time to warm the room. When the stove is not lit it a lot of your central heating will go up the chimney, even if there is a sealed flue in there.

If you can bring the stove into the room with the flue bricked in behind it then you will get a much better output from a smaller stove. This was advised to my parents who had there hearth extended slightly and the stove put 'in the room' rather than in the chimney as they'd originally planned.

Also consider an air source - if the stove is over 5kw then you'll either need an airbrick or another form of external air source regardless of how draughty your room actually is.

We have an old stove installed in a reopened Georgian fireplace. The stove is too big for the room which means you can get the room to +28C in mid winter without trying - which sounds lovely until you realise that having it sealed up and burning as low as you can isn't great for the flue. When we were having problems with our new heating last winter we had a register plate fitted which increased the room temp by +1C immediately (without lighting the stove) - I hate to think how many litres of oil kw of electricity had been burned to warm that chimney before we did that.