/ Opening up a chimney for logburner

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Noo Noo - on 01 Dec 2017
Hi All

Thought I'd plump a question on here as I need to find answers to a problem I've encountered.

We're opening up the chimney at our house for installation of a log burner. Not a huge problem so far with opening up the chimney breast, creating a hearth etc. but I've now managed to get a good look up the chimney and found that there's a plastic duct running partially through the chimney. I suspect it houses some water pipes for the radiators and / or upstairs bathroom but I'll have a proper look later.

Stuck with what to do about it to be honest. Leaving it and installing a flue liner just doesn't sound right.

Just trying to figure out what can and should not be done at this stage.
1
Tanke - on 01 Dec 2017
In reply to Noo Noo:

That is extreme bad workmanship for fitter to run pipe through chimney stack but can be expect in British house from Jesse James.

I resolve by find out what pipe contain priority if water only drain all water from system prior to reroute pipes to clear chimney stack which is the easy pull up floor at place then use copper pipes and blow torch with right angle bend joints.
Then come in chimney consultant/trade builder to what is safe use to fill space in chimney stack.
We use block system to make chimney for log burner which heat also central radiator system also kitchen oven which is a 100% but I don't like sound of you problem perhaps OK use liners chimney expert know better.
Good luck wood burners are a great in winter.

Noo Noo - on 01 Dec 2017
In reply to Tanke:

Cheers Tanke. Typical of my luck I guess. I guess the previous owners basically decided that they were never going to open the fire place. The house originally had a garage on the side but they converted this into an additional room complete with a boiler room.

I've just managed to get to it from the room next door to check what it is etc. Basically it's an empty duct but there are two other ducts next to it with copper pipes for the heating and the upstairs bathroom. Then there's a further duct which has electricity cables. All of these are further from the flue thankfully.

So if I can pull ou this empty duct and then figure out how to block the hole across the flue all should be ok. How to get to it will be the problem. I can see me being able to pull the duct out without too much of an issue but closing the hole might be a challenge. Access from the fireplace is far from ideal. It's quite a small flue.
Tanke - on 01 Dec 2017
In reply to Noo Noo:

You problem is specialist so I would try post question to English DIY builder forum maybe this be good I know we get bit of help from our one(Not English) for a few of more simple fitting stuff of internal work and information on regulation laws example- required distance of water from electric work.
gethin_allen on 01 Dec 2017
In reply to Noo Noo:

Sounds like it's going to be a difficult and potentially expensive job. I wouldn't have anything at all running in a chimney (other than a liner obviously). The viability of ripping out all the cables and pipes you have in the chimney depends on where they can go otherwise.
Noo Noo - on 01 Dec 2017
In reply to gethin_allen:

Cheers Gethin. I think the cables and pipework will be ok provided I can remove the empty duct and fill the hole properly.

To try and explain the situation better I have the following:

75mm duct with the side just visible in the flue. This is empty.
Then working away from the flue.
110mm duct on the far side of the 75mm one. This has 2no,. 15mm copper pipes.
110mm duct on far side of the above 110mm. This has some 25mm copper pipes in it.
50mm duct with cables on the far side of the all the above.

getting to it will be the main issue I think. I can easily get to one of the ducts.
gethin_allen on 01 Dec 2017
In reply to Noo Noo:

How big is this chimney? if you have 2 X 4 inch conduits and one 3 inch conduit, one 2 inch conduit + the 6 ich flue liner which is has a larger external diameter and even larger again if you have a fully insulated liner which will most certainly be required if you have cables running in there.
Philip on 01 Dec 2017
In reply to Noo Noo:

There is a system to reline a chimney, it's expensive but considered a permanent solution (whereas steel liners are only temporary - albeit for 20 - 30 years). It involves pouring a firecement down from the top and drawing up an inflated balloon to smoother walls. That would reseal your exposed ducting. Alternatively drop a liner down and back fill with vermiculite.

Can you remove the 75mm plastic ducting and replace with something refractory?
Noo Noo - on 01 Dec 2017
In reply to gethin_allen:

It's a reasonable sized chimney which at some point in the distant past probably split into two and had fire places in the front room and the back room of what was originally a straight forward 2 up 2 down. It's very different now.

Just to clarify, imagine if you are looking directly at the fireplace the ducts are coming straight at you with the 75mm duct just poking through the side of the flue. It basically comes through the chimney and just catches the flue from front to back. This occurs in the ceiling / floor space between ground and the first floor. The others do the same but are further over and not visible in the flue.


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Ferret on 01 Dec 2017
In reply to Noo Noo:
No expert but - the duct that clips the flue is empty... then you have 2 further away that have copper heating pipes then furthest away one with electrics?

If so I'd guess that removing the empty one, 'making good as best you can and then using a flue liner would be more than adequate? Or were you hoping not to line it? If so, and it does depend on stove, but my understanding is that most stoves work best with a specific width of flue and simply plugging one into an old chimney (even if that chimney is gas tight and safe etc) may not be a good installation and may well not draw well etc.

I have a wood burner - it wasn't well fitted by prior owner, and did not have a lined flue. A small shift in where it is positioned and a relatively inexpensive job to fit a flue liner and it is much better than it was.

So potentially biting the bullet and fitting a liner may well solve your problem and make the stove installation a better job in itself. I guess the main issue is whether the other ducts will be vulnerable to any heat damage depending on how easily you can make good and how much heat transfer there is from the chimney to them, or the flue liner to them. Presumably if the ones that are in use are 'outside' of the chimney you are fine so long as you can make good... if they tunnel through the stack they may be too close and indeed I'd wonder about the strength of the stack itself?
Post edited at 15:13
Rick Graham on 01 Dec 2017
In reply to Noo Noo:

Since about 2009 any logburner or class 1 hearth needs to be passed by the local building control in the UK.

Best ask them before taking any advice on here, even mine.
gethin_allen on 01 Dec 2017
In reply to Noo Noo:

So most of these ducts are actually in the adjacent chimney or brickwork in the stack and everything is just passing through from side to side, this makes more sense. I was thinking that all this stuff was going up and down the chimney and my chimneys are only about 10 inches square.

gethin_allen on 01 Dec 2017
In reply to Rick Graham:

> Since about 2009 any logburner or class 1 hearth needs to be passed by the local building control in the UK.

> Best ask them before taking any advice on here, even mine.

I was told by a man in a stove shop that this was only the case if the burner isn't installed by a HETAS registered person.
Noo Noo - on 01 Dec 2017
In reply to gethin_allen:

Yes that's my understanding as well. I'm not at that stage yet.
Noo Noo - on 01 Dec 2017
In reply to Ferret:

Yep that's the plan I think. Just getting access to make good will be the issue. A liner was going in no matter what what. I was not even going to entertain the idea of leaving the flue as is. The house is over 100 years old. Plus log burners work their best with the correct flue size anyway.

I was initially terrified that the liner would rest against the duct and basically melt it.
jkarran - on 01 Dec 2017
In reply to Noo Noo:

Pull the empty duct out of the brick flue, block up the duct holes (someone drilled it, figure out how then gain access the same way) then drop a liner in to suit your stove or get the fitter to. If it's not plastered and decorated (or you're going to be doing a lot of making good anyway) you could chop a couple of bricks out to gain access, I had to do that so I could chop the old lead pipes out.
jk
Trangia on 01 Dec 2017
In reply to Noo Noo:

Think seriously about the long term advisability of installing a log burner. With the drive to clean up our atmosphere and reduce air pollution globally there is the possibilty of their being banned, along with other forms of solid fuel heating, in the not too distant future, in the same way coal fired power stations are being discouraged, and that diesel and eventually petrol engines are.

I was brought up in the days before the clean air acts, and during the terrible London smogs, and it wasn't all that long ago.

Whist I realise that it's not yet a major problem. the rate of change is accelerating, and a lot could happen over the next couple of decades, including, of course, on the plus side, improved methods of filtering out harmful carcinogens and other undesirable emissions.

I'm not saying don't, just be aware. You may not want to throw a load of money at something with a limited life......
3
Spartacus on 01 Dec 2017
In reply to Trangia:
Thanks I’ve just bought one!
I understand the new ones are of a much higher standard in relation to emissions.

Mine has a second set of vents which apparently burns all fuel left in the smoke and is designed to burn hot.
When up to temperature the smoke is non existent.
Trangia on 01 Dec 2017
In reply to Spartacus:

Sounds good - see second half of my penultimate paragraph.

Andy Morley - on 02 Dec 2017
In reply to Philip:

> Can you remove the 75mm plastic ducting and replace with something refractory?

Hard to imagine a situation were it wouldn't be easier to re-route the services if it's only copper pipe involved and maybe the odd cable. But I suppose that if you have to get someone else to do it, that might change things.
Toerag - on 02 Dec 2017
In reply to Noo Noo:

I had 4 chimneys lined with a variety of methods last year, will be back with more info...
Timmd on 03 Dec 2017
In reply to Trangia:

http://www.poujoulat.co.uk/catalogues/domestic/Leaflet_top_clean_PF_2014.pdf

I'm thinking of getting one of these electrostatic particulate filters fitted next year, for my wood burning stove. My conscience doesn't like that the particulates from my smoke get blown across over Sheffield and hang in the air in the smog over the basin where less fortunate people live.
2
johncook - on 03 Dec 2017
In reply to Noo Noo:

It might be worth paying a professional as insurance these days can be a bit picky in the event of anything going wrong, eg a leak of flue gasses, a chimney fire etc. The pros know what is legal and safe, and should be certified for the installation.
1
Toerag - on 03 Dec 2017
In reply to Noo Noo:

I'm back. About 3 years ago a fist-sized lump of granite came down the main chimney of our 1895 house so we had a chap come round and stick his camera up both downstairs chimneys - much of the mortar was well-receded and the whiffs had disappeared (whiffs are the dividing walls in the stacks) so they needed re-lining. The options we had were as follows:-
1) Drop a SS liner down the chimney. Cheapest, but doesn't last in a marine environment like here so he refuses to fit them. Property developers use them because they don't care about the long term like a homeowner does.
2) CICO cast concrete - lots more work, but lasts 'forever' and stabilises the structure of the flue if it's really bad. They drop an inflatable sausage down the flue, break into the flue through the chimney breast or gable at every bend in the chimney and fit spacer collars, then fill it up with lightweight refractory concrete. The spacer access holes simply have the bricks/stones put back into place behind shuttering as the concrete level reaches them and the lining material bonds them together. The whole process is done over a number of days depending on number of access holes. When the concrete has cured the liner is deflated and removed. Not suitable for large open fires because the flue is reduced too much. Making a 5 or 6" flue for a woodburner is no problem.
3) Furanflex composite liner - this is an uncured fibreglass resin sleeve that's lowered into the chimney and inflated with steam which cures it. It's carefully sized to fit the flue so it forms a fibreglass 'skin' on the inside of the flue. We had to have this for our large lounge open fire because the CICO liner would have reduced to flue too far. The throat of the hearth was faired up into the liner with mortar/render, previously it had simply been a massive rectangular void. If you have a chimney fire with one of these liners it needs replacing or re-lining over the top of what's left.
All methods require scaffolding on the stacks and the pots removed to fit them. We had both flues at one end of the house CICOed, and Furanflex and CICO at the other end of the house for £10k, but that's Guernsey prices which will be higher than UK prices. We had the upstairs flues CICOed to stabilise them, they're now technically too small for the small open fires in the rooms but no-one's going to use those fires ever. Full exposed stack rebuilds with lead trays would have added significant cost, and as the exposed stacks were in good condition and we don't suffer damp in the house due to the wind howling through the felt-less loft and drying out the stacks I simply re-pointed them and gave them a good soaking with silicone water repellent.
Hope that helps anyone reading this.
LeeWood - on 03 Dec 2017
In reply to Noo Noo:

Alternatively you could close the existing chimney with its installed pipework and install a new inox chimney. This holds advantages:

a) get the stove out in a more central position - better for heat dispersion
b) more heat into house (2nd level ?) - radiatew with height
c) (possibly ?) smooth pipe lining easier to clean / will not hold soot as a flue liner

I've installed 2 such pipe systems; expensive materials but lo maintenance after.
Lusk - on 03 Dec 2017
In reply to Timmd:


> I'm thinking of getting one of these electrostatic particulate filters fitted next year, for my wood burning stove. My conscience doesn't like that the particulates from my smoke get blown across over Sheffield and hang in the air in the smog over the basin where less fortunate people live.

You were thinking about this system about a year or so ago. I seem to remember it was ridiculed at the time.
You're still thinking about it?
Timmd on 03 Dec 2017
In reply to Lusk:
> You were thinking about this system about a year or so ago. I seem to remember it was ridiculed at the time.

> You're still thinking about it?

It was ridiculed by some on UKC, but it (or similar products) are required in some areas in Europe, which is more worth taking notice of than unknown posters on UKC I would think. ;-) Any reduction in air pollution is a plus.

With my wood being scavenged (I live next to some woods), it's got a small carbon footprint in terms of energy used to get it in a burnable form, the only other thing is to reduce any pollution in it's burning.
Post edited at 23:03

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