Shared Class One chimney/flue (?) & hole in the wall gas fire installation

[spantik]

I am getting to learn a lot about fitting an Atina HE 'hole in the wall' BFM Kinder gas fire but I need more HELP please? I have talked to lots of installers (Gas Safe registered) about this job but I'd be glad of your opinions on one particular issue - the flue?

I live in a modern (1978) terraced property. There are 4 homes joined together with a flat roof across all four and 2 brick chimney stacks. I think I 'share' a chimney stack with one adjoining property. I think you could call it a Class One chimney/flue but, not having been on the roof recently, I don't remember the stack. Should there be two separate tops - one for our house and one for my neighbours? When the houses were built we all had Baxi 551 back boilers and Baxi gas fires. I have very recently updated my CH system and the back boiler is still in situ but decommissioned. The gasfire still works.

Now that we can, we want to change the gas fire to the Atina. This would fit almost fliush to the chimney breast using all of the opening for the Baxi fire and a little bit more. As I understand it the installation instructions for the fire don't mention the need to line the flue. They say 'the appliance is designed for use with conventional brick built OR lined chimneys......" All flues must conform to the following minimum dimensions:
Min diameter of circualr flue - 125mm. Minimum effective height of all flue types - 4 metres.

- Do you think a house of the date (1978) and construction I have described will fulfil these specifications?
- Do you think we need to line the flue even if the necessary tests are carried out successfully?

My Main Question is THIS:
When our new neighbours moved in a few years ago they lit a fire in their 'grate', this being exactly the other side of the party wall from our gas fire, and we smelt smoke drifting in behind our gas fire in our house! Scary!!! We told them about it and they stopped using it. They've taken the grate away.

- Is their a possibility that we might share the same flue? Could this have been legal in 1978 when the houses were built? I can't imagine it ever was? Surely if that was the case there is a possibility the fumes from our gas fire could be entering their house or is it ducted way up the flue and not possible?

HELP please!!! What do you experienced people think? I didn't need to learn much about flues to teach kids with autism......

Obviously whoever fits the new fire will survey first but it's always good to be well informed and a few steps ahead. Thanks heaps.

 

[bennygas]

hello,

first, I think the first thing to address is your concern about the integrity of your flue. you're quite right, if in the past you had this situation where smoke was evident in your home from next door - this would suggest that the flues of your home and your neighbour's communicate in some way or other. this isn't what you need at all. I would say, and I can only go on the info you've given, but I think there's the possibility that an unsafe situation could exist with the installation as you've described it, whereby you could inadvertently be exposing your neighbour to risk through the use of you fire, and if your neighbour has any open flue appliance (or indeed some other type of heat producing appliance) connected to the adjacent flue on their side of the party wall, they could likewise be exposing you to an unsafe situation. A lot of the risk is going to depend upon the nature of any communication between the flues, their performance, and numerous other factors including weather/climatic conditions as well as the/any appliances involved. I would say that your key priority at the moment is to get this situation investigated, and then either resolved or made safe. In short, it sounds very much as though you really need a diligent RGI to attend and have a good look at exactly what is going on there.

In terms of the suitability of your flue, well, I'm afraid that's going to depend upon the nature of any problems found with your existing flue. Given that you've got an old baxi in there, the chances are you have a 5 inch metallic liner passing up through the chimney, so one would like to think this bodes well for the chimney's suitability on size grounds. Obviously though, it does seem like there's an issue with integrity. As a possible work-around, and it would depend very much on the state of your chimney, it may be feasible, depending upon what the appliance manufacturer states as to the suitability of different flue systems, to install a flue gas collector box along with a new flue liner to provide a solution. But first things first, get it checked out by someone who knows what they're doing, and who can see what it is they're dealing with - none of us here on this website can do that via the internet. What area are you in - there may be a someone on here who's local to you.

 

[spantik]

New gas fire installation & assessing integrity of present flue. HELP!

Please persevere and read to the end of this post. The sting is in the tail!!

Thanks for this detailed comment which is more or less exactly where I'd got to. The main issue is finding someone competent to report on any problems that exist. Help again please! I have had the gas installation tested & serviced every year for 35 years but I guess leakage could have been missed? Could it?

I live in CV10 0SG ie north of Coventry in N Warwickshire close to Tamworth, Hinckley, Nuneaton, Burtin on Trent and not far form Leicester, Coventry even Birmingham, but that's further.

Can anyone help with a comprehensive assessement of my situation please - or recommend somewhere I can find out? What kind of qualification do the engineers listed on the Gas Safe website need to possess so I can contact soneone local?

I have found a member of NACE in S Warwickshire (National Association of Chimney Engineers) - would they be able to report?

After posting this I found out that any house built since 1965, by law, must have an inner lining to protect the chimney structure so can I assume there is a flue liner in situ as you suggest?

Thanks again.

hello,

first, I think the first thing to address is your concern about the integrity of your flue. you're quite right, if in the past you had this situation where smoke was evident in your home from next door - this would suggest that the flues of your home and your neighbour's communicate in some way or other. this isn't what you need at all. I would say, and I can only go on the info you've given, but I think there's the possibility that an unsafe situation could exist with the installation as you've described it, whereby you could inadvertently be exposing your neighbour to risk through the use of you fire, and if your neighbour has any open flue appliance (or indeed some other type of heat producing appliance) connected to the adjacent flue on their side of the party wall, they could likewise be exposing you to an unsafe situation. A lot of the risk is going to depend upon the nature of any communication between the flues, their performance, and numerous other factors including weather/climatic conditions as well as the/any appliances involved. I would say that your key priority at the moment is to get this situation investigated, and then either resolved or made safe. In short, it sounds very much as though you really need a diligent RGI to attend and have a good look at exactly what is going on there.

In terms of the suitability of your flue, well, I'm afraid that's going to depend upon the nature of any problems found with your existing flue. Given that you've got an old baxi in there, the chances are you have a 5 inch metallic liner passing up through the chimney, so one would like to think this bodes well for the chimney's suitability on size grounds. Obviously though, it does seem like there's an issue with integrity. As a possible work-around, and it would depend very much on the state of your chimney, it may be feasible, depending upon what the appliance manufacturer states as to the suitability of different flue systems, to install a flue gas collector box along with a new flue liner to provide a solution. But first things first, get it checked out by someone who knows what they're doing, and who can see what it is they're dealing with - none of us here on this website can do that via the internet. What area are you in - there may be a someone on here who's local to you.

 

[bennygas]

because there are so many factors that affect the testing of an open flue, it is quite possible that it could've been missed, you have to remember, any fault may not have been there since day one so to speak. with regards to liners, your current set up could probably be described as a liner with a lined chimney - you probably have a metallic liner inside of a chimney lined with socketed and rebated clay pipes, but this is all pure guesswork. depending on where the smoke was coming through, it could be down to a breach within the builders opening (the back of the fireplace if you like) - which is arguably the most likely cause, and quite probably the easiest part to repair (given the fact that one of the most significant factors in repairing a flue is access). Unless the NACE chap is also Gas Safe registered for work on boilers and fires, if he identifies an unsafe situation, he may not be qualified to make safe in the way required of an RGI. Your best bet is to get a RGI to attend, explain the situation to them fully, and let them get on and test it properly and make their own assessment.

 

[Nostrum]

Who ever you phone, tell them that you have a gas fire in situ and you have had problems with smoke from next door in the past. You require a flue flow test carried out on the chimney and not just the liner as you may have to remove the liner if the new fire doesn't have a suitable spigot on the back.

You might want to get hold of your neighbour also and ask if they will allow someone to go into their property to carry out a similar task.

It's unlikely the flues share the same chimney as you would have to get 2 liners up the one (presuming that next doors property once had a back boiler originally also) and terminate them (not unheard of though) but the 2 may have been breached at some point or poorly built. It definitely needs seeing to though as it not right.

 

[bennygas]

good point, well made sambotc

 

[Nostrum]

I've just looked at the manual and it states you need a 5" liner to fit the fire.

Bit of a tough one to call as I suppose if you use a liner then you are protecting your appliance from effecting next door, but next door maybe effecting you. I'm not sure where you stand, presumably the party wall agreement law's would apply? It might be worth getting someone to check it and see if you can find out where the problem is.
If it's far up then you may have to break into the chimney somewhere to fix it which is going to be pretty disruptive. A balloon type liner will costs ££££'s so not really an option for a gas fire..

I'd also recommend you replace the liner as generally the recommendation is that they last the life of the appliance connected to them.

You might be better contacting a chimney specialist on this one, just make sure as said before, they are gas safe.

 

[Bernie2]

Hmm!

If the flue is clay pipe lined so should next door be surely?

So how come, the smoke is coming into your house from next door if both structures are identical?

It would have to go through their liner, then the liner insulation or flue material infill if fitted, then the party wall, then your liner or at least into your flue if the rest of the flue around your liner is not insulated or solid, Then through the liners bottom opening closure lintel.

It all sounds a bit fuzzy. I would seal your pot, and then seal the bottom opening and give it all a good smoke test, perhaps a few smoke pellets all at once. At least you may then get some idea of the extent of the problem.

Next door will soon run in to tell you if your leaking into theirs. That at least helps prove there is a leak between houses. Then hire a camera and have look down the flue. I have had places in which the wood beauticians (joiners) have carried joist ends right into flues causing leaks.

 

[spantik]

Well what a discussion. Thanks to everyone - I've certainly got something to go on but I'd be the first one to be delighted if I'd got it all wrong and everything is declared fine!!! Just need to be sure ay?

I can't help but think that the problem is next door and not with me although I accept that owing to poss negligence next door I may have something damaged too by now. The reason I say this is because I have had this house since it was built. I know every brick and every fault (well nearly!) i have nurtured it from birth!

Next door has had at least 6 owners since it was built and a multitude of bodged alterations including the removal of the back boiler years ago. There is no gas to their fire area now. The present owners are the first family to actually try to rectify things.
Apparently when I experienced a smoky smell from next door they had lit something like an 'alcohol heater' (not sure what my neighbour meant and I've probably got the name wrong but you may understand) and not a wood fire.

You are right in stating that the two houses SHOULD have the same flue/chimney type but I wouldn't bank on it after next door's history. Anything could have been done by anyone and definitely not legally.

They are happy for me/ an engineer to go round and observe/ test in their house so that's good. They are never happy to put things right though if it turns out to be their problem!!!!

WHAT GAS SAFE QUALIFICATION DOES THE ENGINEER NEED TO HAVE IN ORDER TO TEST MY FLUE EFFICIENTLY & LEGALLY - I KNOW THERE ARE DIFFERENT PARTS TO YOUR EXAMS AND YOU DON'T HAVE TO OPT FOR ALL OF THEM?

Anyone out there live near enough to me in the Midlands - CV10 0SG (N of Coventry just off the A5 on border of N Warwicks and Leics)?

 

[bennygas]

alright bernie, spantik

what with both flues probably being lined with something like say, clay pipes, and that they're both hopefully constructed as separate entities (which I think is a fair enough assumption at this stage, as otherwise, it could have been a complete nightmare to get the original metallic liners down for the old baxis); I completely agree that it's unlikely/less probable that any breach in the flue system is within the piped/lined section.

Given that the smoke seems to have been sensed lower in the flue system (and it would have a natural tendency to rise (unless cool and dense)), I'm thinking that maybe the breach is more probably within the unlined builders opening/gather section of the flue/s, especially as this is the part of the flue that was probably messed about with most when any alterations were made next door.
With regards to that smoke test, further guidance can be found in Appendix E of ADJ2 (I think the Smoke Test 1 paragraphs E13-E14, and also E9-E10 for sizing using coring balls are perhaps appropriate). here's a link to the doc:

http://www.planningportal.gov.uk/uploads/br/AD_J_wm.pdf.

the engineer you need would need to be gas safe registered for work on boilers and fires, like i mentioned earlier.

hope this helps spantik.

 

[spantik]

Great help. Thanks a lot.

Not that I'm in any way qualified to comment - BUT I think you might be right as this is where the aperture will have been altered. Thanks for help with the quals. too. The guy that's surveying on Thursday has both those quals.

I'll let you know!

 

[bennygas]

Hope it all goes well.

 

[Nostrum]

You say you smelt a smokey smell, rather than clouds of smoke? I wonder if it could have been downdraught, especially if you weren't using the fire at the time. Doesn't take much to get a sniff of it?

Could you take a photo of the arrangement? seems unusual that a late 70's house would even have a brick built chimney.. at least down here they were mostly pre-cast at that age if they had one at all!

 

[AWheating]

could have been reverse flueing when you smelt smoke( something like an extractor fan pulling air down your flue for example) could have been due to faulty builders opening. I have removed fires in the past to see the back of next doors gas fire. I even found an entire street like it, so these things did get done years ago. All i can suggest is get a qualified engineers in to check it out. Once you get your back boiler and liner removed you should be able to perform proper tests on the flue system.

A proper certified chimney sweep is your best bet for proper testing of a brick chimney, but may not be gas qualified and able to remove your boiler.

 

[spantik]

I think I'll have to get up on the roof again to remind myself what pops up up there! I know I've had the brickwork repointed up there so there's definitely some kind of chimney. Remember its a completely flat roof and you can't see the flue from the ground unless you walk 200m up the road and then it's a very poor incomplete view. I don't mind getting on the roof (if I can manage to get help to put the ladder up (I AM a 62 yr old female) but don't like getting off again but certainly not impossible!!!

Your comments are interesting AWheating but this is a recent problem for me - I think, as a result of bodged DIY work next door. My neighbours have no fire now - just a small aperture where the fire used to be and a hole upwards which must be their flue?! There's also no chimney breast next door (did I say that before?) but maybe there used to be? We think there's evidence of something having been there by marks on their ceiling.

Re the smoke I smelt. It was a smell ONLY, no smoke, when they were burning this alcohol-type heater (whatever that is).

 

[bennygas]

When the engineer who attends needs to see the termination of the flue, he'll access it - he'll most likely have what he needs, together with the confidence and experience to gain access in a safe fashion. To be honest, unless you've got smoke pellets in the flue at the time and knowledge of flue terminations, the information you'll be able to glean from climbing up there is likely to be limited/inconclusive, so please don't put yourself at risk unnecessarily.

 

[Nostrum]

Bi-ethanol fires are flueless as far as I am aware (never dealt with them at all) Which tally's up with the no chimney breast as well, and also the possibility that the builders have knocked it about causing problems.

Would be interested to hear what the result was when you find out, keep us posted!

 

[spantik]

ALL very helpful. Thanks a lot. I'll let you know! Let's hope I'm making a song and dance over nothing!