Neighbours smoke down chimney

lagi

I have a shared chimney with 2 exits each. Next door have had fitted a multifuel stove with liner a while back and for the first time today smoke has come down my chimney.

After a bit of research i have opened a window a little in the room and this has created the draft needed to create a good draw on my chimney.

This fireplace is currently open due to having a gas fire installed into it later this week. Once the gas fire is installed, would that be the end to the problem?

I am also planning to fit a multifuel stove with liner in my other stack, so do i need to do anything to the gas opening on the chimney as i was only going to fit a bird guard on that one?

rustyboy21

You may have a shared chimney stack with next door, but that does not mean you share the chimney flues with them as well.

Each room which has a fireplace or the potential for a fireplace to be fitted , will have it's own seperate flue, it will not be shared with any other room.

It sounds like the nextdoor neighbour has a leak in their liner, along with theirs and your original flues also being faulty, i.e the mortar has gone and is leaking fumes into an adjacant flue. This is a potential death trap which needs sorting.

You will have to have your flue lined for your gas fire, as well as lined for when you have your multifuel stove fitted. Your gas fire will more than likely be able to get away with a 125mm copex liner, which are the chaeper end of liners, but it will still cost a few 100 quid

The priority , however at the moment is to get your neighbour to get their liner fixed, they are pumping dangerous fumes into your house, most probably into theirs as well. Ths won't stop if you fit liners youself, they have to get their liner sorted out. You will still need liners even when they fix theirs, as the original flue is faulty.

You having a fire installed into this fireplace, will not stop the fumes from entering your property, the fire will not block these fumes from coming in. There is no way that the fumes will be coming perfectly out of their cowl on the stack and coming down your flue, it doesn't work like that, there is a fault which needs sorting.

lagi

It would be unlikely they have a leak in their liner as it was only just fitted and signed off a few weeks back. We do share the same stack and have 2 flues each. On looking stuff up it does say this can happen. The multifuel stove will be having liner fitted, but the gas fire will be using the chimney flue, the installer has already looked at this and is coming in the week to fit this. Its a class 1 fire.

This is one of a few things i read, all saying similar.

if the two flues are close together in the same chimney then yes you will get smoke down your chimney into your home, all fireplaces work fine it is the house that can be a problem to include negative pressure, natural (house stack effect, hot air rising and getting out through the roof, drop down attic doors or other areas) Mechanical (kitchen/bathroom exhaust fans, cloths dryers, boiler/furnace) all pull air out of the house. Do you feel cold air coming down your fireplace? If so try this if the chimney is clean open a door and window in this room with the fireplace in it and see if the fireplace draws you need to stop the air from going out of the house (mechanical and natural.

rustyboy21

lagi wrote: »

It would be unlikely they have a leak in their liner as it was only just fitted and signed off a few weeks back. We do share the same stack and have 2 flues each. On looking stuff up it does say this can happen. The multifuel stove will be having liner fitted, but the gas fire will be using the chimney flue, the installer has already looked at this and is coming in the week to fit this. Its a class 1 fire.

This is one of a few things i read, all saying similar.

Could you point me to where you have seen this? It is a bit confusing TBH.

The gist of what I get from it is that things like extractor fans,open windows etc will create a negative pressure in the house which will effect the draw of the flue. This is correct, that is also why you shouldn't use ceiling fans and cooling fans ( desk fans ) at the same time as operating a gas fire, it will effect the draw of the flue and craete spillage of fumes into the room.

Next door neighbours flue is lined , which will go up the existing flue and end with a cowl on the roof, if this is perfect, there will be no way of any smoke leeching through the original flues into an adjacant flue, then ending up in your room.

Putting a gas fire in the opening will not block up the opening. A class 1 gas fire has large exhaust ports at the rear of it, which will still let any of next doors fumes still enter your room. By opening the window in your room, all you are doing is creating additional air pressure in your room, to conquer the down draught of your flue, making it draw better. You shouldn't need to have the window open 24/7 in order to have a fire. There is something wrong with your and their flues and I still say the liner is faulty.

I would really stress the need to have a Gasafe and Hetas registered Chimney specialist have a look at the flue before you get the fire/stoves fitted. The smoke will not go away.

I have been selling fires and fireplaces for over 25 years and have not heard that by opening a window, that is a remedy to bad cross spillage of flues, it seems rather dangerous to me.

You are still not taking into account that the fumes can also leech through the plasterwork into the room too.

lagi

It is a gas safe engineer who will be fitting the gas fire, i will tell him whats been happening and he can do some further checks.

This was the first time this had happened yesterday, so will see what happens tonight if they light it. Maybe there was some unusual wind turbulence yesterday.

Gloomendoom

We have had this happen occasionally but only when the (huge) kitchen extractor fan is turned on. We don't use it at all when our fires are lit.

muckybutt

As a sweep I can tell you it is very unlikely the nextdoor neighbours liner is damaged.

Strange as it may sound is that atmospherics and wind direction have a lot to do with draught problems. I see it regularly when my custys phone to say they think the liner or chimney for that matter is blocked because they have smoke coming back down the chimney.

9/10 its due to atmospherics or user doing something wrong.

You say at the moment your fire place is out of action pending the fitting of a gas fire, depending how long its been since it was last in use you could also be suffering with what we call a cold chimney, cold chimney's wont draw air up them from your side but will and do draw air back down them, you will find that once the gas fir has been installed and you are getting the chimney warm again you shouldnt get back draughts.

Same goes for the stove install, now another point there is you dont have to have your chimney lined if it doesnt need lining, only way to find out is to do a pressureised smoke test, that involves warming the chimney up slightly then capping it off by placing a bag over the chimney pot, then smoke test it from below, the smoke will rise and try its best to escape, if there are signs of it escaping then yes you will need it lined, if no smoke escapes they no need to line and it saves you a good few £100 quid as well. Personally as a sweeps point of view liners are great, very easy to maintain and sweep and a lot cleaner, but as I say there is no legislation that says you have to have one.

Chimneys are complicated things believe me.

lagi

Update: Had the gas fire installed today and chimney has good draw, so probably a few factors. The room is empty and fireplace was completely open and would be cold as no heating has been on for a while.

Also it never happened again since posting.

Interesting stuff, hopefully the post might help someone else with similar symptoms.