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Chimney problems

When I was working the that bad corner of my house, I also checked the very top of the wall. Because of that I went up to the attic, and took a brief look to see that the layer of thermal insulation is fine. As, on the attic floor there is a bed of dry wood chips -they sell those at the local saw mill, and it is good material for natural thermal insulation. I noticed that there is a small opening in between the chimney and the attic floor. I placed my hand over the opening, and felt a flow of warm air coming from the rooms. Oh well - all of the last winter I was wondering why it feels like my roomtemperature falls faster than it used to do... But all the time I felt that I don't have enough energy to inspect that, instead I just did a lot of work, kept on heating, and waiting for the summer to come so that I can rest and then start seriously renovating my house. And now I realized that all the time there had been this small opening - as a first aid a placed to pieces of fireproof wool on top of the opening. (Like, 30 seconds to climb to the attic, 1 minute to look and find the opening, another minute to quickly fix it, and then 30 seconds to come back; three minutes of work - surely I would have had that much time at some point during the last winter. But I always just felt that maybe the problem is something very big and I'm too tired, so I never went to take a look...)

Well, couple of days ago I went back to the attic, to see what needs to be done to properly seal the opening. As, the thing is that it is not wise to have those wooden chips next to the chimney. So, something like 20 cm around the chimney has been filled with sand which also works as thermal insulation and is non-flammable. But where the chimney and the ceiling / attic floor meet, it has to be build tight enough to hold the sand. Apparently there were couple of openings, two centimetres wide. So, the sand had been dripping down into the rooms, finally leaving a free route for the warm air from the rooms to escape up to the attic. I thought that for this winter I can just place more of that fireproof wool to cover the openings as tight as I can, and then fix it better the next summer when it is warm. I was doing that, when I noticed another problem - a problem far more severe and dangerous.

Bit simplified, the structure is so that smoke from the stove enters the chimney ands runs up to the top of the chimney - no problem with that. Then, in the smaller room there is a parallel piece of chimney, and in the attic that parallel chimney connects to the main chimney. I noticed that a crack had appeared in the seam of the connection. Potentially, that could mean hot air and occasional sparks escaping through the crack, and in the worst case igniting the bed of wooden chips. Which, unless detected and extinguished in matter of few minutes, will lead to the whole building burning down. A risk that I certainly don't want to take. Sigh. That day I didn't have enough time to do anything about it, so I just decided not to use the fireplace in the smaller room - until I get the crack properly sealed.

Today I again climbed to the attic, to properly inspect the crack. Tomorrow it is monday, so if I need some more materials, I can go visit the hardware store. First I checked that it is not just a superficial crack, but goes all the way to the actual channel inside the chimney. Near the connection there is a small round metal lid, which can be opened to get access into the channel - that is for the chimney sweepers, and for people like me who want to check the condition of the internal structure of the chimney. Inside the connection I could feel the warm air coming from the embers in the kitchen stove. The main chimney has two channels, and the stove is connected to the another one - I was always bit unsure about the exact details of the structure is, but now I could verify that the parallel chimney from the smaller room is connected to the same channel as the stove. (What about the second channel in the main chimney - I still don't know for sure. It is either an old channel for an oven which used to be there, or then it is just purely a ventilation channel.)

Thinking about it I felt that I'd better do something about it, instantly. Like, there are many other lesser problems which I can just tolerate, waiting for better time to properly fix the problems. But a risk of burning the whole house is not such a thing - fixing such a problem can't be postponed. It came to my mind that I have a left-over piece of a softer version of that fire-proof wool. I tore thin layers of that, and used a knife blade to stuck the wool into the crack. OK, not a proper fix, but at least the crack was now filled with something. Also, I placed a fire alarm in the attic, near the chimney. And placed a fire extinguisher near the entrance to the attic. (Those fire alarms, they are designed for indoor use, but I hope that little devide will work in the attic where it is about the same temperature than outdoors).

With these immediate fixes done I sat on the sofa, thinking. In Finland a typical fire-place is so built that the hot air runs in channels inside the fireplace, heating up the mass of the fireplace. Which means than when the air has already lost some heat when it finally enters the chimney. That takes a lot of strain away from the chimney, as the temperature of the chimney walls won't change that much. But now the situation is different, as the only fireplace in the main room is that stove. The internal structure of the stove is bit simpler, which means that smoke and air entering the chimney is hotter. And there have been days when I didn't heat up the fireplace in the smaller room, but instead had a small fire going on in the stove for most of the day. I guess that might have caused the main part of chimney warming up, while the parallel chimney was still as cold as the outdoor air. Which, then, means that thermal extension causes the main chimney to shift a little - but just enough to open a crack, when the parallel chimney is cold and not expanding together with the main chimney. Well, that might be the explanation - but it also reveals that the connection is poorly designed - or then added later on. As, if such a conncetion is planned, then it is easy to build the chimney so that the connection is secured with two layers of bricks so placed that the seam of the stones in one layer is never aligned with the seams in the other layer. But I suppose that the main part of the chimney was already there, and later on somebody has added the parallel chimney, removing couple of stones from the main chimney to get an entrance into the channel, and then connecting the parallel chimney to that opening, sealing the connection with a layer of cement. Now, a superficial crack would be only that cement cracking, but this was not the case. It was both the cement and the seam of the stones which had cracked open.

In the autumn the chimney sweepers said that there is a potential problem in that connection. But it was another issue. As, there is an inner wall in between the main channel and the parallel channel. And the topmost stone in that inner wall seemed to be somewhat loose. Which means that if the stone breaks or falls down, it will fall into either of the channels, blocking the whole channel. If such a thing happens it naturally means that either of the fireplaces would become useless, as the smoke couldn't find a way out. In such a case the only solution would be to break the wall of either channel, remove the fallen stone, and then rebuilding the wall. Which, if done in the winter, would mean three or four weeks period when it is not possible to use the chimney - that's because the cement needs time to settle down until it can take the thermal expansion anyway caused by warm smoke running in the channels.

So, to clarify; First I need to decide what kind of temporary solution will make me through this winter (both keeping me warm, but not burning down the house). And then I need to decide if I want to properly fix the chimney structure as it is, or if I should somehow re-arrange it to make it safer. Several options came to my mind;

For this winter - I could be very careful, using both the stove and the fireplace in the smaller room, visiting the attic regularly (like twice a week) to check that the crack is still sealed by the wool. Or, I could just use electric radiators to provide basic warmth, and then only use the stove for short periods when cooking. Or, on top of the wool I could add an extra layer of cement, hoping that it makes my temporary fix more sound and safe. At the moment of writing this, the outdoor temperature is -15°C, indoors it is about + 14°C, and I have an infared heater placed next to my feet. As, I decided that at first the most safe option is to minimize using the fireplaces. As the days go by I can see what kind of room temperature I can maintain with electric radiators, and I know that more ideas will come to my mind when I just allow myself some time to process the situation.

But what about the years to come? First, let's take a look of the whole process: Before I bought the house the owners said that the chimney is propably broken and unusable. I was thinking what to do if that turns out to be the case. The modern way to fix such things is to install a smaller metal tube inside the chimney. In between the metal tube and the walls of the chimney all the space is then filled with fire-proof insulation material. That way it won't be a problem if there are cracks in the walls of the chimney, as the smoke and sparks will be safely inside the metal tube. It is simple to do, if inside the chimney every channel is separate, running all the way from the floor level up to the top of the chimney. But in my house there is this parallel chimney connected to main chimney. But how to install an inner tube into such a connection? I was afraid it won't be doable.

After I bought the house, I asked the chimney sweepers to check if the chimney has any cracks, is it safe to use, or does it need to be fixed in a way or another. And they said that it is OK. I was happy abot that. Well, there were electric radiators placed in every room, including the entrance hall. There was no fireplace nor a chimney in the smaller room. At first I removed all the electric radiators (knowing that I have smaller portable ones I can use if needed). And for the first winter I just closed the door to the smaller room, mostly just living in the main room. Later on I rebuilt the parallel chimney inside the smaller room, safely connecting it with the old part in the attic. (I mean, the connection part was all the time there, up in the attic. I only had to rebuild the part which is inside the smaller room. So, to be precise, the parallel chimney has two critical seams; first the one where the new part connects with the old part. And then where the old part connects with the main chimney. And now the problem is that old connection.)

Well, that's the story so far. But what next? If the connection is badly designed, then it won't be very wise just to fix it. Another possibility would be to remove the entire connection, and doing more of the masonry, continuing the parallel chimney upper and upper, opening a new hole in the roof, finally making the parallel chimney a separate channel all the way from the room to the top of the chimney. Another option would be to remove the entire parallel chimney, thus getting rid of the connection. That would mean no more fireplace in the smaller room. But instead I could have some sort of central heating system. Like, a wood burning stove which is connected to a water boiler, and then installing radiators and a pipeline circulating the hot water. Modern variations of this kind of system is commonly used in the Finnish countryside. (If you are interested in the details, one version would be not to have radiators installed on walls, but just a pipeline of hot water under the floor. That way the floor would be always warm, and as the warm air rises up, the whole room would be comfortably warm.) Or, then I could try to thoroughly examine the exact structure of the main chinmey, trying to figure out if it is possible to turn that secondary channel to be used only for the fireplace in the smaller room. (If that is possible, it would propably mean opening up a new hole in the chimney, near the floor of the second room. And then connecting the fireplace to that opening, likely with some more masonry to secure the connection.)

Well, but at the moment I don't have to make final decisions. Again, I'm in a situation where I can keep myself warm with temporary solutions - and I'm happy to notice that after all the therapy my old problems have turned into valuable experience. Like, surviving all the life-threatening situations in my childhood left me with bad memories and got me stuck in a partial freeze reaction; but those memories are just memories, there is no more pain nor anxiety associated with them. Some of the freeze state is still left, but all in all, nowadays I don't panic with this kind of problems. Surely, the risk of burning down the whole house is a serious one - and in a way I'm facing a huge problem, knowing that if I fail to solve it, my house might become unusable. But with everything I have learned, I can just take the situation easily, with a peace of mind. Allowing myself all the time needed to figure out the solutions needed. I mean, I several years ago this kind of sitation would have activated the old memories, making it hard to think clearly because of strong anxious fear of looming catastroph and destruction. But that reaction is gone, now there is just "oh, nothing to worry about, let's just take a look what we can do about this."

Hmm... some sort of central heating would be actually comfortable and nice. But the downside is that it requires an electric pump constantly circulating the water. And I'd like to be as independent as possible, being able to heat my house even if the whole electric grid collapses. Maybe I could have solar panels and wind turbines to locally generate electricity? Then, on the other hand, I don't know if I'd like the idea of heating beind dependent on high-tech I can't repair myself if needed. Anyway, I have to think about these and make some plans for the future.

PS. I added some pictures, hoping that they make it easier to understand the structures I tried to describe. In the first picture the yellowis stuff is that fireproof wool stuffed into the crack. In third picture there is a red dot indicating the problematic stone mentioned by the chimney sweepers. Also, the inner structure of the fireplaces is just a symbolical presentation. In reality the channels inside a stove and a fireplace are arranged differently, so that it is not possible to accurately draw in a 2D picture. But I guess you get the idea =)

left: main chimney. right: connection of the parallel chimney
left: main chimney. right: connection of the parallel chimney
the fireplaces of my house
the fireplaces of my house
a diagram of the structure of the chimney
a diagram of the structure of the chimney
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Comments

Phew! Those old chimneys are a lot of work to fix.

My house, an old farm house built in the early 1800s, it had similar leaky old chimney problems years ago when my cousin was living in it. She ended up just building a whole new chimney on the outside of the house, offset from the house by about 60cm, but held onto the house by long steel brackets. Being completely outside and away from the house like that, it does not heat the house as efficiently as an inside chimney would, and it fills with creosote and requires cleaning more often. But at least if there is a flue fire there is not as much danger of it spreading to the rest of the house, I guess.

I still hope to fix my old inside-chimney someday, but I think I will have to completely tear it down and build a whole new one. And there are so many other more pressing things that need to be fixed! I think I may just buy one of those outdoor wood furnaces that circulates hot water into an indoor heat exchanger instead, and just keep the wood stove in the kitchen for when the power is out.

Yup, living in an old house is always a question of setting priorities, as it is never possible to get everything done at once. So, more pressing matters are to be taken first, and others are postponed until later.

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