Removing stone(s) from a chimney stack?

[Kaymo]

Hi,
Long story so I will try to keep it as short as I can. I have a blocked chimney to an open fire. Its been blocked since in moved in 3 years ago and despite spending 1/2 a day at it before giving up and then paying a chimney sweep it remains blocked. The sweep reckoned that the block was near the top where the chimneys meet and that a good roofer could probably remove a stone or two from the stack to remove the blockage. The problem is that I am having trouble finding a good roofer that would do this sort of work, and the few recommendations that I had did not call me back - so I presume they are too busy or don't want this type of work.

So, my thoughts have turned to whether I can do this myself and wondered if anyone on here had done this before or had any thoughts on this. I was thinking of doing it from the loft rather than the roof to avoid the additional safety risks and possibly prising a single stone to one side then inserting a hydraulic jack or something before removing it completely. I think that if I could get one stone out then I could at least see what is going on, I suspect it is rubble that is lodged in the bend.

Any thoughts gratefully received .

 

[dann09]

Do you mean that the brick flues can be seen gathering in ( coming together ) in your loft?

The bend is a typical place for rubble to collect.

The chimney sweep should have given you a measurement to the blockage - sweeps count their rod sections as they go up a flue.

You could always measure down from the stack on the roof. If the blockage is at the stack, merely peer down with a torch, and then its simple to open it up.

Anyhow, by removing a few bricks from the flue bend you will probably reveal the blockage.

Finally, the whole flue should be swept and smoke tested.

No jacks or similar are necessary, perhaps, when you locate the blockage, come back here and we can walk you thro what to do next.

 

[Kaymo]

Thanks dann09, he did give me it in rod lengths and roughly estimated the distance from the top. This was what made me think its probably roughly where the chimney passes through the loft but as you say I would probably get a more accurate idea by sweeping down from the top.

Any advice on safety while working on the roof? I can get up easily enough as the bathroom window takes me out on to a flat section of the roof which in turn leads me up a corner. Once on the apex its fairly easy to straddle the roof and shimmy along to the chimney but I would have to stand up on the apex to peer down the stack and at this point I would like to be secured! I have a harness already, is it normally enough to tie a suitable rope around the chimney stack?

I would normally arrange a buddy to be present before I go on the roof or confined spaces so it might be a week or so before I can get started.

 

[Jackrae]

could simply be a massive heap of birds nests. If you get a chance it's worth having a look down from the top. Tie a torch to a rope and lower it down to illuminate the stack.

Not really recommended but i managed to clear a massive nest build-up in a lined chimney by dropping down a flaming rag down - once the nest took hold and it got air from below it went off like a jet engine.

 

[Kaymo]

I liked that one, sounds like something I would consider and it is logical, but I am just imaging trying to explain it to the fire brigade if it all went horribly wrong!

Seriously though, I am fairly sure that its not just crows nests but I think that is contributing to the problem. I cleared the chimney on the other side of the house myself and took about 4 barrow loads of birds nest crap from it. With this one it felt more like rubble. The sweep had some sort of special device for breaking up birds nests and it didnt work. In the end he came to the same conclusion that I had, that the stack had collapsed inside near the top.

 

[Alastairreid]

How many vents in the stack?

If the bridges have collapsed you may have to install a liner.

The bridges are the bricks which separate the individual flues within the stack.

 

[Jackrae]

Next thing then is a torch and a camera tied to the rods with a cable feed back down to a PC or TV unit. That way you can actually see the problem before you start destruction. Again, been there and done it. Lots of cheap cameras available on fleabay with 10 to 15 metres of usb cable attached; but you will need a separate light source (small LED torch) as the LEDs on the cheaper cameras are not much use at illuminating the width of a class 1 chimney.

 

[Kaymo]

alastairreid,
Not sure what you mean by 'vents' but I am presuming you mean number of fireplace/chimneys there are, and the answer is 4 on that side of the house. Its an old house and had chimneys in 3 other rooms on that side. All of the others are closed up and have a vent to the inside. I expect I probably will need a liner but just looking to see if I can get it open first, then I will need to decide if it will be a stove or leave the open fireplace.

Jackrae,
I like the idea of the camera, I had been thinking of this before but wasnt sure if I would realistically get a useful image - good to know that someone else has done this succesfully. I think I have and old webcam and a torch that I could hook up to the poles.

Regards,
Kenny.

 

[dann09]

Kaymo,

1. I dont understand; if the sweep gave you a distance to the blockage how come you haven't measured up the c/breast?

2. If you take a few bricks out in the loft - having ID'ed the correct flue - at the last bend where the flues gather, you will be able to clear the blockage at that point or in the stack above, without going on the roof.

3. Make sure that the fireplace opening is masked off.

4. If all the fire openings were blocked off when you moved in, then perhaps you should open them all, and have them swept and smoke tested. Maybe thats not practicable? But even redundant flues should be clean,sound and have a free air flow.

5. The feather(s) (or bridge) might be damaged, as above, but typically when you relieve the blockage all will be revealed.

 

[Kaymo]

dann09,
1. I do have a rough idea of where the blockage is just not exactly. The flue in question goes up in an arc and the line that it takes is not visible from inside or outside so I cant get a very exact location but I know from the amount of poles that went in that it is near the top.

2. Thats good, I will have to go on the roof at some point to put cowls or something on to stop the crows getting in but I wouldnt have been comfortable trying to remove those large sandstone blocks from the roof without some sort of platform.

4. I would like to open them all for exactly the reason you mentioned as I think they are all blocked but I am not sure how practical it is at the moment. If I can take the vent off and get the pole up then I might try that.

Having never done this before, I am presuming that I just need to chisel or drill out the cement from between the stone blocks and then lever it out?

 

[Jackrae]

I take it you appreciate just how heavy a sandstone block can be. Also, as they are of irregular shape, the mortar line you see at the face may bear no relationship to the actual mortar bed so removing a single block may be an extremely difficult task. So be prepared for lots of cursing and bruised knuckles.

 

[Kaymo]

Thanks Jackrae. I am very concious of the weight and size of these blocks. When I get to this point I will probably construct a platform at the level of the block I am removing so I can slide it on to it rather than risk dropping it through the ceiling!

I am going to try the camera first and then I'll come back to the forum if I have any questions prior to or after removing the block.

Thanks to all for your helpful comments.

 

[dann09]

Jackrae,
are you saying that your chimney breast is constructed with heavy sandstone blocks in its entirety? Often the loft bit is in cheaper brickwork.

If, as far as you can see, no building work has taken place on that roof area ( rubble thrown down the flue) the odds are that its an accumulation of nests - sometimes one or two feet thick, but nests. Persistent "poking" will eventually dislodge them.

A broken bridge/feather is a different matter.

So a camera down the flue would be your best bet.

 

[camerart]

Make sure it all goes back as nature intended.

When fitting a flue, it wouldn't go down, my builder took out a couple of bricks from the outside wall, 'helped' the flue, and bricked it up. When I was filling insulation between the flue and the chimney, it was going into the cavity, so he had only replaced the bricks that are seen but not the flue brick.

cheers, Camerart.

 

[Kaymo]

Hi all,
I bought a cheap webcam and attached it along with a light to the top of the first pole and pushed up the chimney. The image wasnt great, perhaps I need a better camera for this, but at about 8.5m up it showed something straddling the opening. Very hard to make out but if I was to guess it seemed more like something metal than stone or wood and I thought it might be a sweeps hook from a former attempt to clear the chimney. This is as far as I could get with the cable from the camera but is also a close match to the height that the sweep recorded the blockage at.

My next move was into the loft as 8.5m takes me just into the bottom of the loft. The pic below shows the triangular area where the 4 flues but apart from knowing that the one I am looking for is the furthest to the left there doesn't seem to be any other clues as to where it is so I might have to make a best guess as to where to remove a stone. I think I will get my wife to move the pole up and down to see if I can hear it or feel the vibrations.

Another slightly disturbing thing that I discovered is that just below where the light is shining in the photo is where power company have brought the electricity cable into the house. Poking away at this hole and the twigs etc come through so this cable seems to be coming straight through the middle of one of the flues. Although this is not an active flue it still seems like fairly dangerous practice, has anyone heard of this being done before?


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