Removing chimney stack (external chimney)

[Charlie6]

Hello All,

After multiple attempts to fix a leaky unused external chimney it looks like the stack will need to be removed to roof tile height. I wanted to find out if there are any issues to consider before the work starts or if it will be fairly straightforward as the chimney is external? Will the remaining chimney need to be somehow ventilated at the top?

Many thanks for any help

 

[vinn]

Who made the multiple attempts to fix the leaks? Did they provide photos of what was attempted and why?
If you post photos of the chimney stack we could maybe help you discover a cheaper, easier way of fixing the problem without dropping the stack.

 

[Charlie6]

Thanks, Vinn. I had a new roof fitted last year and ever since have had problems with a leaky stack (damp appearing on the wall and ceiling of the bedroom adjoining the chimney breast). There is also a damp patch on the wood in the loft which is underneath the chimney back gutter. So far the roofers have been back 6 times to try and fix the problem. They have raked the joints where the lead cuts into the chimney bricks, popped some lead sealant on top of the lead and put a bellcast around three sides of the stack.

I hope that the latest fix will resolve the issue but in case it doesn't I want to find out about removing the stack.

I'm concerned about how the chimney will be vented if the stack is removed. Does it have to be vented externally and if so how?

Will try to get some photos loaded tomorrow.

Thanks very much

 

[vinn]

Until i see a photo of the chimney breast and stack i dont know how to advise you.
I'm thinking is this an external chimney breast on a gable wall? If it is then dropping the stack and patching the roof is straightforward. Air bricks can be let into the face of the chimney breast near the peak. One vent per flue and at any fire openings below to give through ventilation.

The roofers appear responsive but not very competent. Returning that many times will rip the profit out of a job, not to mention the aggravation.
The roof could be leaking up above the back gutter but presenting at the back gutter.
Sometimes when re-roofing, if the old lead is left in position, the new roof cover: tiles replacing slate etc. wont work with the old back gutter..

 

[Charlie6]

I have quite a lot of photos from various stages but will try to upload a photo from inside the loft showing water on the wood, one of the damp patch on the bedroom external wall (the chimney breast is on the other side of the wall) and some of the stack before the bellcast was fitted to the sides of the stack. I also have quite a few close ups of the back gutter but am not sure if they are needed.

Does this help?

 

[Charlie6]

I have a photo of the stack from the other side but the file is too large to upload so I might have to see what I can do to reduce the size

 

[Charlie6]

Hopefully this will work

 

[vinn]

The flashing details around the stack have been done by someone who doesn't understand how to do it properly.
Profiled concrete tiles must be flashed in a particular way.
As it is, the flashed area isn't and cannot be watertight.
You will have to lift out all the flashing and let a competent leadworker do a proper job. Dont mess with it strip it all out.
No more bellcasts.
You will also have to probably lift and re-arrange some of the surrounding Marley roman tiles, and maybe replace with a few new tiles.

I dont see any roofing felt in the photos?
The gutter is not to falls and its holding water.
The next stack along the roof seems to have a similar flashing arrangement?

 

[Charlie6]

Thanks again, Vinn. The owner of the roofing company has had a look at the stack and cannot understand why there is a leak. He has offered so solution if the latest attempted fix doesn't work and said we have the "Rolls Royce" standard of stack work.

He seems unlikely to want to spend any more time and money on this and if this is the best work they can do I'm not sure I want them back again.

Can you offer any suggestions as to how I can locate a competent leadworker as I have no recommendations to contact? The roofing firm I used were recommended by a neighbour and that was my only recommendation.

There is roofing membrane (roofshield) and yes the front stack has the same leadwork but is not leaking.

 

[vinn]

No roofing felt can be seen in the photos?

The sheet lead org. or the IOP might be able to help you find a competent leadworker but any proper plumber or roofer knows how to work stack flashings.

 

[Charlie6]

I'll just get the stack removed as this will prevent any further poor leadwork

 

[vinn]

If you want advice on how to have the stack dropped come back here.

 

[Charlie6]

I would love any advice you have to offer about having the stack lowered!

 

[vinn]

There must be a min. of two workers.
Seal off all the fireplaces and flue vents.
Have the flues swept: you dont want any accidentally falling rubble to carry down clouds of soot with them.

Erect a tower according to instructions that will come with the tower delivery. When you reach gutter height remove a length of gutter to allow the tower to tie-in tight to the chimney breast.
Tie in the tower (a must). Use stabilisers if its doable?
The tower platform must raised to give an easy working height for the top of the stack.
When you next drop the platform it must give easy working height at the eaves level.
Using a pole ladder is safer than climbing on the tower.
Its also safer to lower buckets of rubble to the base of the tower.

Use a lump hammer and a cold chisel and remove the flaunching, pots and terminals. Pull out any SS flue liner(s).
Stuff something down the flue(s) to catch rubble.
Gently remove one brick at a time - knock the brick and then prise it out. One at a time.
Work down to below the rafter level to approx wall plate level.

Now, if your eaves is similar to the neighbour's in the photo you will have to make site calls for how you will finish off the raw top of the chimney breast, given you have no fascia.
The chimney breast top should be sealed (mortar in some flat slates) to keep out birds. Air bricks can be let in to each flue near the top of the chimney breast.
The roof will be patched in a conventional manner.
Its assumed your existing gutter runs through.

 

[Charlie6]

Brilliant response, Vinn! Much appreciated.

As I'm rubbish with heights I will contact some local roofers to get some quotes but will ensure they remove the liner, explain how they will seal the top of the chimney breast and will pop in a couple of air bricks. Can I just check that the chimney top cannot just be vented into the loft space as we have great high and low level ventilation in the loft?

I have noted the guttering run needs to sorted out.