Damp 'spots' on upstairs chimney breast - Please help!

[richardbell81]

13. Redundant flues require venting - top and bottom.

14. All your flues are redundant then?

They are yes. The front one is permanently redundant and I'm hoping to put a gas fire in the rear chimney one day when we can afford it, although that wont be any time soon. The rear one is where the current free standing electric fire is.

As I said, the rear one has definitely not been capped off at the top and as far as I know, neither has the front one but I will have to double check that.

 

[joe-90]

I suggest that you do what Danni says. Two grand's worth of messing around - but it still won't fix it. Then again, who cares? It's your money he's wasting.

 

[richardbell81]

I suggest that you do what Danni says. Two grand's worth of messing around - but it still won't fix it. Then again, who cares? It's your money he's wasting.

I've not decided to do anything yet, i'm just trying to get some opinions so I can work out how to tackle the problem. I've had various people come and look but not one definitive answer so I figured asking for some opinions on here was worth a shot!

I can only think that the damp on each stack, and on the back wall is caused by various problems, not just one. I can't think of a practical way to stop warm air getting up the rear stack as you suggested. And there can't be any warm air getting into the front stack as there is no opening.

 

[richardbell81]

Thanks for the pics,

1. I'd suggest that you have sulpherisation in the chimney breast flues - ie. chemical reactions of old soot and fresh moisture "eating" it's way thro the brickwork and plaster to the surface where it attracts moisture from the air. This is not condensation.

2. I'd also suggest, that you have minor leaks at the back gutters and slightly up the slating - slipping, replacement and split slates. This leaking is showing near to the purlins. Can you get a view in the "loft" space, look for leaks, stains and underslate felt.
Is the lower roof your neighbour's? There's some step flashings missing.

3. The flaunching appears to be loose and it's probably allowing moisture into the flues to feed the sulpherisation. Plus the pointing is failing.

4. Do you know how the chopped off c/breasts are supported?

5. Is the black stove pipe in pics 8 and 9 false?

6. Pic 4 requires a vent in the c/breast.

7. If "dirt" was falling down the flue it would indicate something wrong in the flue or at the stack/terminal.

8. Have the flues ever been swept or camera examined?
There should be 4 terminals in total on each stack?

9. Suggest that the roof at the stacks and flaunching and flashings be inspected from a roof ladder.
Perhaps you will have to open up the fireplace (s) and sweep the flues with "chains".

10. Knock off all plaster to the bedroom c/breasts and render in a lime and sand mix, with a board or remedial finish. No tanking req'd.

11. Perhaps discuss these issues with your neighbour?

12. i give this advice with the proviso that i'm not there - my information is limited, someone on site might say different.

Thanks for this Dann, I do appreciate all the points you've made. To answer your questions...

2. There is no felt beneath the slates and I can't access the roof space directly above the ceiling of the bedroom as the bedroom walls go right up to the roof (if that makes sense). There is just enough room to stuff some insulation between the top of the bedroom walls and beneath the slates so that the walls are insulated. The loft spaces either side show signs of black mould (another problem I need to sort) but neither has any obvious leaks. As I said, I did have the roof repaired about 8 months ago. Broken slates were replaced, flashing around the chimney repaired and the ridge tiles re-pointed.

The lower roof is next doors roof... however there has been no one living there since november.

4. The middle section of the chimney (in the bathroom) has been removed and there is a concrete support in the attic holding up the remainder of the stack above.

5. Yes this is false. I made it out of a soil pipe and collar, it just lifts off the top of the electric fire!

8. The house was rented before we moved in and it had an old wall mounted gas fire which I removed to expose the brickwork. The old gas flu liner is still there pushed up where it has been blocked off. The only test we did was a smoke test which it passed. We were getting quite a bit of old soot coming down which is why I blocked it off. I wasn't overly concerned as the house is over 100 years old so there are bound to be old soot deposits up there. I will get the terminals checked out properly. The lack of terminals suggest that some of the chimneys have been capped off. Would I still need a vent in the front bedroom (pic 4) if the chimney has been capped off?


Not sure if all that makes sense but thanks again for the help.

 

[joe-90]

If the stacks have been capped then you have to ask yourself why that is. There are around 50,000,000 uncapped stacks in the UK that don't cause any bother - so why are yours capped? Obviously they had the same problem that you have and some numpty came along and said it was rain getting down the chimney. It didn't cure it though did it?

Warm moist air has a positive pressure and will find a way to get out of the house - usually up the chimney. That's where it condenses and enters your bedroom. It's pretty basic stuff. Do a search for 'loft condensation' - the problem is identical.

 

[dann09]

Item 2. Research insulated pitched roof construction.
The difficulty is that there should be felt and an air gap between the felt and the insulation.

Where is the loft space mould that you refer to?

Surely, there's a trap in that flat ceiling? Same goes for the attic stud walls. You really should have a view of the under roof.

Pic 4. Yes, you must open it up, sweep and vent, top and bottom. The redundant liner will have to be removed. Research sweeping eg. on youtube.

If i understand you ,you will now only require one air terminal on your side of each stack.

The sweep will have to advise on how to sweep and clean the rear stack flue.

Pic 5. shows faulty slating.

 

[richardbell81]

Item 2. Research insulated pitched roof construction.
The difficulty is that there should be felt and an air gap between the felt and the insulation.

Where is the loft space mould that you refer to?

Surely, there's a trap in that flat ceiling? Same goes for the attic stud walls. You really should have a view of the under roof.

Pic 4. Yes, you must open it up, sweep and vent, top and bottom. The redundant liner will have to be removed. Research sweeping eg. on youtube.

If i understand you ,you will now only require one air terminal on your side of each stack.

The sweep will have to advise on how to sweep and clean the rear stack flue.

Pic 5. shows faulty slating.

I can access the loft space either side of the bedroom through traps, but there is no trap to access the flat roof above. This is something I plan to do. The mould occurs on the wooden joists in the loft space I can access. I am planning to have some air vents fitted to the roof this year to help the black mould problem.

Because of the age of the roof, there is no insulation/kingspan or felt directly below the slates in the roof joists. All the insulation runs along the 'floor/ceiling' joists. The insulation has been topped up to the recommended depth. I've attached a pic so you can see what I mean.

Untitled

• richardbell81
• 21 Feb 2013
• 1

 

[joe-90]

It's your money.

 

[richardbell81]

It's your money.

It is... But i've still not decided what exactly i'm going to do with it! Just weighing up everyone's helpful opinions!

 

[joe-90]

How many times will you refuse to accept the facts.

Your loft is going mouldy due to warm moist air from the house getting into it. There is ventilation between the slates so you must be pumping mega water vapour into your house. Another vent or two won't help.

That same water vapour is getting into your chimney and condensing in there too - and finding its way back into the house through the mortar joints of the chimney.

Only you know what you are doing wrong. Probably drying clothes on the radiator.

I give up from now. I've explained your problem but others are leading you astray.

If you think that it is water from the sky - then explain why 50 million chimney stacks don't have your problem despite being wide open.

 

[richardbell81]

How many times will you refuse to accept the facts.

Your loft is going mouldy due to warm moist air from the house getting into it. There is ventilation between the slates so you must be pumping mega water vapour into your house. Another vent or two won't help.

That same water vapour is getting into your chimney and condensing in there too - and finding its way back into the house through the mortar joints of the chimney.

Only you know what you are doing wrong. Probably drying clothes on the radiator.

I give up from now. I've explained your problem but others are leading you astray.

If you think that it is water from the sky - then explain why 50 million chimney stacks don't have your problem despite being wide open.

Hang on... I never said you were wrong and that anybody else was right, and as i previoisly said, i certainly havent made up my mind of what to do yet!

I just wanted a bit of help without the usual patronising attitude that a lot of 'professionals have! I do value any opinion given providing its in the right manner.

Thanks for the advice, which I do appreciate and will take on board.

 

[dann09]

1. Things become much clearer. You do indeed have condensation below the slates, but this has nothing to do with what is occurring on your c/breasts.

2. I take it that the flex ducting for the bathroom extractor is the flex in the pic? Is that daylight around the ext terminal flashing?

3. As advised above, no roof void air vents are necessary. For the time being, you want to seal the roof void off from any air escaping from below, make it drum tight.

4. Ignore the mouldy rafters and laths for now.

 

[joe-90]

It's just the same issue Dan. Why do you think that it isn't?

 

[Pernah]

I got exact same prob in my house and found out after several years the chimney was capped off, even for the one we had gas fire fitted by Corgi registered gas man!!

I had a chimney pot and cowl fitted for the flue connected to ground floor fireplace and made mistake of not doing the same for the bedroom one as damp reappeared, even though not as bad as it was before decorating.

Put a chimney pot and cowl for both flues and problem should be solved or better than what it is anyway as condensation trapped at top of flue making its way out through the walls - estimate cost:£35 per pot, £25 per cowl and £120 to fit with flaunching?