Damp in recently decorated wall (chimneybreast?)

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Please find attached a photo of my daughter's bedroom. This is an outside wall with a disused chimney on the other side. The wall had shown signs of damp for some time.

A few months ago we had the wall re-skimmed and then painted it. The damp issue re-appeared though and we asked a roofer to check the chimney and flashing etc. He made some repairs to the area which he thought was leaking.

The area doesn't seem to have got worse but the roofer is quite sure the chimney area and roof are water tight. Is it possible this damp is somehow trapped as it doesn't seem to be getting worse but hasn't dried out after 6 weeks? The chimney does have an air brick in it.

Thank you for any advice as I can't see where to go with it next.
 

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laodan, good evening.

Is the disused Chimney contained "Within" the wall or? is the Chimney a protrusion extending beyond the face of the wall?

You mention the Chimney has an Air Brick installed, i assume it is in the area of the old Fire place?
1/. Is there a Vented cap on the External Chimney pot?
2/. A simple test?? if you hold a small piece of tissue paper to the internal air brick, is there an "Air Flow? in that does the tissue flutter away from the Air Vent or does the tissue appear to be attracted towards the Air Brick?

Reason for this test [should you wish to employ it?] is that.
A/. It is OK to have an Air Vent but that vent is worthless if there is no vent at the Chimney head.
B/. If there is a vent top and bottom, but there is no air movement of the tissue, even on a windy day, this can indicate that debris falling down the internal area of the flue can easily block off the lower air vent [ a check if there is no air movement of the tissue is to use a very thin skewer or similar and poke it through the lower air brick holes it should be clear, any obstruction can indicate a debris build up issue?]

Why all the interest in air flow in a disused flue?

If the flue is un-vented then condensation will occur within the flue [Google Interstitial Condensation?]

Ken.
 
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Thank you very much for your reply KenGMac. I have attached a further photo taken from the outside. As you can see, the only air brick is actually where the fireplace downstairs used to be. There is no corresponding air-brick upstairs. Is this our problem? I did try the tissue test and no movement at all. Thank you for any suggestions.
 

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laodan, good morning.

A single air brick may be the issue?

Is there a Chimney pot? if so is it sealed or is it covered and vented?

Have you attempted to insert a thin piece of wood or metal wire into the lower air brick?

Ken
 
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Thank you once more KenGMac. We paid for the air brick to be installed last year and as far as I can tell it is double bricked (with air bricks).

I have also attached a photo of the chimney cowl. As far as I can see, we should have circulation at the top and the bottom?

Does it need an air brick higher up in the flue to alleviate the damp?
 

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laodan, hi again.

OK I am going to get pedantic.

That Chimney head appears large enough to contain two Flues? but only one Chimney pot???

1/. Is there another old fire place on the ground or Upper floor?
Why?
Because,

2/. If there are two Flues, there is a possibility that the lower air bricks have been inserted into a Flue that is still blocked up at the Chimney head level?

As I opened with "Pedantic" ?

The chimney pot in the Image posted should provide a more than adequate air flow in a Flue, it is odd that your tissue test proved negative?

Ken
 
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Please be as pedantic as you like - it is very considerate of you to help me in this manner KenGMac.

There were, presumably, two fire places - one upstairs, one downstairs, which have long been covered over.

So what we are saying is that, possibly, the flue for the upstairs fire place (and the one producing the damp) isn't getting any circulation?

I suppose the air brick may not have touched the flue at all if it's a casing within the brick shell?
 
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OP,
Your stack has a concrete flag capping it - the cap should be flaunched to shed water and securely fix the chimney pots and/or terminals. It should also be throated all the way round the overhang.
A pic of the flaunching and flashing would help?

You have a strange arrangement of a gas terminal with a vent terminal somehow fitted on top of the gas terminal.
Assuming that both flues are in this stack then I cant see if you have a second flue pot or terminal.

Given that you dont have a gas fire then only an air vent terminal (the mushroom one) is needed.
Plus, it might be a case of a SS flex flue liner has been abandoned in the flue, and is still attached to the gas terminal.

Unfortunately, you probably need to open both fire places up - on the inside or the outside - & have the flues swept.
Then install 9" x 6" plastic vents - on the inside or the outside.
 
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laodan, good evening.

Short answer to your last post is Correct.

So far the "Tissue Test" was not a success, no apparent air flow.

If I were you I would use a piece of wire, or a very thin Bamboo from the garden to see if indeed the air bricks penetrate into the flue or at least into the area of the hearth.

Until you can categorically prove the Lower air bricks are functioning, everything else is conjecture?

Next, the upper floor?

We now enter the land of IFF?

1/. If the lower air bricks are vertically below the chimney pot, then that would suggest that the air bricks and the pot are in a direct [vertical] line??

2/. If there is a Bedroom blocked of fire place, sited to the left [as seen when standing externally and looking at the Air bricks] then that would indicate that where the Bedroom flue enters the vertical external protrusion, will by necessity mean that the lower flue would be required to be Off Set to the right, this in turn would result in 1/. above being completely False, and because there appears to be no Chimney pot which will in turn be the cause of the problem.

As an aside if there is a problem as indicated in 2/. above, the insertion of a further air brick at high level into the flue will probably prove of use?

Ken.
 
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OP,
You have a strange arrangement of a gas terminal with a vent terminal somehow fitted on top of the gas terminal.
.

Where in the pictures is there a gas terminal?
i see a louvered chimney pot with a vented terminal fitted.
 

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