You know its that time of year when all the damp threads start to appear!

We’ve lived in our current house for the past 20 months and I’ve just noticed a large section of the upstairs chimney breast that is soaking wet.

It’s a typical bay fronted, hall entrance Victorian terrace. There’s the usual central fire places for front and living rooms. At the back of the house there’s also a chimney breast but the previous owners extended the house and built a new kitchen. The old fireplace is somewhere behind there encased by new stud walls.

The chimney doesn’t extend out of the roof, it was taken off some time ago and it is capped in the loft space. There is an air brick at the top of the chimney on the external wall. Where this chimney breast extends through the upstairs bedroom it is soaking wet from the picture rail down about 3 feet. Above the picture rail isn’t as wet, it’s slightly damp, but not wet.

It also seems to have happened in the last few days, possibly 1-2 weeks ago as there’s no mould or anything, it’s just wet. A roofer has just come out and checked the roof and tiles for cracks but says its totally sound. Inside the loft space seems totally dry too. There are no water pipes anywhere here either.

Any idea what the hell could be happening?

condensation as the chimney breast is cooler than the rest of the room?

Poltergeist.

We’ve just had two big damp patches appear on an internal party wall in our kitchen that is wallpapered. The patches are a good 5 feet apart. One is top middle of the wall and the other is bottom left on top of the skirting board.

I’ve had the floor boards up in the bedroom above and it all looks dry up there.

I’m confused where they’ve just appeared from and can only put them down to condensation so far.

Good luck tracking the problem.

Is it part of the party wall? If so is the problem coming from next door?

Have you checked for blocked guttering? Just a thought, but it’s probably condensation, been pretty mild and wet recently.

Probably condensation. Cold chimney air, warm house. Any ventilation lower down? (oo err!)

Our place has recently suffered damp higher up around picture rail, so spent this morning up a ladder cleaning gutters and checking the chimney stack….

Defo that time of year…

Photos should hopefully help,so here we go. This is the room:

The back wall and chimney breast are on an external wall. See below. To my right is another external wall and window.

From Outside:

You can just make out some cracks in the render that show the chimney and the air brick at the top.

The wet patches extend from the picture rail down about 3-4ft to the level of the dresser. Almost all the way down the length of the mirror, about 5ft down from the rail, but just confinded to the width of the mirror!

What causes Condensation on just this wall and not the window say? Window and sill are totally dry.

Would opening up the window make it better or worse, letting in more moisture?

I had condensation on my cellar floor, I did not know if it was condensation at the time so I stuck down a peice of Alu foil, taped all round so that no air could get under. If it is a condensation problem you will see condensation on the Alu foil.

Not sure if this helps you or not, because I imagine it was a lot easier to stick some Alu foil to the floor rather than your internal walls, but maybe it gives you an idea for testing !

How about measuring the temperature of the wall with one of those laser temperature devices?

Sorry to ask the obvious…. Your not drying clothes in the house, in that room specifically? Showers have air vents / fans?

A dehumidifier Should keep it under control whilst you diagnose the problem

Driving rain getting in the air brick?

Ours is exactly the same atm – it’s where the chimney breast meets the roof.

Will be pointing, possibly bit of flashing – Easy/cheapish (sub £300 job).

Patriotpro – the chimney terminates in the loft space about 12″ before the tiles. It was taken off some time ago. I haven’t checked whether there are bricks in the top of it or its just a hole straight through to the kitchen downstairs though.

TooTall – Thats crossed my mind but the wet patch is at about the level of the braces and below. Also, we haven’t had driving rain that hard and at that acute angle to cause the amount of moisture inside. I imagine we’d be flooded inside with the amount of water coming in there!

Selled – Nope, we use the launderette 1 min a away down the street to dry our clothes.
We have a downstairs shower that vents elsewhere, unless there is a problem with it. However it is only used once a day for 5 min at most.

I’ll investigate the shower vent just in case and try a humidifier.

hope this helps: Odd damp patches suddenly appeared{solution}

Space station passed above you? 😉

I haven’t read all the above.

Assuming it’s a Victorian house and had coal fires, then soot and salts remain in the chimney brickwork. A dehumidifier is probably your cheapest option. That would be a lot of brickwork to dry out so don’t expect a quick result.

I believe I can see cracked render to your exterior – at what I assume is this spot (roughly)?

-> Water tracks/runs down wall area above. It reaches this point and enters wall. The running section of the crack is collecting and channelling water towards chimney breast – where it enters wall and accumulates- voila?

The spot: Look at the knob things on conservsatory then 1/2 inch left and up (as the photo shows it).

Seems odd to have a chimney breast on that back wall, and be able to see it through the render — but stranger things happen. Is the back room original?

We have a mystery patch where our chimney breast was taken out.
It never gets any worse.
We put our sleuthing hats on and have worked out that they patched the wall with the wrong kind of plaster.
Apparently some plasters absorb water and that’s what our patch is doing. We shall seal it next time we decorate.