Source of black on ceiling

BanjoSpanner

My house is about 25 years old, I've lived here for 17 of them. About two years ago, a tiny black dot appeared on my bedroom ceiling. Now, there is a two foot deep band of blackness stretching from wall to wall across the front of the window. It is beginning to smell slightly I think.

I went up in the atic and I found that the space above the blackness has no insulation. There is a reason for that as it turns out, which is that the area

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is completely inaccessible up there to be able to get at it with insulation. I've attached a photo and as you can see, there is an arrangement of timbers there spanning the full width of the room, and it would be impossible to get in there with insulation. The original builders must have thought the same when they were insulating so they left it bare.

Could that be the reason for the blackness now? And if it is, why did it seem to be ok for the first 23 or so years before it started to appear?

I'd appreciate any help, views and opinions. I'm thinking I'll probably have to get a professional in to deal with this, but I'm not entirely sure what kind of professional I need.

Deregos.

https://www.boards.ie/discussion/2058389669/source-of-black-on-ceiling

Spray that mould in your bedroom with bleach. Could you scoop bags of polystyrene insulation into the gap?

phormium

Isn't bleach supposed to be the worst thing for it as it doesn't kill it at all? I see vinegar recommended these days. Anyway do something with it, that's a lot of mould to have in the room, why did you not do something before it stretched from wall to wall in a 2ft band if I'm reading that right!

Anyway why has it happened now, my opinion is the past two years I think have been the wettest for a long time, certainly in my neck of the woods, I'm basing that on two things and nothing to do with weather reports etc. I have damp patches in a sun room that is there 25 yrs and the patches only started last winter, no obvious reason other than air is walls are wetter from constant rain. I have also been attempting to do a small roof repair on a shed but was trying to get the wet timber dried out first, at no stage since early last summer has there been enough consistent heat/dry spell to dry that timber!

Can you basically throw some insulation roll over the timber or even an old duvet, amazing how handy they can be!

Hobby farmer

Is there any plumbing running above it?

policarp

https://www.boards.ie/discussion/comment/123069974#Comment_123069974

i would think ventilation is your problem.

if you can't leave windows open, try using a de- humidifier

And see how it works.

Hobby farmer

I would agree but it's in a very specific area and grew out from there so a leak is a possibility

Cerco

Is water getting in from your gutters? Can you put a phone camera down in the gap and take a few photos using a selfie stick?

BanjoSpanner

Thanks everyone for your time and replies. I went back up in the atic, no pipework at all up there and I see no evidence of any water from guttering.

I have now copped that the pattern of staining on the ceiling exactly matches the areas of missing insulation in the atic. I have also noted that the window right beside the area is almost constantly wet with condensation on the inside. So I think the most likely case is condensation on the cold spots where there's no insulation.

So I'm going to find some sort of cellulose fibre material that I can pack into the tight spot in the atic, and then fix up the ceiling below. Hopefully that'll be the end of it.

Thanks again for all your replies, much appreciated.

Tefral

In conjunction with that you're doing you will have to also increase ventilation in the room. The wet window is a dead giveaway of high levels of moisture..