Wet bedroom walls- Condensation?

Arsenal2019

Hi,
Where the ceiling meets the bedroom wall in my bedroom, it has recently become extremely wet. I have been sleeping with the windows open and the bedroom door wide open; yet it seems to be getting worse.  It only seems to be happening in this one room. 

The house is a 2 story mid terrace house and the bedroom is on the 2nd floor and this occurs on the exterior wall. 

I have been up in to the loft and the insulation is very thick and is all along the wooden timbers on the floor. The insulation spans the whole of the loft floor and goes right up to the where the slate roof joins the  stone wall (there is approx a 6’’ gap). When I pop my head up into the loft I immediately feel a draft and the slates look as though they are wet/moist.

I have lived in this address for 4 years and never has it been this bad. Yes I understand it may be a little damp due to the cold weather recently but I feel this is excessive.

Does anyone with any previous experience of this be able to share anything with me to help me fix/contain this? Could it be a problem with the guttering/roof/ damp?
i have attached a photo and hopefully you can view it **note- the top dark patch is the curtain pole shadow

Do I need a new roof, roof ventilation ? I’m stuck for ideas / solutions.  I’d just like to have a better idea before a roofer tries to rip me off!

HampshireH

Is your insulation sat above this area wet?

Arsenal2019

HampshireH said:

Is your insulation sat above this area wet?

No, the area which is wet is right on the joint of where the wall meets the ceiling. The insulation is pulled back from the exterior wall, roughly around 6’’.  I spoke to a roofer on the phone and he said that this was a good thing?

Jeepers_Creepers

The good news is that this is not condensation from inside your bedroom - you are doing absolutely the right thing having your windows on vent overnight, and the door open is probably good too - tho' you could probably shut the door if you want as this might actually be allowing fresh warm-moist air into your bedroom from the rest of the house. Your call on that - try both! See if cond forms on your glass.

The patch is FAR too wet and localised for condensation. That is almost certainly coming from above the ceiling. There are actual 'runs' from that patch = that's 'wet'.

Two obvious ways this could happen; one is your roof has failed somehow, so water is getting in past your tiles or any flashing between your house and the adjoining one - ie, there's an external 'leak'. The other is that the wet/moist you see on the underside of your roof slates is trickling down and landing at that spot - and that's the source of your damp patch.

Ideally there shouldn't be any condensation on the underfelt. Is there felt - did you say 'slates' - are they 'bare'? In practice, it's not uncommon to find some cond forming on the felt in particularly cold spells, especially if there's little wind, but usually that is cleared away naturally by ventilation. If it's bad or persistent, tho', that's not good.

Yes, the loft space should be both cold (your loft insulation is working well) and breezy (so you have plenty of ventilation up there, and the loft insulation is NOT tucked in tightly to the corners). If there isn't an actual 'leak and if the ventilation is good - a nice breeze right across the roof void - then you should have no, or very little, condensation up there. If your slates are 'bare', then I'd have expected the ventilation to be very good - a breeze around every single tile! So no cond forming. However, the downside of bare slates is that any driving rain blown upwards under the slates will now get inside, rather than being directed away by the second protective layer of 'felt'. Is this happening in exceptionally wet and windy weather?

What to do? If you are not able to do the necessary crawling to that spot and locate what will be a very obvious damp patch/small puddle, and hence ID where the water is coming from, then you need someone else to do so.

Grenage

I suppose if there was a lof of condensation on the tiles then it could run down to the wallplate.  Can you easily get to the section above the damp and check for water?  What does it look like on the outside?

Arsenal2019

Jeepers_Creepers said:

The good news is that this is not condensation from inside your bedroom - you are doing absolutely the right thing having your windows on vent overnight, and the door open is probably good too - tho' you could probably shut the door if you want as this might actually be allowing fresh warm-moist air into your bedroom from the rest of the house. Your call on that - try both! See if cond forms on your glass.

The patch is FAR too wet and localised for condensation. That is almost certainly coming from above the ceiling. There are actual 'runs' from that patch = that's 'wet'.

Two obvious ways this could happen; one is your roof has failed somehow, so water is getting in past your tiles or any flashing between your house and the adjoining one - ie, there's an external 'leak'. The other is that the wet/moist you see on the underside of your roof slates is trickling down and landing at that spot - and that's the source of your damp patch.

Ideally there shouldn't be any condensation on the underfelt. Is there felt - did you say 'slates' - are they 'bare'? In practice, it's not uncommon to find some cond forming on the felt in particularly cold spells, especially if there's little wind, but usually that is cleared away naturally by ventilation. If it's bad or persistent, tho', that's not good.

Yes, the loft space should be both cold (your loft insulation is working well) and breezy (so you have plenty of ventilation up there, and the loft insulation is NOT tucked in tightly to the corners). If there isn't an actual 'leak and if the ventilation is good - a nice breeze right across the roof void - then you should have no, or very little, condensation up there. If your slates are 'bare', then I'd have expected the ventilation to be very good - a breeze around every single tile! So no cond forming. However, the downside of bare slates is that any driving rain blown upwards under the slates will now get inside, rather than being directed away by the second protective layer of 'felt'. Is this happening in exceptionally wet and windy weather?

What to do? If you are not able to do the necessary crawling to that spot and locate what will be a very obvious damp patch/small puddle, and hence ID where the water is coming from, then you need someone else to do so.

That reply is brill thank you. 

I shall certainly dry the door open that may help. 

I have been up into the attic and can see that there is no felt, and that it is just bare slates. The slates look to be damp/condensated.

yes, I would say that the dampness / wetness is occurring mainly when the weather has been exceptionally cold, or really wet; as it has been recently.

I couldn’t get right to the edge of the wall whilst I was in the attic. I took videos with my phone to record the spots I couldn’t see/reach, and didn’t notice any puddles as such. In addition, the insulation was not right up to the edge of the wall- allowing ventilation around the edge of the wall

would installing roof ventilation help?

Arsenal2019

Grenage said:

I suppose if there was a lof of condensation on the tiles then it could run down to the wallplate.  Can you easily get to the section above the damp and check for water?  What does it look like on the outside?

I couldn’t get right to the edge of the wall as I couldn’t fit due to their being 3x2’s in the way but I couldn’t notice anything when I was up there. Perhaps I should have someone who is smaller to go up?

from the outside , there doesn’t seem to be anything as such which would indicate why this is happening. 

Grenage

You can always duct tape a phone to a stick and try to take a look that way.

If it is just excessive condensate then ventilation is the main key; stopping moisture-laden air from getting up into the loft from below is the second thing to check - a snug loft hatch etc.  Such gaps are normally visible from below, but sometimes you can have big openings from old pipework in airing cupboards or the like.

Arsenal2019

What do you mean by the second paragraph ? Is that in agreement with a roof ventilation?

Grenage

Yes indeed, you want decent ventillation across the roof space - you also want to avoid avenues for air inside the house to make its way into the loft space (where it could cause condensation).

Jeepers_Creepers

Aresenal2019, first, the bedroom door thing. I'm just saying that windows open overnight is good, but the door is your call - I'm not sure if it helps condie problems or not. HOWEVER, it ISN'T the cause of this damp patch - that is NOT internal condensation - it's water from above.

Grenage's idea is cool - tape your phone to a pole or stick, set it to record and take it over that corner - shine a torch there too for light. If you're lucky, it'll be obvious where the water is coming from. It'll almost certainly be either (a) that moist/wet you are seeing on the underside of the slates slowly trickling down the roof slop to end up there - and then through to your wall, or else (b) it's coming through from outside, either at that spot or further up - and then trickling down the roof to that spot.

I suspect it's appearing at that point simply because it's the lowest part of the roof, so that's where water will likely end up.

If it's from the moist/wet underslate, then that begs a further two questions... (1) is it due to condensation forming on the underside of the slates, or (2) is it rain being blown in up and under the slates - which would normally be taken care of by a layer of felt (a secondary defence system).

For (1), you need two things to happen. First, warm moist air from your house would need to be getting up there in the first place - that's where the condensation comes from. Is your loft hatch sealed? Or is there a steady draught getting up past it and into the loft? You have loft insulation there - that's good. The other thing you'd need for condensation forming up there is for the loft space to not be ventilated. I'm imagining that your loft is perfectly fine for ventilation - the insulation is kept nicely away from the eaves (which is where most ventilation comes from - grills in the soffits) but also because you have no felt! There must surely be a HUGE amount of air getting it past ALL these slates, which SHOULD mean that they are kept dry inside.

So, I just can't see that it's down to condensation - tho', of course, it could be.

For (2), this is one reason why felt is fitted before the slates. In exceptional circumstances - very gusty and driving rain - the rain doesn't just land on the roof outside and flow safely away downwards, but is instead blown back up the roof so it gets under the slates and is blown right inside the loft. Usually not a problem, because you have a layer of felt there to catch it all and direct it outside into the guttering at the bottom. But you don't have felt...

It's all guesswork - if your camera doesn't help ID the cause, then you need a pro. (And you'll likely need a pro in any case to fix it...)