What the hell is causing this damp?

[Cloo]

Right, so this fucker has been developing in the corner of our bedroom window bay (1st floor) for a while, didn't see it at first as it's behind some furniture. Taking ages to do anything about it because it takes ages to get a builder in and to get them to quote, and we've had different views on what the cause might be:

• Window sealant - we allegedly had that redone last summer though I wasn't there when the guys did it and I can't see any evidence of it, problem continued to get worse afterwards
• Something to do with water collecting on wide, flat stone outer window ledge

Other possibilities I'm wondering about
- Something to do with brick pointing?

It's now started to develop on the bay window on ground floor, same side.

I'd be interested if anyone has had similar? I am wondering about just getting someone to chip away the upstairs plaster, which clearly has to go anyway, to see if that sheds any light. It seems to have started from bottom going up if anything.

 

[two sheds]

leak in guttering above outer window ledge?

 

[Epona]

Are you able to safely get a photo of that corner from the outside of the building?

I am not in any way a damp expert, but that would allow people to look at the pointing and window to wall interface from the other side which might help with a diagnosis.

 

[Epona]

BTW I have similar looking damp patch under the bottom right corner of my bedroom window, the plaster is actually wet and crumbling, which is clearly a sealant issue - I can't get to the outside of the building to seal it from there so when we get some dry weather I'm going to pull off the damp plaster (masked up ofc. cos of mould) and have a look to see if I can fix it with some mastic (or expanding foam, if there's a large gap) from the inside.

Not saying that is what is wrong with yours however or offering advice on how to fix it, just relating my own tangential tale of damp!

 

[Cloo]

I could do - there doesn't seem to be any visible problem, though I note the paint has been peeling away from the base of the masonary around that corner of the window. There is an overflowing gutter which I wondered about, but neither builder brought it up. On balance it seems the most likely thing - some (very expensive!) roofing guys were supposed to take a look at it while they did some work (including the window sealing) but evidently they didn't - although at least they cured a horrible leak at the back which just turned out to be where the chimney breast had been removed by the chimneys weren't capped; that has stopped getting worse now.

Maybe next time it's tipping down I should film the gutter so we can show it to someone.

 

[Epona]

Also I would be inclined to think that if it was in the upstairs first and working its way down the building then look upwards for the problem - guttering possibly as two sheds said.
Was there furniture in front of the damp place in both rooms? Cos that can cause issues with condensation forming behind furniture especially if you've been trying to save on heating costs this winter - cold external wall with no air circulation behind furniture is a typical hot spot for condensation type damp.
However the fact it is in that same corner in both rooms starting in the upstairs would suggest something coming downwards.

 

[Epona]

I could do - there doesn't seem to be any visible problem, though I note the paint has been peeling away from the base of the masonary around that corner of the window. There is an overflowing gutter which I wondered about, but neither builder brought it up. On balance it seems the most likely thing - some (very expensive!) roofing guys were supposed to take a look at it while they did some work (including the window sealing) but evidently they didn't - although at least they cured a horrible leak at the back which just turned out to be where the chimney breast had been removed by the chimneys weren't capped; that at least has stopped now.

If the overflowing gutter is above that area then that could well be the root of the problem - probably needs a clean out.

 

[Idaho]

Definitely agree we need an outside pic!

Could possibly be a rotten window/frame which is allowing water to drip onto the inside of the cavity wall.

Is that internal wall lathe and plaster? Sometimes on the outside of a bay it's tile cladding on outside and lathe and plaster on the inside. Drafty and prone to water ingress.

 

[Cloo]

I suspect it is internal lathe and plaster - one builder suggested taking the plaster off and putting in some sort of membrane before replastering; his theory was water gathering on the fairly flat windowsill. But I think the reason it's gathering must be the gutter.

 

[seeformiles]

We had something similar. - turns out it was that the area being splashed by.a leaky drainpipe and a crack in the gutter, A pretty inexpensive fix ( just a wee bit of plastering) Good luck.

 

[StoneRoad]

Without an outside pic it's difficult to tell, but I would suspect the guttering / downpipes, especially if there is an overflow.

Water can also find a very long-winded route between where it shows up, and where it is getting in ...
Plus something bridging the cavity can make that worse [I once saw some pics of a cavity wall with a lot of mortar on the wire ties, amongst other problems].
Could be a cold spot and poor air circulation making the situation worse / more noticeable.

 

[Cloo]

It's sounding to me like builders are overkill and what we might need is just a gutter-sorter-outer and a replastering job.

 

[two sheds]

Worth using hb type mould remover, and dehumidifier to dry it out once source sorted?

 

[ddraig]

Had a bit of this at front of house behind a sofa, aired it out and dehumidifier for while, also mould spray
Good luck

 

[two sheds]

yes I've sprayed a good couple of walls which had suffered this winter. Some of it was black and I thought the mould remover would have damaged the paint but it didn't. I'm moving the dehumidifier (desiccant, I may have mentioned this before) round critical rooms which is helping. I should probably insulate those walls properly before next winter.

 

[Cloo]

Interesting about a dehumidifier and that black mould can come off - the damp plaster does seem to be in place and not peeling/bubbling so maybe it could be solved. I bet if I ask street whatsapp group someone might have a dehumidifier. Both the spots are behind furniture, so just sorting cosmetically could be sufficient, and it's worth trying before the expense of replastering. I know someone recommended a gutter guy on our whatsapp group last month as well so I'll give him a try.

 

[Callie]

Do you have someone clean your windows? They sometimes fix guttering or clean them

 

[two sheds]

Do you have kids? You can sometimes get them to climb up to the guttering.

 

[MrSki]

Worth leaving an inch gap between the wall & furniture to allow airflow.

 

[Cloo]

Do you have someone clean your windows? They sometimes fix guttering or clean them

I think we might need some guttering rework, as we've cleaned them a few times but problems keep returning

 

[Callie]

I think we might need some guttering rework, as we've cleaned them a few times but problems keep returning

I think it's an annual job minimum. Stupid trees. Mine need doing, the front right corner is very splashy. Not as bad as my neighbour thought, theirs is like Niagara falls and it huts their bins and goes all over the wall :/

 

[WouldBe]

Do you have kids? You can sometimes get them to climb up to the guttering.

And get them to come back down the chimney, cleaning is as they go.

 

[two sheds]

Indeed, gets them out of the house, they learn a new trade ...

 

[Cloo]

Roofers came today - he didn't have time to look at the beam but he was pretty certain it was just wet due to some missing tiles he'd spotted and should dry out once that's fixed and definitely the corner gutter likely to be messing up the bays. If their quote's good reckon I'll get them in and ask them to take a look at the roof while up there and quote us for some repair/overhaul including the chimney stack they noted is looking a bit unhealthy, which we have been aware of.

 

[bellaozzydog]

Guttering is always a good main culprit

Is your guttering “falling” correctly, you need to go outside and look at it when it’s tipping down

I altered a few bits of guttering angles and my first floor damp patches just dried up. All it takes is a flow of water down a wall at some point

 

[Aladdin]

We had similar problem. Turned out the gutter was the problem. Heavy driving rain filled the gutter faster than it emptied...and unfortunately water spilled in behind the gutter and in nder the roof....which came in down the bedroom wall. Plaster and all bubbled and there were some very damp patches. It's sorted now after a wider gutter was put up ...and everything has dried out. The yucky plaster has been flaked off but its taking ages to get a plasterer in. It looks crap but the problem has been sorted. Gutters and not having effective gutters can cause problems.

 

[Cloo]

Another point damp might be getting in is where this decorative feature at the apex of front eaves has apparently fallen off (don't know the name,, we call them tchotchkes after the Yiddish for 'bric a brac' or 'doodah) see below on houses opposite (one on far right is broken)



So may need to ask a) where do you buy one? And b) can we get someone to custom make one that looks like a TARDIS?

 

[two sheds]

.

 

[two sheds]

I read this which is interesting:

Mouldy Britain: a foolproof guide to rescuing your home from damp

The risk of damp and mould is rising fast, bringing with it serious health implications. Here is an expert guide to eliminating the problem – without paying a fortune

www.theguardian.com

It says though that dehumidifiers aren't generally recommended because they don't solve the actual problem and because they consume electricity. Doesn't apply to my situation I don't think - the Cornish atmosphere is very damp which is part of the problem, and solar panels mean it won't cost to have it running in the day in summer, see whether I can dry the place out properly. And desiccant dehumidifier blows out warm air that's got to be like heating the place which they do recommend. And using it temporarily to dry out a corner has to be good.

 

[clicker]

Another point damp might be getting in is where this decorative feature at the apex of front eaves has apparently fallen off (don't know the name,, we call them tchotchkes after the Yiddish for 'bric a brac' or 'doodah) see below on houses opposite (one on far right is broken)

View attachment 366921

So may need to ask a) where do you buy one? And b) can we get someone to custom make one that looks like a TARDIS?

Finial? Maybe.