Hi @PigletJohn damp issue, please help!

[Saz909]

Hi @PigletJohn I'm wondering if you (or anyone else with the knowledge!) can help with my damp issue.

We live in a converted barn (converted roughly 1980) and for the most part it is very solid - no leaks etc. However, we have one patch of damp in our downstairs room which has been there since we moved in 7 years ago. When we moved in, the original wooden windows were rotten so we thought this could be cause and there were replaced. To be honest I'm not sure how much worse the damp has got during those 7 years as I don't have pictures to compare, but as you can see the plasterboard behind the skirting is now rotten.

The affected section of wall is adjoining our neighbours property but the front of their house is elevated over 1 meter above ours and is set back too (so the affected wall of our house is effectively next to a void which can't be seen or accessed. As soon as the wall of our house meets the start of the house next door, there is no damp.

I went and had a look at next door's bottom bricks in the affected area (about 1m above our floor) and there seems to be mortar missing, so water is possible going straight down into the void where the bottom or our wall is - do you think this could be repointed to solve the problem? Or would the moisture then be trapped and make it worse?

Sorry for rambling I am not sure if any of this makes sense but hopefully someone can help!

Pics attached are of said damp and neighbours wall.

Thank you!

So that black pipe, is on the outside of the same wall as the damp, but will be about 1m higher?
You say ‘void’, but is it a void because it looks like it’s got concrete on top.

@C4tastrophe yes that's correct, it's on the outside of the same damp wall but about 1m above it.

It's quite hard to explain because the house next door is up a few steps which is why we are further down than they are. When I say 'void' you're right, I actually am not sure what is under the brick wall pictured because it's not visible - it's just that the damp is only in the section of wall which runs alongside our neighbour before it reaches the front of their house. The section alongside their house is completely fine.

Also realised the brick picture isn't that clear. The black pipe is the bottom of the wall and the concrete under the black pipe is my neighbour's patio. When touching the very bottom of the wall (by the pipe) it feels damp

So the wall in your house which is damp, has ground/ earth the other side of the wall?

There are two FB groups which are very helpful with this sort of thing. I'd certainly ask on both of them. They are:

Traditional and Listed Building Advice
Your Old House UK - Repair and Conservation

What is under the concrete on your neighbours side?

If it is earth you could try stripping the plaster back on your side of the wall and replastering with lime plaster. That will allow the moisture to come through the wall and out and into your house but without damaging the wall. You will need to use vapour permiable paint over the plaster.

Only other alternative is tanking the wall like you would in a basement.

Also I think it is @pigletjohn

@CutesyUserName thank you I will join those!

@Geneticsbunny thank you for your suggestions - I have no ide what is underneath, it could be earth or concrete, but because there's no way of seeing down there it's impossible to know.

I hope you get on well with the neighbors!
The best solution is dig out their patio until you get well below your ground level, so say 1.5m from patio height. Put a membrane against your wall, and if necessary a ground drain at the bottom, back fill the hole with stones (whatever is the correct name for aggregate that will allow immediate drainage with no horizontal travel) and relay the bit of the patio, keeping a 100mm gap at the top between the slabs and your wall.
I presume there is a wall that ‘holds in’ the patio that also joins your wall? Does it have a gap or vertical DPC ?

I think you may need to add a French drain along that wall.

www.restorationuk.com/about-restorationuk/restorationuk-news/french-drains-explained-how-they-work-and-why-you-need-a-professional

Also to mention, that brick bond suggests a solid wall. For some odd reason, it looks like someone has had silicone injections in the course above the black pipe, which would be half way up your wall. Seems odd!
When/if you dig down, you can repoint with a lime based mortar the manky bits.
As your plaster board is already knackered, maybe cut a hole in it and see what’s behind?

Thank you @C4tastrophe sounds like I better get speaking to next door 😅 it’s rented so need to speak to the lady who owns it.

do you have any idea if we would be solely liable for the cost or should it be shared? Come to think of it she did mention something about damp to me a few years ago but we had just had the windows replaced so I thought we has fixed our issue!

is this kind of thing ever a structural issue? I.e can it deteriorate the bricks that badly? As you can tell I know nothing about any of this!

this is the wall which holds in their patio. Their patio starts where the fence starts.

That retaining wall is more recent than the barn. Does it touch the barn wall or there is a plastic membrane visible? Your wall should have been protected from damp by the builders. Maybe it was and it’s failed.
Have a look behind the plasterboard, maybe they bitumened the wall or something.
I don’t see how the neighbours would be liable for anything to be honest.

Yes the house next door was not part of the original barn so would have been built in 1980s. Think the barn was originally constructed around 1900.

it’s hard to see because of the fence post but looks like it’s straight on to the wall, no membrane.

our wall doesn’t actually feel wet to touch which seems odd - would you expect it to?

thanks for your help, we will have a go at seeing what’s behind there and report back. We’ve had the odd slug make it’s way through so god knows what else is behind there…

The green algae and moss shows there us a long term source of water, a lot of it. I'd look for a plumbing leak first.

The white marks on the wall are efflorescence, sometime from water in chalky ground but often from a pipe leak. The lime content in hard water stays behind when the water evaporates.

The presence of a pipe next to the wet patch means you need to investigate very thoroughly before saying there is no leak from the pipe.

Thank you @PigletJohn for the reply. That black pipe shown in the photo goes into our phone socket you can see on the inside wall so It’s not a water pipe. As you can see the pipes for our radiators run on the interior wall but none of these are leaking.

I am not sure where the water source could be unless it’s from a pipe or drain underground. Now you mention it next door’s drain does run on a downward slope into the drain in our front garden but I don’t know exactly where. The water company have been on many times to unblock them (old drains) and never mentioned a leak.

Could the moss be from a build up of rain water? If it has no where to run off?

We do have very hard water so not sure if that explains the efflorescence

Efflorescence is caused by wet bricks dissolving the salt inside them and the salt coming to the surface as the water leaves the bricks. So basically it’s a sign of wet/ damp masonry. You will see it on some houses after winter when the brickwork has had a lot of weather on it.

The marks on the wall have potentially been there for some years. As mentioned we had damp in that corner when we moved it - replaced the windows after about a year, put some furniture in the corner and kind of forgot all about it.

It’s only recently I’ve realised how bad it looks, but I will say it’s not wet at all to touch. I’m wondering if it’s been very slow progressing. Would you expect the wall to be wet to the touch all the time for a serious leak/damp problem?

If the water company have bee out 'many times' it suggests to me that there may be old, knackered pipes which need replacing. Freinds have had repeated blockages affecting thre properties upstream of them at times, and the last time a company came and cleared a blockage thay put a camera down afterwards and said they thought there was a collapsed drain. The water company were informed, but have done zilch to date. I'm sure it will keep blocking until they fix it properly.

@BlueMongoose our drains are definitely
old, they apparently have very narrow pipes which is why they’re easily blocked. They have also dug up our front garden before to repair a ‘lip’ in the drain. They have put cameras down every time and the last guy was very thorough so I hope it’s not the drain.

It seems too coincidental to me that the only affected section of wall is the exact location and width of the wall next door adjacent to underneath next door’s patio.

Recently had a patch of damp like that on an internal wall. Despite the excess charge decided to ring our insurance. Turned out it was an escape of water from an underfloor pipe that had eroded. It affected 5 rooms! So ended up with a huge renovation including a new kitchen all paid for by insurance. Not saying this is what it is but I was so happy I rang our insurance company

If you only have one affected section, it is most likely a localised leak. If it was from damp ground it would tend to be at a low level all along the wall, and nit as severe as you show.

If it gets worse after rain it could be a downpipe, gulley, or run off from the patio.

If it gets better when your neighbours go on holiday it could be their bathwater.

If you get wild tomato plants it is sewage. If you get white soap deposits it is from a washing machine.

But I have a feeling it is a waterpipe.

Do you and the neighbours have water meters? Garden taps?

P.s.

Yes, it does look like somebody has injected silicone into the bricks.

This was futile and completely useless

As usual.

Make a note never to allow anybody into your house who sells silicone injections.

Next time it’s raining I will go next door and see if it could be drain pipes etc

We do have water meters, ours is in the front garden so assume theirs is in their patio somewhere. Our garden tap is in the back garden, I will check if they have one.

the silicone injections must have been before we lived here so over 7 years ago, which would suggest there has always been a problem. I thought the whole point of the injections was to stop water rising so it seems odd someone would do it half way up a wall!

if it was from a washing machine/kitchen pipe, would you expect it to get obviously worse each time it’s run? Our kitchen pipe runs under there somewhere but I use the washing machine every day and it seems to stay the same.

If we identify a source of water, would it be enough to get that fixed and then obviously fix the internal problems. Or would the bottom of the brick wall on the outside need to be exposed and repaired too? I.e dig up our neighbours patio