Damp Wall Treatment

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markjay

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We have use of a flat that isn't ours.

The wall under the bay window is constantly wet.

I am unable to tell if the water ingress is from the window seal or the wall itself (it's on the fifth floor and access to the outside wall is limited).

The issue is that mold keeps reappearing on the damp wall.

I am unable to effect any permanent repair, the owner is abroad and doesn’t really care about the damp wall.

What treatment will prevent the mold from reappearing? I am less bothered about aesthetics, just want to avoid the mold.

Will something like this work?


As always, your advice will be highly appreciated.
 
We have use of a flat that isn't ours.

The wall under the bay window is constantly wet.

I am unable to tell if the water ingress is from the window seal or the wall itself (it's on the fifth floor and access to the outside wall is limited).

The issue is that mold keeps reappearing on the damp wall.

I am unable to effect any permanent repair, the owner is abroad and doesn’t really care about the damp wall.

What treatment will prevent the mold from reappearing? I am less bothered about aesthetics, just want to avoid the mold.

Will something like this work?


As always, your advice will be highly appreciated.
That’s the cheapest ’cover up’ option MJ.

The problem could be caused by many different factors. But there are so many variables. Wall construction, window frame material (timber/UPVC), plaster make up (plasterboard/float & skim, cavity insulation type (if any). Details of the above will help and a few photos if possible.

If you’re going to use the Ronseal option then make sure you paint directly onto plaster and not wallpaper.
 
Whenever the mold reoccurs hit it with Cillit Bang Black Mold Remover. I live in a 200 year old cottage with solid stone walls. Between late October and early April the damp atmosphere means that we often suffer with black mold around the stone window frames. Cillit bang is magical. Just spray it on and leave it ten minutes. The mold normally just disappears with no elbow grease necessary.

its only a couple of quid a bottle and lasts us the whole winter.
 
Well can you open a window and look down the outside wall for damage,how old is the flat,if ancient it will not be a cavity wall so any damage to the wall may cause this damp ingress.
 
If it's from outside the damp will migrate outside the area covered by the damp seal, you need to fix the problem and then seal the wall with a liquid damp seal. If it's from inside it will come back whatever you do until you increase heat and ventilation.
 
I have a conservatory with a sold 10" wall and that has only once in 5 years shown mould on the inside when very strong winds produced horizontal rain. I washed it down with bleach and it hasn't returned. If yours is wet every time it rains then I'd be looking for another defect perhaps missing mastic where the window frame abuts the brickwork. Any sort of treatment on the inner wall surface may help with the mould but the wall behind it will still be wet.
 
Buy an Ebac dehumidifier and put it in there, it’ll blow your mind how much water they pull out of a damp atmosphere.
Did that in our first house , a listed 'cottage' one up one down place , no central heating no double glazing 150 years old, The Ebac pulled 9 litres in 24 hours !! this went on for days and gradually dropped off to a few litres a day. Ended up digging up the ground floor , pouring solid and all the other stuff that goes with it. Nightmare.
 
Did that in our first house , a listed 'cottage' one up one down place , no central heating no double glazing 150 years old, The Ebac pulled 9 litres in 24 hours !! this went on for days and gradually dropped off to a few litres a day. Ended up digging up the ground floor , pouring solid and all the other stuff that goes with it. Nightmare.
A few years ago I plastered a kitchen for a customer. I set up my dehumidifier for over the weekend so I could get the room painted on the Monday.

I politely asked the customer if he would empty the machine as and when the reservoir was full. I returned on Monday, next to the dehumidifier was 2 black buckets full of water. I asked him why they were there and he replied: ‘I used the buckets for the water from the dehumidifier’ :wallbash:
 
A few years ago I plastered a kitchen for a customer. I set up my dehumidifier for over the weekend so I could get the room painted on the Monday.

I politely asked the customer if he would empty the machine as and when the reservoir was full. I returned on Monday, next to the dehumidifier was 2 black buckets full of water. I asked him why they were there and he replied: ‘I used the buckets to empty the dehumidifier’ :wallbash:
:D
 
^ :doh:.
Obviously your fault Ant for not impressing on the owner the buckets had to be emptied😆
 
Buy an Ebac dehumidifier and put it in there, it’ll blow your mind how much water they pull out of a damp atmosphere.

Given that I can't fix the water ingress... drying the wall as a one-off won't achieve much, I think?
 
That’s the cheapest ’cover up’ option MJ.

The problem could be caused by many different factors. But there are so many variables. Wall construction, window frame material (timber/UPVC), plaster make up (plasterboard/float & skim, cavity insulation type (if any). Details of the above will help and a few photos if possible.

If you’re going to use the Ronseal option then make sure you paint directly onto plaster and not wallpaper.

The wall feels like painted plasterboard to me.
 
Whenever the mold reoccurs hit it with Cillit Bang Black Mold Remover. I live in a 200 year old cottage with solid stone walls. Between late October and early April the damp atmosphere means that we often suffer with black mold around the stone window frames. Cillit bang is magical. Just spray it on and leave it ten minutes. The mold normally just disappears with no elbow grease necessary.

its only a couple of quid a bottle and lasts us the whole winter.

Thanks. Yes I can remove the mold from time to time, what I am asking is if I can stop the mold from coming back, knowing that the wall will get wet again? By sound of it, this isn't possible...
 
Given that I can't fix the water ingress... drying the wall as a one-off won't achieve much, I think?
Leave it in there until the room is “dry” and it should help you find the root of the leak; even if it actually is simply poor circulation.

I live in a 1920’s house and we leave ours on all the time, it makes a massive difference to the amount of moisture in the house from the multiple baths and showers taken to the central heating being on XYZ hours a day during this current weather.
 
Well can you open a window and look down the outside wall for damage,how old is the flat,if ancient it will not be a cavity wall so any damage to the wall may cause this damp ingress.

On the outside of the wall there's a metal construction extendinf up to about a foot away, that covered the exterior - this is all I can see. The sheet metal covering will have to come off in order to inspect the outside of the wall, and this will require scaffold to the fifth floor...
 
Leave it in there until the room is “dry” and it should help you find the root of the leak; even if it actually is simply poor circulation.

I live in a 1920’s house and we leave ours on all the time, it makes a massive difference to the amount of moisture in the house from the multiple baths and showers taken to the central heating being on XYZ hours a day during this current weather.

Thanks, this could be an option.

We probably won't be using the flat for long so I'm limited in what I can to fix the problem.
 

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