Mould on inside of external wall?

Tinders

Tinders

Tinders

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Hi Guys,

Can any one give me some advise on dealing with light mould on the inside of external wall. Its an old 3 story victorian property and its in a 1st floor bedroom. ive had a look on the outside and i cant see where water could be getting in, so im thinking its an air flow issue, the top corner is bad, which happens to be where my desk and PC are.

I try and keep the windows open as much as possible, but im seeing spots all over the wall, ive wiped the mould off with some HG cleaner, but it reappears after a few months, what would be the best way to tackle this? in a bid to save energy i dont have the heating on much in the room, so could that be a cause? im thinking about putting some battens on and putting some thick insulation on the external walls, would this help or make things worse? i think theres an airbrick, but its plastered over on the inside iirc.

Any advise appreciated.
 
Usually cold temperatures and high humidity cause mould. Do you have a dehumidifier? Costs energy to run though obviously. Un-cover the airbrick, that might help a little. Or just try and help the air move around more, with a fan if necessary.

You can get special paints that are more resistant to mould, might not be cheap but it's only a one-off cost at least. That's what I'd be doing. Just make sure you fully clean the mould off before painting, you can't just paint over the mould obviously.
 
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It's because the walls are cold, any humidity will condense, especially in the corners of the room.

Just keep your house ventilated, manage humidity (e.g. make sure you have a decent extractor in the bathroom and don't just let all the moisture out into the rest of the house after a shower), and zap any spots with mildew killer and wipe it down.
 
We had this in an old house years ago just after we bought it. The mortar was crumbling on the outside as it was on the apex most exposed to the elements. The gutters were leaking, also, making the wall damp. Give the exterior wall a thorough check.
 
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My thoughts are it's unlikely to be an airflow issue, as what would the source of moisture be? Water probably is getting into the wall, making the wall damp and providing a cold damp surface for mould to grow. I would take a closer look to see if you can identify a source of water ingress. Examples of things to check are roof leaks, damaged pointing in the brickwork, blocked or damaged guttering etc.
 
From an initial glance the outer bricks dont look too bad, but thats looking from the ground floor. I can see one or 2 bricks where the face has 'crumbled'. they are solid otherwise, and are good 3-4 ft lower than the corner where the worst mould is.

Its on the 1st floor of a 3 story building, so unlikely to be roof related? The gutters were only cleaned last year after being filled up with a decades worth of crud. but i do remember water used to over flow and run down the wall. Its a house i have inherited so im slowly finding lots of things to fix.

Could/should I put some brick sealant on the outside?
 
Tinders said:
From an initial glance the outer bricks dont look too bad, but thats looking from the ground floor. I can see one or 2 bricks where the face has 'crumbled'. they are solid otherwise, and are good 3-4 ft lower than the corner where the worst mould is.

Its on the 1st floor of a 3 story building, so unlikely to be roof related? The gutters were only cleaned last year after being filled up with a decades worth of crud. but i do remember water used to over flow and run down the wall. Its a house i have inherited so im slowly finding lots of things to fix.

Could/should I put some brick sealant on the outside?
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It's very unlikely to be moisture coming in.

If it's an old building (like mine) with poor insulation, the wall is cold, so any humidity in the air will condense in areas with poor airflow. This is usually in the corners of the room.

This humidity comes from your breath, particularly if you're sat underneath it at your desk.
 
Here some pics before i wiped it over, im basically here most of the day, would insulating this wall help? i was thinking of using battens to create an airgap and then use some 25mm cellotex or similar or i can get an air brick put in, just realised there isnt an airbrick anywhere in this room.:(

p8HRdWP.jpg
TcDWsS1.jpg
 
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The fact that you aren't putting the heating on could be a major contributing factor. If you don't heat the room, then it's easier for water to condense on the wall, and then for mould to grow.

If you touch the wall where the mould is, does it feel wet?

Really needs cleaning and repainting, then keep the heating on a lot more and see if the mould comes back. If it does, then you have a structural water ingress issue. Or, you could get a check done for the structural issue first, but this will be more expensive.
 
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With the mould like that, you don't want to spend too much time in that room, it's very bad for your health.

I would suggest clean (with dilute bleach), redecorate, then heat, and see what happens, but also keep in mind it could be a water ingress issue so monitor closely and get a professional to look at it if necessary.
 
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Airflow.

Even in a new build I experience mould in one of the bedrooms when it's cold outside, if it is kept warm and not ventilated. If you have a trickle vent on a window, open it.

Presumably you keep the door close to help keep it warm?
 
You could try anti-mold paint or mix anti-mould additive to the paint you want to use. Doesn't stop the room from being damp but should reduce or eliminate the mould in that area.
Used it years ago in a previous property and it seemed to do the trick.
Still best to sort out any air flow or heating issue.
As touched on above, it may look a lot worse under any wallpaper.
 
I peeled some paper back in the top corner today. Thankfully no spots behind there, it did clean off really easily with some HG foam mould cleaner.

Im thinking if its worth getting a airbrick put into the room, maybe even 2, near the corner of the room, its either that or run a dehumidifier once a day, need to look into the efficiency of them, as my bills are already sky high.
 
Just an update. Ive been doing a fair bit in the house this summer and finally got round to tackling this room. After stripping the paper, most of the wall behind was ok, but there was some bit of small mould on the plaster. One thing i noticed was the rubbish state of the guttering, as it was hugely blocked, the water was running down the wall from the 2nd to the 1st floor. So im guessing thats part of the problem. Its a north facing wall, so it gets the worst of the weather

Ive also come across some cream made by Stormdry its £120 for 5l, but it seems to help with moisture ingress on solid brick construction, whilst still allowing the wall to breath, might even add 2 air bricks in the room, belt and braces and all that :p
 
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Tinders said:
Just an update. Ive been doing a fair bit in the house this summer and finally got round to tackling this room. After stripping the paper, most of the wall behind was ok, but there was some bit of small mould on the plaster. One thing i noticed was the rubbish state of the guttering, as it was hugely blocked, the water was running down the wall from the 2nd to the 1st floor. So im guessing thats part of the problem. Its a north facing wall, so it gets the worst of the weather

Ive also come across some cream made by Stormdry its £120 for 5l, but it seems to help with moisture ingress on solid brick construction, whilst still allowing the wall to breath, might even add 2 air bricks in the room, belt and braces and all that :p
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Get a Drimaster, best thing we ever did in a house that suffered with damp and/or condensation. We do still get the odd bit now and again but pretty much solved, the only corner of a room where it has not happened has been where my PC is due to the fans moving the air.

This doesn't negate the fact that you need to remedy as best you can any damp issues.

Also if I was going to insulate the walls inside id do this -
www.youtube.com

Using Adhesive Foam To Attach Insulated Plasterboard

First project in the bedroom is to insulate the outer wall of the house with insulated plasterboard attached with insta-stik foam. There are a lot of differi...
www.youtube.com www.youtube.com
 
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