Mould on walls

[Reluctantadult]

Been in my house 7yrs, it's a 1940's mid terrace ex council house with a tunnel through to the garden. We get mould on the outside walls, caused by condensation I think. Just found more behind my daughters bed. Have rearranged the room so nothing is now against that wall (not great for the layout 😕). Cleaned it all off work mould spray. We got cavity wall insulation last year. We run a dehumidifier 12hrs a day. What else can we do?! Obviously it's not good for kids health. Would window vents help?

Ventilation and heating definitely help. You can put things on that wall but just not right up against it so there is no air circulating. Just pull the furniture out. Open the windows as much as you can though difficult in this weather of course.

We have had the heating on, albeit less than normal ours still on a good amount. With her bed away perhaps we can keep the window open a crack at night. When we've got the dehumidifier on in the day the windows are shut.

Are your windows wet in the morning?

Ive been going round mine everyday when I get up with a small squeegee and towel, getting them all dried off. Probably get about a pint of water/condensation a day off them, has really helped this winter for damp buildup.

Check for leaks.

Don't dry washing inside.

Ventilate as much as you can.

We have a 3 bed 1940s semi and suffered with awful mould upstairs. We had a positive input ventilation system fitted 2 years ago and after removing the mould it has never come back! It's one of the best things we've bought for our house. The system and cost of fitting was £600.

We have a PIV system and it hasn't made much difference. Dreadful black mould, cleaning with white vinegar every day, dehumidifier.

We’ve just installed a positive input ventilation in our Victorian terrace and it’s eradicated this issue for us within 2 days. It cost about £500 for the equipment and an electrical socket being fitted for it in the loft.

Ah no that's a shame. We had a damp surveyor round as I was pregnant with my second and his room was the worst of all. He said it's all about ventilation and keeping the house heated. We do have the heating set to 17 in the day and 15 at night which of course is not cheap anymore but I really don't want the mould to come back.

Yep we do this every day.

We have to dry washing inside in this weather. We do use the tumble drier sometimes which is downstairs away from any problem areas.

One for and one against a positive input ventilation system which I haven't heard of so will look up.

We have everything slightly away from the wall to allow for air circulation.
The only time we had damp issue was when we forgot to air properly in a morning. And that was with same level of heating as any year.

If you have no leaks etc, like gutters since it's on extrnal, try getting into habit of opening all windows (at least upstairs) in a morning for 15 min and then heat. Long open windows don't have effect like short and brutal airing.

There is a reason some places have this in rental contracts.

I get mould on 1 bedroom wall upstairs. Just keeping the window open a crack permanently seems to keep it at bay and almost eradicates the condensation on the window in that room.

I'm trying leaving windows open a crack tonight. See how cold everyone is!

I've heard negative things about cavity wall insulation contributing to internal condensation but I can't remember the science. I've heard people sometimes get it taken out when they have issues. @PigletJohn might know something about it.

We had issues before the cavity wall insulation to be fair. I had hoped it would help as walls might be less cold. But doesn't seem to have.

Agree with brief airing in the morning - fling windows open for 20 minutes - and drying moisture on windows. Do both having had problems in the past and don’t have any issues now.

Mould is caused by damp. You can ventilate the water vapour out, but if you drape wet washing indoors you are adding a tremendous load of water to the house

If you can't stop doing it, does your bathroom have an extractor fan that works? If so you can use a line or rack in there with the fan running continuously and the door and window SHUT. This will draw the water vapour outside and create suction that prevents it diffusing through the house.

CWI does not cause condensation (which is water) because it does not create water. It makes the walls warmer by reducing heat loss and thus less receptive to condensation. If the air in the room is damp, it will now condense on some other cold surface, typically the window.

In some cases houses have defective damp walls, or are in exposed places subject to intense driving rain , or are wet from rain penetration or leaking gutters. Adding CWI without repairing the defects can reduce their ability to evaporate away the water, which can become more noticeable. CWI installers are now required to inspect walls for defects and will often refuse to install CWI in houses at risk of damp

I have to dry things that cannot be tumble dried inside because it won't dry outside in this weather. I run a dehumidifier next to the washing, on a drying washing setting.

The way I used to do it was putting it in the bathroom, window open, door shut. But to be honest it's in the way. I could go back to that but I'm not sure it's any better as we get mould every year.

Having the windows open a crack last night has made a big difference to the condensation on the windows. My daughter claims she was cold but only after she found out about the window! More concerned about my son as his feet are under the window, can't move the bed as the room is tiny. But I know lots of people prefer sleeping with the window open don't they!

I dry inside as well and it causes no issues. Not in the rooms though! Figuredd out pretty quickly that that would be disaster if long twrm. Landing oroved the best!
No damp in the rooms, it just disoerse? It's not drafty, maybe a tiny bit, but it's just the typo of soace which takes washing drying well. Bedrooms did not.

Bed socks?!

2 in a tiny bedroom is going to cause a lot of condensation from breath, so the window open just a little really will help control the mould.

I dry washing in the house too. I part dry outside if possible, unless it's raining/particularly damp. I've never had any issues in the room the washing is in, only that bedroom, so I'm guessing it's just the coldness of the wall overnight combined with breathing!

I sleep With my window open a tiny bit for most of the year always have done.