Mould! Please help!

[Bootsalex]

I have mould growing in every room in my house!!!
The house is heated well, log burner and we have central heating on for a few hours a day when really cold. I open windows every morning to air the house out.
It's our 2nd winter in this house only. We moved in and gutted the place...including re-plastering all walls.
I've cleaned it off the walls using bleach but everywhere I look there seems to be a new patch! Its stressing me out and I'm scared of it being in so many rooms because of our baby.
Anyone got any ideas to help?
Thanks x

[CheeseBadger]

Place marked in case any useful advice comes up. We have the same problem in two downstairs rooms. We've always assumed that it was because out 120 year old house was built without a DPC and has solid walls. Could your place be similar?

[PigletJohn]

the mould is growing because the walls are damp. When were they plastered, and when were they emulsioned?

The most common cause of damp and mould in UK houses is condensation caused by draping wet washing around the home. Do you do that? Have you got an effective bathroom extractor?

[Bootsalex]

We had them plastered about a year and a half ago? We bought the house in April and moved in September so between then, they were plastered and painted.
I dry washing outside whenever possible and use a tumble dryer when not possible. Some clothes are dried in the house but I tend to put in 1 room and have a window open (if its not too cold) or in front of fire at night. It isn't a huge amount of washing though.
The house was built in the 50's so not that old....and I don't know about DPC as I asked about cavity wall insulation recently and British Gas said they wouldn't do it because they could see no evidence on the outside of the house of a DPC.

[PigletJohn]

OK, so the plaster should have dried out by now, so I think there is another source of damp.

if it is 1950's I would be shocked if there was no DPC; however it is possible that the ground level round the house has been raised above it, e.g. with flowerbeds, patio or drive. I notice that BG are very cautious of doing anything that could leave them with liability for an expensive remedy. If the house is rendered, or you think the ground level has been raised, you could ask an experienced local builder to excavate or chip away for a look. If local, the builder will be familiar with houses like yours, put up in the same way by the same builders.

Do you have an effective bathroom extractor?

[Bootsalex]

Yes, BG said they give a 15 year guarantee with cavity wall so they basically didn't want the risk.
I wouldn't say the ground level has been raised, theres no patio or anything you've suggested?
We don'd have a bathroom extractor but the window is always opened during (if warm) or straight after showering and the door is shut until its clear. Do you think that would produce enough moisture to have mould in every room?

[PigletJohn]

don't know. It might if the wind blows in through that window.

Have you got a water meter?

Is the ground floor concrete?

[MrsFlorrick]

Could your cavity wall already have cavity wall insulation? And either there was no dpc or dpc had failed causing the cavity wall insulation to essentially help damp across into your house?

Just a thought.

[Sizzlesthedog]

Bloody mould. My lovely house never had mould til I rented it out. Now there is mould everywhere. Once it's in and growing, I don't know if there is a way to stop it.

[MrsFlorrick]

Sorry. Wanted to ask.
Is the mould only on external walls?

Or internal walls too? Ie walls between two inside rooms?

If it's only on the external walls, you need to consider things like rising damp, failed cavity wall insulation, leaky blocked gutters or failed guttering/downpipes.

If it's on internal walls too, then you need to look at how well your home is ventilated etc as Pigletjohn says.

People breathing, showers, baths, cooking and wet laundry produces amazing amounts of moisture in the air. Each person expells something like 20l of moisture per 24hrs.

So if your rooms are small with low ceilings and you don't ventilate enough, it could happen. Also if in conjunction you don't heat the house enough.
The irony is that ventilating a house works best with also heating it well.

It does sound like an external cause given the amounts of mould you're describing.