damp diagnosis 4th floor flat

Hi,
I have a couple of damp issues in my top (4th) floor flat. - a few mouldy patches inside cupboards in bedroom on outside wall, one side of room is from the floor upwards but also on other side of room in top cupboard by ceiling. - a couple of dark mould patches, and wallpaper crusting away from wall (up to 0.5m from floor), on internal wall of same room, other side of wall to bath, about 1m from the outside wall. I have just renewed the seal around the bath - it was a bit damp under the bath and has previously flooded. - a football size patch of discoloured wall, looks like the start of mould, about 1.5m from floor, backs onto middle of shower tiles
I would like to get an expert opinion to confirm the causes of these, and some advice on whether to just leave to dry or treat somehow. Is one just the leaky bath and the other condensation, or anything due to leaks from outside - it's hard to investigate from outside being so high up.
What is the recommended course of action? - pay for a visit from a surveyor, building inspector, damp specialist company...?
Thanks a lot, Andrew
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I`m no expert (crap at DIY), but a bit more info might be useful.
Is the flat bought or rented - if bought, do you pay some sort of maintenance fee (common in flat situations) ?
If so, it might be worth getting the people who are supposed to maintain the building to check for problems with the roof and/or guttering.
Are there any obvious causes for damp from outside, i.e. the gutters blocked / overflowing ?
Also, try hitting google with "mould spores health"...
Poor ventilation can sometimes encourage mould, but by the sounds of it, the airflow around your affected areas don`t fall under this category (we once had some in a built in wardrobe where clothes remained pretty much static against an outside wall)
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Andrew wrote:

Most likely condensation, also possibility of penetrating damp due to guttering discharging onto wall. If your damp is spread about the place, it almost has to be condensation. For condensation the simplest solutions are cut down on steam produced, eg dont dry clothes in the flat, ensure ventilation adequate, and use a humidistatic dehumidifier.
Beware of damp treatment companies.
NT
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Agree with previous poster, multile damp patches with no obvious connection suggests condensation.
Obvious sources are cooking, baths/showers, washing/drying clothes, and water or drainage/sewage pipe leaks.
You haven't told us about the age of the building or the style of construction - victorian/modern? flat/pitched roof?
Roof leaks/penetrating damp tends to be localised with characteristic ceiling/wall staining - and I think we can rule out rising damp in your case!
Dehumidifiers can really help in the very short term, but you need to find and stopor the source and/or improve ventilation.
Do any of your neighbours have similar problems?
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snipped-for-privacy@gglz.com wrote:

heh, I wouldnt put it past some dpc company!
NT
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thanks all for your responses. The property is about 1970
Testing under the bath, the wall is still a bit damp from an earlier leak. Need to get on the case with drying it out more properly. Any suggestions - just get a convector heater on it or is a dehumidifier going to make a difference. I don't know how effective this will be at focusing on a particular area as opposed to a whole room- and hard to fit under the bath to get close to the damp wall...
I tried scrubbing the inside wall of the cupboards with bleach but very hard to shift it. I wanted to repaint it, maybe with some anti mould paint, but need a way to get rid of the mould beforehand.
I'm going to fit an extractor fan to the bathroom to hopefully reduce condensation in the future.
Thanks a lot, Andrew
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