Is this damp or something else?

muckybutt

Black mould is nearly always a sign of poor ventillation, too much damp / moist air inside coming to rest on a cool surface will condense and eventually you get black mould.

You need to improve the ventillation or get a dehumidifier in. Black mould if not treated can lead to allsorts of respiritory health problems.

elsien

Brallaqueen wrote: »

I would not think it is caused by condensation. Condensation normally happens around window sills, behind furniture and even inside it. Any mould that appears that high up and away from large furniture would make me think leak from upstairs, gutter problems or rain getting thorugh the brickwork.

We've had a problem with black mould appearing along top of the wall/ceiling edge on an outside wall. I am 99.9% certain it's a condensation problem due to the person whose room it is refusing point blank to open a window the majority of the time. It's a bungalow so easy to check the guttering and there's no sign of water getting in through the roof. I bleached it about 18 months ago and it wiped straight off, persuaded the person to start opening the window which they did for a while but now we're back to closed window/more mould appearing again.

phill99

Brallaqueen wrote: »

Condensation normally happens around window sills, behind furniture and even inside it.

Rubbish.

Condensation will occur when there is a significant difference between the temperature of the surface and the temperature and humiity of the adjacent air. Therefore it can form on any surface. TThe pics are consistent with ccondensation. Damp caused by water penetration is light brown in colour and will show evidence of staining.

Additionally, the vast majority of houses in the UK are built with cavity walls. Any moisture fronm say a gutter will only bridge the outer leaf and then run down the cavity, not across it onto the inner leaf.

lynzpower

ceridwen wrote: »

Will be following this with interest - as I have a similar problem and suspect that its condensation - though, in my case, its on the lower part of an outside wall.

Condensation by its very nature cannot appear on an outside wall.

As others have said what we know as condensation is when air ( with its moisture) hits a cold surface. this is aka Cold Bridging.

Therefore the water in the air turns from vapour to liquid when it hits that colder surface. We are used to seeing this on windows, you can feel in these cases that the glass is cold.

Condensation cannot happen the other way around ( ie outside air trying and failing to get into a building and depositing on an exterior wall as far as I understand it.

I would be more likely to be investigating a rising damp potential, split or broken waste pipes contributing to excess waste water collecting or other penetrating damp from broken guttering and so forth.

Anne3333

I would agree with Phill99, the photographs are far more consistent with condensation. Wipe down with a mould/mildew cleaner and increase ventilation.

bradleigh1977

its mould from condensation, i see this all the time. if its a bathroom, get a fan fitted, if you have one, then open the windows during the day, if you can.

teneighty

Just to throw a spanner in the works here's my opinion.

Yes it looks like condensation as other have said....BUT...there could be an underlying building defect which is aggrevating it.

It looks like the condensation is forming in a horizontal band only along the top of the wall and you said on the windows. That would suggest to me that something is happening along the top of the wall making it colder than the rest of the wall. This could be the cavity wall insulation has settled in the cavity leaving a gap at the top; the sarking felt in the eaves has perished allowing the top of the wall to get damp and therefore colder; leaking gutter. The choices are endless.

It's not something you are likely to get a direct accurate reply to, especially from a photo. In the meantime tackle the black mould with diluted bleach and follow the steps to reduce condensation and continue to monitor for any signs of penetrating damp.

ed110220

Brallaqueen wrote: »

I would not think it is caused by condensation. Condensation normally happens around window sills, behind furniture and even inside it. Any mould that appears that high up and away from large furniture would make me think leak from upstairs, gutter problems or rain getting thorugh the brickwork.

Not in my experience - I've had condensation causing mould problems on ceilings, high up on walls, low down on walls etc.

It always forms on the coldest surfaces, so usually on exterior walls and is worst in old houses that were built before cavity wall construction was introduced ie Edwardian, Victorian and before.

If it's condensation it will be most obvious in cold weather (not necessarily wet weather) so it will be worst in winter. Check to see whether little droplets of condensation form in these conditions, droplets like dew.

I would say it does not appear to be penetrating damp from the outside, as that tends to leave a distinctive brown stain.

phill99

lynzpower wrote: »

I would be more likely to be investigating a rising damp potential, split or broken waste pipes contributing to excess waste water collecting or other penetrating damp from broken guttering and so forth.

More rubbish.

Rising damp will only travel about 3 - 4 feet up a wall from the point of ground moisture. The capillary action sucks the moisture up the wall and gravity pushes it down. There is no way that this is rising damp.

lynzpower

phill99 wrote: »

More rubbish.

Rising damp will only travel about 3 - 4 feet up a wall from the point of ground moisture. The capillary action sucks the moisture up the wall and gravity pushes it down. There is no way that this is rising damp.

Ceridwen said she had condensation on the lower part of a exterior wall. Ceridwen didnt say how many feet up the wet area is : I assumed lower part was a couple of feet.

I know you dont get rising damp on a roof fhs