mildew on the wall of a new house

[calvert]

My daughter has 2 year old terraced house. The party wall with her neighbour has mildew from the floor to about 1 foot in height. It returns everytime they clean it off. It is only on this one wall. Any ideas please?

 

[joe-90]

If it's on the ground floor then probably a leaky pipe.

 

[calvert]

I dont think there are any pipes in that area but I will check. The walls are dry-lined so surely a leak would show as a damp patch first

 

[^woody^]

You need to wash it with a proper fungicide, and then read up on condensation prevention

 

[JohnD]

does she dry her washing indoors?

is it a solid floor, or wooden?

 

[noseall]

New house?

Reoccurring mildew??

First ask and check the neighbours wall to see if they have a similar problem. There is something cooling that area of wall and i would not rule out a leak as Joey said.

 

[JohnD]

party wall, so the leak might be on the other side. Could be a pipe in or under the floor, could be a radiator, could be a sink, could be a washing machine, could be a fishtank, could be dripping from above, could be a CH pipe behind the plasterboard.

 

[^woody^]

If there was a leak and these are lined walls, then the plasterboard would probably be nice and soft by now

What is common with lined walls, even in new build, is a cold draught or hole behind the plasterboard which creates a cooler surface.

Primarily though, it would still be a condensation issue which needs addressing

 

[JohnD]

would it be worth cutting out a panel of the plasterboard to have a look behind?

 

[^woody^]

I would not do anything like that yet.

First should be to wash it down properly with fungicide, and then monitor it, and follow any condensation prevention advice - as it may well be a lifestyle cause

At the same time, just check for any possible leaks to rule them out

Only if the OP is satisfied that the cause is not due to lack of ventilation or damp washing in the corner or something, should they investigate behind the plasterboard

If they know anyone with an infra red thermometer then this can be useful to find a cold spot - but moisture will influence the reading

 

[calvert]

Many thanks for the replies. I've been round today to have a look for myself. They have the trickle vents open on the window but I doubt they do much. I reckon they definitely need more ventilation, open windows, but they are right on the pavement so I guess there is a security issue there. There is black mould in both front corners of the living room so I dont suppose its a leaky pipe. I am just surprised at a new house house suffering from this...surely mould has been regulated out of new-build along with everything else?

 

[wingcoax]

If it comes back after cleaning, you really need to contact he builders or the agency you/they bought through.

 

[JohnD]

If anyone drapes wet washing around the house or over radiators, it will always be damp.