Condensation cure?

[dommy4]

hi we have victorian style ground floor converted flat that we have renovated. In the bedroom we have no ventilation and built in wardrobes on an exterior wall that covers an old fireplace.

We are pretty sure now we have condensation but there is a particulary damp and mouldy spot directly under the bay window that seems to be limited to that space and also mouldy clothes inside the w/robe. I have now opened up the fire place and using grills trying to vent the wardrobes.

Is it possible to drill a core hole to the outside via/into the wardrobe to help ventilate or is there a better cure?

Thanks.

 

[JohnD]

...In the bedroom we have no ventilation ...

Well, that explains why you are getting condensation.

You need to ventilate the room.

An air-brick on two sides of the room will allow cross-flow of air. Or trickle vents at windows. You can use a core drill to make neat holes in the wall much easier than hammer and chisel, and can buy plastic covers for them. If you have two vents you will not normally need extractor fans as you will get airflow. If they are not on opposite sides of the room then put one low and one high.

If you just extract from one side of the room you will be pulling in air from other parts of the home which may also be damp.

External air is more likely to be dry. Cold air holds less moisture than warm.

If the wardrobe is on an external wall it will be relatively cold inside thus the mosture n the air will tend to condense.

A bricked-up chimney will be damp unless it is ventilated top and bottom.

 

[^woody^]

External air in winter, can be over 90% humidity, so ventilating and letting cold damp air in, is not in itself the best thing to do.

The problem with the wardrobe is that it will offer a cold wall behind it for moisture to condense on. Even if you ventilate it, it will still happen.

You need to ventilate moist air - at source in the kitchen, bathroom and any drying clothes on radiators etc. You need to keep the house at a constant temperature - not roasting hot, but an even temperature and not keep letting the rooms get warm and cool. And you need to insulate cold surfaces - ie external walls to stop air condensing on them. You also need to mop up any condensation as soon as possible.

Its a fine balance, and you need to experiment.

You should also throw out the mouldy clothes, and either treat the wardrobe with a fungicidal wash, ot throw it out too. If you leave mould, it will just keep sporing.

 

[JohnD]

...External air in winter, can be over 90% humidity....

Yes, at its cold outdoor temperature. but when you bring it indoors and warm it, the same amount of moisture makes the relative humidity much lower.

(There's more water in hot "dry" air in the Sahara noon than in "wet" cold air in a Manchester fog)