When the glass is cold, and the kitchen is warm and humid – the windows instantly mist, that is, there is condensation. The same thing happens with the walls. There are two workarounds: 1. Increase the heat resistance of the walls so that they are not cooled below the dew point (or heat them, which is what happens in heating season). 2. Reduce the relative humidity to dew point temperature has been below the surface of the wall (with, in principle, to start). To reduce indoor humidity, above all, to organize a conclusion moist air in the exhaust hole apartment. Here we should recall the law of conservation of matter: that somewhere in the air "stretched", it must somewhere "sucked." That is, you should immediately think about the influx of fresh air.
In most cases, the ventilation in the house (apartment) by means of vents: open – fresh, shut – heat. However, the ventilator is still no ventilation, twice a day to open – not enough (unless it is to keep it constantly open, but it is not always appropriate, for example, the child). So the question arises of ventilation. In fact, it is best to approach the problem comprehensively. Slightly warm the inside wall (the temperature rises to few degrees), slightly lower humidity by ventilation (thereby lowering the dew point even a few degrees). As soon as the temperature of the walls was above the dew point (directly dependent on relative humidity air) – condensate as had happened and therefore there is no threat of mold and mildew. Weaknesses – a bathroom and communication Fungus loves to settle in the bathroom and toilet, where there are a variety of sources moisture. For example, a constantly dripping faucet or toilet already create enough moisture, paving the way for intensive growth of mold and mildew. Therefore it is necessary to eliminate all leaks as they occur, and keep plumbing in good condition.