A mould problem in the home is most often caused by a build-up of condensation. This occurs when moisture held in warm air (such as from showering or boiling kettle) meets cold surfaces, such as a glass window or a tiled wall. The warm air then condenses into excess moisture, which has nowhere to go. Modern homes have made this situation worse. Better standards of insulation, such as double glazing and draught proofing work brilliantly at keeping heat in, but also trap moisture in the same way.

If this happens regularly, the pooling excess moisture lingers in the same area, settling in regular places, such as on window frames and in the corners of baths, which can eventually become a mould infestation.

Whilst tasks such as showering and boiling kettles are an obvious source of condensation problems, another key day-to-day household task that is high on the list for creating excess moisture in the air is drying clothes. Overcrowding in a room or household can be a real issue too.

Of course, the cause of damp does not have to come from inside the property. Damaged guttering, broken roof tiles/flashing, damaged mortar in external walls or a leaky pipe hidden deep within a wall can be the cause a damp area inside the property. This is known as penetrating damp.

Finally, rising damp. Occurring on the ground floor or basement, this sort of damp happens when moisture is soaked up though a broken or absent damp proof course, into the bricks or concrete foundations of the property.

Impact

As well as being a risk to the tenant’s wellbeing, a damp problem will have a lasting impact on the property. Should internal walls be subject to ongoing moisture, it is likely that significant repair work will be required to get plasterwork back up to a good standard, and woodwork is likely to suffer, too.

How to fix the issue

Work out where the problem is coming from. There are some simple fixes you can try.

1. Install light-activated extractor fans in the bathroom and kitchen – these are the key areas that cause problems internally
2. Install a tumble dryer, this is to replace drying clothes inside
3. Explore vented windows – if windows are left unopened, bedrooms can be hotspots for condensation. Many windows now offer vented options allowing airflow whilst maintaining warmth and security
4. Consider installing air bricks if they are not in place already, and check that they have not been blocked up!
5. Request that large items of furniture (wardrobes etc) are not pushed flat to the wall. This encourages air flow around them and prevents build up behind them.

If you have a significant problem, you may need to look at ventilating the property, using dehumidifiers to draw water out of the fabric of the building. They must be left on continually and are not always very quiet.

If damp has come in from outside, contact your landlord who will check the maintenance of your roof, guttering, damp proof course and brick work.