Damp buildings & Aspergillus

Aspergillus in the home

It is now widely accepted (WHO guidelines) that damp homes are bad for the health of many people including asthmatics (particularly severe asthmatics) and other respiratory illnesses (e.g. COPD, ABPA, CPA), children and the elderly being particularly at risk.

There is good evidence that investment in making homes less hospitable to damp & mould growth has a direct effect on human health. This is no longer a subject that is seriously debated - damp is bad for health. Exactly what it is about damp that is bad for our health is still strongly disputed, but the presence of damp is not.

Many homes suffer from damp at one time or another. Some obviously via flooding but other forms of damp are less easy to see:

Leakage of rainwater (broken guttering)
Leaking plumbing (hidden pipes)
Leaking roof
Penetration of rain through walls

There are many more sources within an occupied house including:

We breathe out and sweat moisture
Cooking (put a lid on boiling pans)
Showering & bathing

All of these put water into the air of our homes which can settle and form condensation on any surface cold enough. In time this can cause enough damp to promote mould growth

We can limit the spread of water vapour by closing doors while showering, bathing or cooking. We can install moisture sensitive extractor fans in the source areas (kitchens, bathrooms).

Humidity should be between 30 - 60% depending on the time of year (30% during dry months, 60% in wet months). Opening windows or window vents will usually equalise the indoor humidity with that outside and that is usually sufficient to prevent problems with damp indoors.

Some older properties (e.g. those with outside walls that have no cavity preventing moisture passing through to the inside wall) can still have problems when the weather is cold. In these cases keep an eye out for growing moulds particularly in areas where there is little air circulation (e.g. behind cupboards or even in cupboards if they are built in and use the outside wall as the back of the cupboard). Remove any growing moulds using 10% bleach (Suggested guidelines here) or preferably an antifungal treatment. If you can increase ventilation further then do so. Seek professional advice to try to eliminate the damp.

NOTE: moulds are only one source of health hazards in a damp house, there are several others e.g. bacteria can also grow in a damp home and be breathed in. Eliminating the damp should reduce the sources of many health problems!

Health hazards from moulds

There are at least three potential causes for ill health for people with normal healthy immune systems after coming into contact with moulds: infection, allergy and toxicity.

Mould particles (spores and other debris) are readily released into the air on being disturbed and are easily breathed into the lungs and sinuses of anyone in the area. These particles can cause allergies or become established and grow in small areas such as sinuses - occasionally even in the lungs themselves (CPA, ABPA).

Many moulds can make toxins that have a range of effects in people and animals. There is a lot of discussion and litigation currently ongoing (particularly in the USA) around the possibility that in some mouldy buildings it is possible to ingest or breathe in sufficient fungal material to cause health problems. Suffice it to say that on current evidence it would have to be a very mouldy building with a LOT of airborne mould OR there are as yet undefined health problems that accumulate from long term exposure to mycotoxins at a level that is thought not to cause acute health problems. More...

Controversy aside, it is clear from our experience that a few points seem to be generally applicable:

No-one should live in a damp home – damp is bad. Damp is water constantly entering the building and there is no way you will be able to control the growth of fungi unless you can control (eliminate) the damp.
Microbes need water to grow. The main way all of our houses can stay healthy is to eliminate water seeping into materials that can support growth of fungi/other microbes. The best way to do this is to eliminate the source of water e.g. condensation not draining away properly, poor ventilation, showers that drain onto the floor instead of the shower tray, leaking plumbing, water retained in faulty air conditioning units and so on.
If there has been a temporary flood which has saturated a large area of a room, dry it out as quickly as possible and monitor it for fungal growth – green/white/black patches appearing is fungal growth. It might take days/weeks to appear. If it appears, remove it and the materials it grows on (best done by a professional wearing a HEPA-filtered face mask).
As some areas of mould growth are well concealed, before you spend lots of money looking for hidden bugs move out of the house for a few weeks to see if your health improves. If it does and then deteriorates when you re-enter the building, then there is clearly something there harming your health. If you are seriously ill, leave the house to improve your health rather than taking medications to stay in the house.
Tests to find out if a home has fungal material in it will always find lots of signs in dust, carpets, soft furnishings, etc. It is usually a waste of time and money doing this. The tests must look at how much people in the house are coming into contact with the fungus – it does little harm unless it is breathed in or eaten. There is also the consideration that if a carpet has just been vacuumed there will be far more fungi in the air than if the air had been still for some time as the action of brushing the carpet will release lots of spores into the air. You may notice a difference in your health at those times too.

There should also be a comparison done with air that is known to give no health problems to the inhabitant of the house being tested – quite often this could be a sample of the air outside. Then you will clearly be able to see by how much the air inside the house is different from the clean air and this will give you a much better idea if it is what is in the air that is causing the problem.