General Points About Damp

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. See our article on prevention of damp for advice on finding a professional damp surveyor. 
  • 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 - in the UK ISSE are a good source of links to remediation professionals).
  • As some areas of mould growth are well concealed, before you spend lots of money looking for hidden fungi or bacteria 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 feel seriously ill, leave the house to improve your health rather than taking medications to stay in the house.
  • There is little the medical profession can do to enable someone who is feeling ill from the damp to remain in a damp, mouldy home without suffering gradually increasing symptoms. Some people will be able to live in such a home quite safely with few noticeable symptoms but some will become ill. It is often not obvious who will have problems (exceptions being asthmatics, those with allergies, those known to be sensitive to the effects of breathing in moulds). The best result is usually obtained by moving out of the damp home and remediating prior to return. Some find they cannot move back after remediation but reportedly most can.
  • If you can see moulds growing in areas of your home that should be dry at all times (i.e. not bathrooms or kitchens) then you have a damp problem. Tests to find out if a home has fungal material in it will always find lots of signs in dust, carpets, soft furnishings, etc., whether or not the home has a damp problem. Cheaper tests often involve the homeowner leaving plates of culture media at strategic points around the home. This is often a 'false economy' as little can be concluded other than there is mould in the air - and there always is. This kind of test tells you a little bit about what species are present (though that depends on which growth media is used) but little about how much is present.

    There are better tests - one such is the well established test designed by the Environmental Protection Agency (EPA) in the US who look in some detail at what fungal species are present and from that information are able to make quite accurate conclusions of how much damp there is in a property. The test is known as ERMI but sadly is not yet available for commerical use. There are also tests that involve sampling the air or settled dust (and now even one that analyses the DNA to be able to tell you the identification of nearly every organism in a sample of dust ) but all individual tests have limitations and an experienced inspector would use more than one to come to his conclusions. The report of a good inspector will tell you why he is doing a test or set of tests, what he has found out AND what he hasn't due to the limitations of his tests. In the UK ISSE are specialists who can advise appropriately.

    All in all for domestic use if there is visual evidence of the appearence of moulds in places where it shouldnt be, then there is adequate evidence that there are problems and usually no further testing is needed - start looking for the cause of the damp!

  • Mould does little harm unless it is breathed in or eaten. Spores can be released from simply walking on a contaminated floor, by draughts or other disturbance. There is also the consideration that if for example 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.
  • Remediation does work for most people but this is a skilled job that is often best left to experts (ISSE, RICS for advice).
  • We have noticed that many people who live in damp homes are in dispute with their landlord. Often the landlord claims that the tenant is responsible for the damp and in the UK that is partially true as some tenants refused to adequately ventilate their homes in winter, but often there are measures that the landlord can take too. We think a compromise needs to be reached and in the UK there is a housing ombusman service who can mediate these disputes.