The worst trait of our summer arrived early this year. One minute Hong Kong was shivering - the next the annual mould home invasion was back. Mould and fungi, in their various forms, are nobody's friend: they look unsightly, and can quickly ruin your best clothing, leather goods and furnishings. They also contribute to poor indoor air quality, and are linked to asthma attacks and other respiratory and allergic conditions. If your mould problem seems worse this year, handyman Mark Fraser of CDI Hong Kong (aka manwithdrill.com) says that may be because of sudden temperature fluctuations. Fungal spores are almost always in the air but to develop into mould they need moisture or condensation, 'which Hong Kong has had plenty of lately', he says. Those who have lived in other hot, humid climates but haven't had to wage war on mould wonder why Hong Kong homes are predisposed to the yearly growth. Fraser says this could be because of building design and living habits. 'It could be that the construction of windows and vents in other places are different to Hong Kong, creating different temperatures inside the buildings,' he says. 'Perhaps people tend to use fans more often elsewhere.' In Japan, for example, an open-plan internal layout favouring screens, as opposed to solid walls, would create a more even temperature throughout. 'Also, the use of centralised air-conditioning systems may better regulate relative humidity levels,' he says. Fraser's tips for dealing with mould include using an air conditioner - ensuring the filters are cleaned regularly - and keeping windows closed. He says that if you don't close your windows in humid conditions the materials in your house will absorb moisture, regardless of the internal temperature. An ionising air purifier will remove spores of mould and dust in the early stages, he says. Relative humidity in your home should not exceed 55 per cent in the daytime, Fraser says. 'You can buy a digital humidity sensor if your air conditioner doesn't have a readout. This will indicate the correct figure in your home. If the reading is high, check your filters and coils are clean and look for leaks. 'Also check for any water leaks around air conditioners, under windows and sinks. Use exhaust fans in bathrooms and shower areas, and wipe wet areas dry after use.' Scrubbing is a fact of life where mould is present. Fraser says vinegar may help: the acetic acid reacts with the mould to inhibit growth. 'For non-severe cases household bleach diluted one-to-one can be washed over the surface using a sponge or cloth. If severe mould is present you should buy a chemical mould solution such as the Sandtex brand, and apply using a brush, but it's quite toxic so rubber gloves, eye protection and a suitable mask need to be worn.' After sufficient drying time, this process can be followed with the use of a good quality anti-mould paint such as Dulux Supreme or Nippon 5-in-1. Apply at least two coats. If you really feel defeated, you could call in the mould-busters. Phillip Fry lives in the Philippines but regularly packs his hi-tech kit to carry out home inspections in Hong Kong. Fry trained as a 'certified mould inspector and remediator' after identifying mould as the culprit in his own ill health. He has written five books on the subject and runs a website ( www.moldinspector.com ). Fry is not convinced Hong Kong's mould problem is any worse than in previous years, but feels that people are becoming more aware of the associated health risks. Most mould is hidden, he says, often inside air conditioners, which should be cleaned thoroughly at least every three months. Any place where water gets in - from, say, a leaky roof or dripping pipe - is a danger spot. Mould can grow on your wall paint, and be all but invisible as it gnaws away at your timber furniture. You mightn't realise it's been eating away at your bedhead or dresser until you pull it out to clean behind and find tell-tale signs on the wall. Leather is 'really delicious' for mould, he says, and poorly ventilated closets or organic clutter such as piles of newspapers are a fungi playground. On a typical home inspection (costing US$1,000 upwards), he starts by using a moisture meter to identify unseen water sources. He collects samples of visible mould spores, to be identified by a microbiologist. Interior wall cavities and the insides of air conditioners are probed and videoed using a fibre-optic camera. A hygrometer is used to measure humidity. Finally, he uses his sight and sense of smell. A written report and action plan will result, but Fry prefers to train the householder on the spot. Getting rid of mould is 'not rocket science', once you know what to do, he says. 'Most householders can do the job themselves, or hire a handyman.' 'The job' involves washing down walls and ceilings every few months, and keeping all furniture surfaces scrupulously clean. Fry says regular chlorine bleach 'doesn't work' on mould, recommending instead a wash made with boric acid (not sold in Hong Kong, but available online from moldmart.net). An effective dehumidifier is crucial to any mould combat plan. Fortress offers the following tips for choosing the right model: Size up your flat. A 300 square foot space needs a 16-litre dehumidifier. Check the location of the air outlet, as these vary. Japanese brands, with the air outlet at the back, should be kept 30cm away from a wall. European models can be put against the wall as the outlet is at the front. Look for special functions. Models with a timer can be set to reduce humidity to the required level, and then shut down to save energy use. Some of the newer air conditioners also come with an independent dehumidifier function, although these are less effective than dedicated machines. Fortress stocks two brands: Fortress model FCD08CXR6 and Hitachi model RA08HDF1HK.