1. Install insulation in roof & under floor
2. Eliminate sources of moisture (ie, leaky roof or pipes)
3. Increase ventilation (open doors/windows regularly for short periods of time, install extractor fans)
4. Maintain ambient temperature in winter to keep rooms dry & prevent excessive condensation
5. Don’t use un-flued gas heaters as they pump out moisture
6. Paint/varnish timber surfaces
7. Ventilate bathrooms & kitchens, duct clothes dryers to the outside
8. Use a squeegee to clean shower walls after each use
9. Don’t put clothes away damp & don’t dry them inside
10. Repot pot plants regularly – soil can get mouldy
11. Clean, vacuum & wipe the house regularly
12. Do a full spring clean once a year!
Mould: more than just an eyesore
Whether in homes or commercial properties, mould is something often encountered in New Zealand. But how does it affect your health, when does it indicate a leaky building, and what should you do about it? Prendos Building Surveyor Dirk Stahlhut tells us about the ugly side of mould.
New Zealand is mould heaven. Blessed with warm, moist conditions (particularly in the North), our country provides the perfect incubator in which microbial organisms can thrive. It’s no surprise then, that a recent survey showed over a third of New Zealand houses have mould in at least one room.
“Moulds comprise a great variety of species that can colonize and damage very diverse materials, indoors and out,” explains Dirk. “They require an organic food source and moisture to grow, so you’ll generally find them in poorly ventilated, often dark and damp places where cellulose rich materials, dust or some other ‘food source’ is present. However even in the most weathertight homes, mould can find its way into the corners of ceilings, backs of curtains, shower areas or leather items in wardrobes. This could be because of frequent showering, certain cooking methods or inadequate airing of rooms locking moisture into homes for long periods of time.”
Leaky buildings are particularly affected by mould, as their design or building faults allow the ingress of rainwater. Many leaky buildings also lack adequate wall ventilation, which means materials can’t dry out once wet – causing mould growth to move quickly.
Health effects of mould
Different types of mould affect our health differently, and every individual’s response varies. Every day we breathe in a huge range of fungal spores, none of which are harmful. It’s only when this exposure goes into overload and the mould is of a particular type that problems occur. “There are four main mould species that grow in leaky or damp buildings – Stachybotrys, Aspergillus/Penicillium, Cladosporium and Fusarium. The latter two are commonly found outdoors, while Stachybotrys is the black toxic fungus linked to leaky buildings and is the most worrying to occupant health.”
Stachybotrys has major health implications – particularly for the young, elderly and those with compromised immune systems. Heavy smokers, drinkers or those on a poor diet are also shown to be more at risk.
“Health implications include allergenic reactions or allergic asthma, inflammation such as acute bronchitis, as well as toxic effects, fever and respiratory problems. Basically you may feel sick or fluey, have a streaming nose or eyes, develop a rash or have problems breathing. In extreme cases infection can occur due to the growth of disease causing microorganisms in body tissues. Studies indicate that exposure of young children to excessive levels of moulds may contribute to later allergies.”
When does mould indicate a leaky building?
The definition of a leaky building is one that has design or building faults allowing the ingress of rainwater into the wall structure. Growth of microorganisms is usually confined to this area for many years, with no signs of fungal spores appearing in living/working areas. Sadly, detection of leaks is not easy, but there are some tell-tale signs from a mould perspective.
“Finding mould doesn’t immediately indicate a leaky building, but the presence of black Stachybotrys signals a prolonged leak as this species requires an extended saturation time. Other signs include obvious leaks around windows or doors, a distinctive musty smell, discolouration of carpets or walls (particularly in the corners of rooms) and symptoms such as headaches, breathing problems or itchy eyes.
If you’re concerned, it’s best to get a building surveyor to come and take a look. We can point out design faults, detect hidden leaks, and find the areas where mould may be growing. We’ll also take material and air samples to determine the type of mould and assess whether there’s a health risk.”
What to do if you find mould
It’s best to avoid touching or smelling mould, and to wash your hands if you have come into contact with it. If it’s just a small area and the damage is superficial you can remove it yourself wearing rubber gloves and a mask, washing the contaminated area with warm, soapy water and drying well. Don’t use bleach as it can bind with organic compounds to form chlorophenols – irritating your eyes and throat.
A large area of mould requires total removal of the affected materials – best carried out by a trained operator. The contaminated material must be removed in sealed plastic bags and care should be taken to prevent any dried fungal spores from becoming disturbed and contaminating the air.