Mould and Mildew

One of the many maintenance issues facing domestic strata type developments is the issue of mould and mildew within a building. The rain and cold weather over the last couple of months has seen a dramatic increase in calls for us to inspect mould in Strata properties.

I thought it may be worthwhile getting some information out there about the causes of mould, the ways of preventing it, and some tricks of the trade to remove it.

What is it?

Mould is a living organism, fungi that grows like a network. Generally speaking the mould we tend to see in a building thrives at temperatures from about 4 Degrees C where humidity is high.

A quick search of the internet can provide you with a wealth of information on the science relating to mould.

Where will it grow?

Mold in the home can usually be found in damp, dark or steam filled areas e.g. bathroom or kitchen, cluttered storage areas, recently flooded areas, basement areas, plumbing ducts, areas with poor ventilation and outdoors in humid environments.

What causes it?

Many things will cause it to grow, but generally speaking in the types of environments we are seeing it in recently on walls and ceilings. We have studied several cases and found that generally there is a common theme to these cases:

  1. Most commonly ground floor units that either have a southern aspect or are shaded by trees or surrounding buildings.
  2. Most Commonly on Brick or Concrete Surfaces that are either common or external walls.
  3. Warm air environments particularly where the occupants use a radiant type heater such as an Un – flued Gas Heater or Exposed Electrical Element.

Water leaks and roof leaks will also in cease the incident of mould. Have a professional like a plumber check the site to make sure there are no water leaks, failed membranes or roof problems. Check that the Plumber has a Moisture Meter and they know how to use it.

How does it grow?

In the most severe cases we have noted in our research that the mould starts to grow on a wall or ceiling that is generally cold to touch, most of the time it’s an external wall that is directly in contact with the ambient air outside. In most cases the affected wall is shaded, and gets very little natural warmth from the sun. When it rains or if there is excessive moisture in the air because of things like showers and cooking appliances, the damp or moist air is heated inside the building from things like room heaters and as that warm moist air comes into contact with the cold walls condensation begins to form. Quite often we have seen the condensation to the point of absolute saturation and the water literally runs down the walls and windows of the property. The condensation that remains on the surface becomes a breeding ground for the mould spores and in a very short space of time the mould can spread vast areas.

How can it be stopped?

The first thing that needs to happen is the moisture needs to be removed from the surface and the air, the best way to do it is ventilation. Ventilation can be as simple as opening doors and windows allowing cross ventilation or the area may require additional ventilation bricks and in some severe cases it may require fans and forced air movement. Mould does not survive very well in open well ventilated spaces.

Secondly you will need to try and get some natural light and warmth into the affected walls. Trimming trees, opening blinds will help. A property with a southerly aspect will be the worst affected by this particularly in winter when the sun is low in the sky.

Limit the use of artificial heating, Un – flued Gas Heaters, Radiant type electric heaters will heat the air in the room and increase the amount of warm air in the area. Obviously we need to keep warm, Reverse Cycle Air Conditioner ill help as they tend to remove the moisture from the air.

The weather will be on your side, as spring and summer approach and the weather warms up the spread of Mould will be easier to contain.

How do I get rid of it?

Not easy, As the Mould is an organism it has to be killed. Simply cleaning it will not stop it from growing back. Address the cause, and implement a strategy to stop the mould from growing then you can look to get rid of it permanently.

Special Mould killers do work, it takes considerable elbow grease but it will work if used in accordance with the manufacturer’s instructions. We have used a couple of products and we have had particular success killing the mould and spores with Selley’s Mould Killer and then sealing over with Zinisser B.I.N. Both products should be available at your local hardware store.

Like all maintenance and repair issues, every site is different. You should contact a professional. Seek advise, ask questions and if your not confident in that professional gat another opinion. It can be a very expensive process and without the right diagnosis or strategy it will cost much more than it should.

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