Frequently Asked Questions About Mould

About Moulds:

Moulds can be found almost anywhere; they can grow on virtually any substance when moisture is present. Outdoors, many moulds live in the soil and play a key role in the breakdown of leaves, wood, and other plant debris. Without moulds we would all be struggling with large amounts of dead plant matter. Moulds break down plant materials by digesting them, using the plant material for food.

Moulds produce tiny spores to reproduce, just as plants produce seeds. Mould spores waft through the indoor and outdoor air continually. When mould spores land on a damp spot indoors, they may begin growing and digesting whatever they are growing on in order to survive. There are moulds that can grow on wood, paper, carpet, foods, even dynamite. When excessive moisture or water accumulates indoors, mould growth will often occur, particularly if the moisture problem remains undiscovered or unaddressed. There is no practical way to eliminate all mould and mould spores in the indoor environment; the way to control indoor mould growth is to control moisture.

All moulds can cause health problems such as asthma episodes in individuals with an allergic reaction to mould, but the effects of mould on the human body are not fully understood. The Center for Disease Control in the USA states, "The hazards presented by moulds that may contain mycotoxins should be considered the same as other common moulds which can grow in your house". Even people who seem to be immune to the effects of mould can become sensitized and start showing symptoms after repeat exposures.

1. How does mould grow?

Mould needs four things to Grow Indoors:

1. Spores - these are always present in our environment whether indoors or outdoors.  There is no such thing as a mould free environment.
2. Nutrients (food) - in the indoor environment these are normally the cellulose materials (paper, wood, cardboard, fabrics, dust, etc.)
3. Moisture - this is required to begin the decaying process of the cellulose material by the mould.
4. Time - growth typically begins between 24 hours and 10 days from the provision of the growing conditions.

Control Moisture:

There is no means of controlling the presence of spores, the presence of nutrients or the passage of time.  The only thing that can be controlled is the moisture.

Sources of Moisture:

1. Direct Water Penetration:  e.g. Leaks in the basement, roof, around doors and windows, ice damming in winter, penetrations in the building envelope, wet building materials
2. Flooding:  e.g. Plumbing leaks, accidental spillage, storm flooding, sewer backup
3. Condensation and humidity:  e.g. drying of the structure, construction heaters, lifestyle, lack of insulation, lack of ventilation, design issues.

2. Why is Mould such a big problem?

There are a number of reasons why mould contamination is becoming more common in our society.  One of the main reasons is that more research has been done into the Health Effects of moulds and more links have been found to such things as Asthma.  This has also prompted more media coverage and more people are aware of the dangers.  Another reason is that there has also been a change in the way that buildings are constructed.  Generally buildings are much more air tight today than they have ever been, insulation levels have been increased, but there is often little attention paid to the mechanical system and in particular to the supply of fresh air.  This means that it is difficult to control humidity levels and condensation and this small amount of moisture is often all that it takes for mould growth to start.  Once the growth begins, extreme colonization can occur very quickly if the conditions are optimized.  One other reason is that general quality of construction in a booming economy often produces an inferior product because time and profit are paramount.  Well designed, well built and well maintained buildings rarely have mould contamination problems.

3. Is mould more likely to be a problem in an older building vs. a new building?

There is no way to say which is better.  An older building that has been well maintained and has not had moisture issues should be relatively mould free but an older building that has been poorly maintained or has had moisture issues can have massive mould contamination.  In turn, newer buildings built well will be relatively mould free and will be less likely to have future mould issues, however not all newer buildings are designed or built well and thus they have the potential to have massive mould contamination problems.  The simple rule is look for a building, new or old, that is well built and well maintained.  Ensure that the ongoing general maintenance issues are regularly checked and repaired as needed.  Adopting a sensible and logical approach will greatly reduce the possibility of having a mould contamination issue in your building.