Author: Lucinda Curran

As a building biologist, my primary role is to identify the possible cause of health complaints and then hunt out the hazards in a home. It is quickly evident when there are problems with indoor air and electromagnetic radiation. However mould and problems from water damage is far less obvious – except to a trained professional.

Many people don’t realise that materials that remain wet for more than 24 hours begin to become problematic.

“Don’t worry about it, it’s only water!” Something we all have said… and then left the spill to dry out naturally.

Although this is a common behaviour, it is something that needs changing.

When something becomes water damaged from clean water, this is classified as Category 1. However, left wet for more than 48 hours, it progresses to Category 2, “grey water,” and after 72 hours it is classified as Category 3, “black water.”

Black water contains pathogenic agents – that is, it poses serious health risks.

However, it does not need to become grey or black water to become problematic. Materials that are wet can support mould growth.

When you think about it, mould is everywhere. It is so useful in our environment for breaking things down. All it requires is food, enough moisture and off it goes.

However, we do not want mould in our homes. Mould is not only structurally damaging to our buildings but can be incredibly problematic for health – particularly in anyone who has been sensitised to it, or is already vulnerable.

The other thing to know is that mould may be present even when you can’t see or smell it.

Mould may be growing inside a wall cavity, behind a cabinet or even on a visible surface but it is not visible to the naked eye.

Mould can cause many health complaints and Dr Ritchie Shoemaker has coined the term “Chronic Inflammatory Response” to describe the chronic issues those who are sensitive to mould experience.

I have found that it can play to the role of a stressor, and hamper one’s ability to handle other toxicants and stressors.

Water Damage Examples

water damage

1. Under the Shower Recess

This photo shows what was happening “behind the scenes” when there was a leaking shower. The whole underside of the floors were covered in mould, despite the floors only being six months old.
TIP: Leaks need your prompt attention.

water damage 2

2. Fascia Under the Eaves

This photo shows what happened to the asbestos fascia boards when the gutters had been blocked for a long time.
Often, blocked gutters result in water flowing into the roof space.
TIP: Clean our your gutters regularly.

water damage 3

3. Swollen Cupboards

In this photo, you can see that the chipboard has swollen from water damage, and the melamine is lifting off.
Chipboard is like fast food for mould – because it is ground wood, it is like pre-digested food.
TIP: Clean up any spills quickly.

water damage 4

4. Peeling Wallpaper

This photo shows peeling wallpaper. This had occurred years prior to my audit and was the result of overflowing gutters and roof damage.
What may surprise you is that despite there being no mould visible, I took a mould sample from under the raised portion, and the lab results showed elevated levels of mould spores and hyphae.
TIP: Attend to any leaks quickly and dry anything that has become wet.


Your home is like your second skin. It needs to be strong and healthy to support you in being strong and healthy

If you have any concerns, please contact a qualified Building Biologist – you can find one close to you here.

Always look for the ASBB logo – the ASBB checks the qualifications of all Building Biologist.