Managing Mo(u)ld and Moisture

One of the biggest concerns I see as a home inspector involve air quality and mould. What exactly is mold and is it dangerous? The most important thing to know is that there is no such thing as “toxic mould” or “black mould”. Mould is a part of the fungi family, to which nobody knows how many species of fungi exist. The most common types of indoor molds are:

• Penicillium
• Stachybotrys
• Alternaria
• Cladosporium

The important thing to know is that like radon, mould spores are literally everywhere and cannot be eliminated. Knowing if mould growth can be considered toxic or dangerous requires the use of a laboratory test and this cannot be detected by a standard home inspection.

The main area of concern for the home inspector are:

1. Potential negative health effects.
2. Wood rot, drywall damage, overall structure damage.
3. Negative aesthetic effects, both to the eyes and nose.

So, what is a homeowner to think? This topic is a perfect example of why I am a systematic home inspector and not an “electrical” or “plumbing” or “structural” inspector as these systems are all interdependent in a home. While I could lull you to sleep with my many hours of research, the biggest takeaway is that moisture control is the key to mould control. Did I mention that moisture is the sworn enemy of the home inspector?

Here are some steps you can take to keep mould growth at bay:

• When water leaks or spills, act quickly to clean it up.
• Clean and repair roof gutters regularly.
• Make sure any drainage lines (such as from air conditioning or ventilation) are clear.
• Keep indoor relative humidity controlled, ideally between 30-50%. The bonus is that humidity control can also reduce energy use and increase comfort.
• Condensation on windows needs to be addressed immediately as this is a red flag for high humidity and poor air flow.
• Use kitchen and bathroom fans or open windows when necessary.
• Cover cold pipes with insulation.
• Monitor plumbing for potential leaks or drips.

Moulds are not generally dangerous but any signs of mould (such as black patches on the bathroom ceiling) should be handled as soon as possible. Generally, it is NOT a good idea to use biocides, chlorine, or other disinfectants as this will not eliminate the root cause, and dead mould can still cause respiratory problems. The best course of action is to prevent mould from taking foot by…. you guessed it…. moisture control. You may have noticed some similarities to this article and my first article on radon and that is no coincidence: the strategies for clean air, mould, asbestos, and radon mitigation are largely the same and can be summed up in three points: source control, improved ventilation, and air cleaners. 

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