The 4 most asked questions about mold

Molds are part of the fungus family. They’re omnipresent in the environment and multiply via the dispersion of their spores in the air. The air and surfaces of our environment (indoors and outdoors) are naturally filled with spores that are waiting for certain conditions to be met (moisture, temperature, organic matter, oxygen) to sprout (producing hyphae) and produce mycelium (grouping of hyphae that form patches or colonies, making mould visible on materials) that can in turn sporulate and recontaminate if the same conditions are met.

Does mould deteriorate materials?

Contrary to popular belief, mould and mildew don’t deteriorate materials. They generally present themselves as surface discoloration and mainly affect indoor air quality. Wood-decay fungus is the only kind of fungus that has the enzymes to alter and rot materials like wood. Nevertheless, it’s important to understand that the development of wood-decay fungus also requires a moisture source.

The first sign of an unresolved water problem is the appearance of mould, but the inevitable result is the growth of wood-decay fungus, and rot. To find out more about the damages caused by wood-decay fungus, click here

Where does mildew smell come from?

Odours associated with moisture (damp ground) are often noticeable in buildings. These smells aren’t really of dampness though, because water doesn’t smell like anything. They’re actually caused by the microbial volatile organic compounds (VOCm) that are created when mould, mildew and other bacteria are allowed to fester indoors. The odours are a kind of defence that is more or less specific to each kind of mould and/or bacteria. Microbial volatile organic compounds are powerful gases that can easily go through material. If you think you smell dampness, what you actually smell is a hidden fungal growth problem.

Are mould and mildew toxic?

Mould and mildew aren’t considered toxic, but rather allergens. It’s the secondary metabolites produced by certain kinds of mould called mycotoxins that can be toxic. Many mould species identified in damp buildings are known to produce one or more classes of mycotoxins, which is why people refer to them as “toxic mould.” Unlike spores, mycotoxins aren’t volatile and most cases of reported exposure come from ingesting them (when they deposit on food). They can adhere to dust particles and spread through the air attached to these dust particles or spores, making them easy to breathe in.

It’s important to remember that the mere presence of so-called toxic mould, which can produce mycotoxins, isn’t a definite indicator of the presence of mycotoxins. The production of mycotoxins depends on very specific, very damp environmental conditions. To this day, they remain difficult, and expensive, to identify.

Do I need an air quality test?

In most cases, the answer is no! An air quality analysis or other form of laboratory analysis isn’t usually necessary during the initial assessment. Even if you see mould, the air quality test might not reflect what you see. The fungal load (kind and/or quantity per m3) shouldn’t affect the proposed decontamination protocol. If you have visible mould, you should remediate the situation no matter how much of it is present.

However, air quality analysis can be useful in cases where:

Occupants may be allergic, immunocompromised or diagnosed with an illness related to mould exposure;

You can smell microbial volatile organic compounds but no traces of mould are present;

You think your ventilation system is contaminated;

A forensic or technical-legal diagnosis is required;

The quality of decontamination work has to be validated. In this case, the results of the analysis should be accompanied by a detailed inspection noting the quality of the work performed and the conclusions drawn from the interpretation of the results by the investigator.

In all cases, the objective of a sampling strategy is to confirm or deny the assumptions made by the investigator during the initial inspection. The extent and scope of the contamination is then determined by comparing indoor air quality in different areas of the building, and outdoors. Sampling results should show similarities in quality and quantity, otherwise the areas are considered to be contaminated, and have an abnormal fungal profile.

If you see mould, think something might be contaminated or have a laboratory report identifying a fungal contamination, contact us