There is no practical way to eliminate all mould spores within an indoor environment. This can be a problem since mould does not only stain and discolour surfaces – it can consume a property’s food sources. When these food sources are building materials, the integrity of the structure might be compromised, leading to costly repairs.

In addition to building damage, mould can affect tenants’ well-being. There is no way to know exactly how a person will react to mould; a normally healthy person may appear unaffected in a mould-infested building, while another may become ill.

So, what is a property manager to do?

To prevent a problematic and unhealthy situation, building management needs to understand what conditions are necessary for mould growth so it can ultimately control it.

Controlling mould growth
Mould requires three elements to grow: moisture, heat and a food source. Food sources for mould range from simple sugars and starches to complex carbon-containing substances. This includes wallpaper paste, cellulose from paper, drywall, fabrics and wood. Because these elements are common in virtually every building environment, they are hard to control and, for the most part, not a surefire way of preventing growth.

Controlling heat is also not a practical way for a property manager to prevent mould growth, namely because mould loves the temperatures that building tenants enjoy.

This leaves the final element: moisture. If a property manager can control and monitor moisture within a building, it can prevent mould growth. While it may sound simple, it does require regular monitoring and checkups.

Mould prevention
Large properties have many parameters that must be considered, including: plumbing; roof membrane and drainage; building envelope, windows, doors and flashings; stack effect (movement of air in and out of buildings), heating system; moisture generating appliances; groundwater; and tenant use and living conditions.

Because the parameters are many and can vary from building to building, it is important for management to identify areas of concern within the property early on and act promptly to prevent mould growth. Many times, this can require an experienced mould consultant.

Testing for micro-organism growth and moisture mapping are integral to identifying a mould problem and preventing growth. Testing for micro-organism growth entails using a chemical soaked swab that is brushed against the suspected surface and then inserted into a meter, which shows the results. Moisture mapping involves trying to find out where the moisture is coming from in the building, so management can pinpoint problem areas before growth occurs.

The most important thing a property manager can do when it comes to mould prevention in a large property is to create a monthly inspection checklist, followed up with a monthly walk-through to look for both signs of moisture and mould.

The inspection checklist should include:

• Roof, roof drains and flashings;
• Boiler system;
• Plumbing fixtures and piping;
• Caulking and weatherstripping on doors and windows;
• Air conditioner condensate pan drains;
• Appliance exhaust fan filters;
• Wet spots on building surfaces, including ceiling tiles and carpets; and
• Standing water around exterior of building.

With a little prevention and immediate attention to a leak or flood, building management can reduce the opportunity for mould to grow.

James A. Thomas is founder of Mouldoff Inc. and the general manager of Mouldoff Hamilton. Having spent 35 years in the restoration industry, James has experience inspecting and scoping building environs for indoor environmental concerns, and coordinating full remediation and restoration procedures on all types of building structures.