Mould (or mold in the US) can be an insidious intruder into your home. In a moist environment, it can develop gradually, often undetected, but with harmful effects to your health. We spoke to Gil Naparstak, owner of Alberta Restoration Specialists, to learn what to be on the lookout for and what to do if you find mould in your home.

What is mould?

Mould is any fungus that grows on food or damp materials. It can be black, white or almost any colour. It often looks like a stain or smudge and it may smell musty. When it comes to spelling, Americans spell it mold, while Brits use mould. Most Canadians follow the British spelling, although mold is seen in some Canadian publications (similar to centre vs center, or colour vs color).

Where does it grow?
Mould can be hidden behind drywall

Mould can be hidden behind drywall

Mould can grow indoors on window sills, fabrics, carpets, furniture, cardboard boxes and wood framing as well as walls in moist rooms like kitchens, bathrooms, and laundry areas.

Mould needs moisture and a material it can live on. It then releases tiny ‘spores’ into the air which people inhale. Breathing in large amounts of these spores and the by-products they produce can negatively impact your health.

Aside from these health risks, mould can eventually rot wood and damage your home’s structural integrity. According to Gil Naparstak, “I know a homeowner who had a load-bearing wooden cross beam that was completely rotted by mould. He had to hire a Structural Engineer to jack up the building so it could be removed and replaced. Simply installing a new cross beam beside the mouldy, rotten one would have contaminated the new one.”

What causes mould?

There are several potential causes of mould:

  • Condensation on surfaces due to excessive humidity, lack of ventilation, or very cold temperatures
  • Steam or excess moisture in the air from baths, showers and cooking
  • Water leakage, possibly from a roof or plumbing leak, a cracked basement floor or foundation, or flooding

You’ll need to find the cause of the water or moisture problem and have that fixed first, then remove the mould and take steps to avoid future mould.


Mould is usually detected by sight or smell, but not all mould can be seen or smelled. It can be hidden inside walls, above ceiling tiles or in the attic. And you may not always detect that familiar musty smell. If you suspect mould, it’s best to hire a mould testing company who will send a certified Industrial Hygienist (IH) to test your home for mould levels at a cost of $300 to $500. Once the mould is located and identified, hire a separate mould removal company to determine the best method for remediation and prevention.  According to Gil Naparstak, “Be sure the testing is done by a separate company that’s independent from the removal company. It’s a conflict of interest for the same company to test for mould and then to remove it.”

Once remediated, test again 2 weeks later

Once re-mediated, test again 2 weeks later

A good testing company will use their sense of sight and smell, but also take swabs and submit them to a lab for testing. They may also do testing with an air quality machine that compares the mould spore count inside and outside the home. If the count is higher inside the home, you probably have a mould problem.  Two weeks after the mould has been removed, get it tested again to ensure it’s been eradicated.

What to do if you find mould? Removal & Prevention.

mold-and-mildewAccording to Gil Naparstak, owner of Alberta Restoration Specialists, “Homeowners should not remove mould since they may cause cross-contamination into other unaffected areas of their home. The mould remediation process is quite complex and poses health risks. It should be left to experts who understand the equipment, chemicals and safety precautions.”

If it’s contained to a very small area, you may attempt to remove it yourself, but beware of the risk of cross-contamination. Since mould spores are likely to be stirred up during the removal process, seal off the affected area from the rest of your home. Wear gloves, goggles, and proper breathing equipment. Carefully remove and throw out any mould-affected material and then scrub the area clean. Once clean, use a borate-based detergent to keep the mould from re-appearing.

For larger areas of mould you should definitely hire a mould removal professional. In fact, in some provinces you may be required by law to hire a certified professional.


Often the most costly step is not removing the mould but repairing the underlying moisture issues that caused it, to prevent its recurrence. There’s no way to prevent mould with 100% certainty, but you can reduce the likelihood of mould by:

  • Controlling humidity levels especially in summer, with air conditioning or a dehumidifier
  • Promptly fixing leaky roofs, windows, and pipes
  • Properly ventilating shower, laundry, and cooking areas outside the home, not into the attic
  • Avoid hanging laundry to dry indoors. Remove dryer lint after each use
  • Don’t over-water indoor plants and watch for signs of mould in the plants
  • Thoroughly cleaning and drying after a flood
To recap:

If you suspect mould, get it tested then hire a separate company to remove it and prevent recurrence, then retest a few weeks later to ensure it’s gone. When it’s done, please consider writing a review to share what you learned with fellow homeowners.


Posted by David Bounsall