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How to Prevent Mould Growth

Mould Growth Behind Basement Walls
Mould Growth Hidden Behind Basement Walls, Covering the Entire Basement

Mould, a word that makes most of our stomachs turn. Mould can be a good thing under certain circumstances, it's used in penicillin and has various other uses. When it grows in our homes and living spaces it becomes a problem.

Why is mould a problem?

Mould spreads quickly and easily once it forms and cannot be removed completely. Often times it permanently damages whatever it grows on and you either have to remove and replace the item, do demolition or apply a sealant paint to contain the issue. When it grows undetected in your home, it can become a major issue leading to health risks and issues; especially in those with immune compromised systems, the elderly and young. It can lead to asthma attacks, allergy-like reactions among many other issues. Mould doesn’t simply grow in the basement or shower, it can form on food, carpets, paper, drywall and many other places, places you won't always see. It’s a common issue we find when opening up a wall or removing items from a building.

Here are ways to defeat the mould problem before it begins.

1. Identify Problem Areas in Your Building or Home

The first step to any situation is being prepared, you’re going to want to walk through your home or building and look for problem areas. Areas such as your basement, bathroom, attic, crawl spaces. Areas where water and dampness are common issues.

Look for:

  • Water stains

  • Leaks

  • Condensation on windows

  • Higher than normal humidity

2. Monitor Room Humidity

We’ve all seen it before, window condensation. This is a common issue in Canada where its cold outside and warm inside. If you have this issue, chances are there is too much humidity in your home or building. Humidity monitors are an inexpensive tool to help you figure out when the humidity in the building is too high. Humidity should be between 40-60% higher and you risk mould and other issues, too low and you risk a sore scratchy throat and a brittle cracking building.

Condensation on a window causing mould
Pretty Right?... Unfortunately No! This is a great example of there being too much moisture in your building.

This window picture above is now a mould growing machine ready to take over the window sills and spread. Try a humidifier and fan.

Photo Courtesy of Robyn Jade Photography, Winnipeg

3. Control Moisture

The easiest and quickest way to control humidity in your building is nature. Open a window, get some air flowing through. Install a fan or run your buildings heating or a/c. Your next best bet is to buy a dehumidifier; these come in a variety of shapes and sizes. They even have a system that runs with your furnace system. If your humidity is too low, a humidifier would be a great investment.

4. Repair Leaks Throughout the Building

Leak Repair for Mould Prevention

Leaks are a quick way for mould to grow. Finding and quickly fixing leaks will save future issues, damages and disasters. Check for leaks in your buildings pipes, gutters, roofs, Hvac units, washer, drains and foundations.

5. Monitor and Improve Ventilation


With our warm Canadian summers and cool winters, we typically have air movement 24/7. However sometimes that’s not enough. Make sure each area of your home is getting adequate ventilation. Some common areas that lack ventilation are bathrooms, crawl spaces, attics and basements. Install ventilation fans in your attic, crawl spaces and bathrooms if necessary.

6. Dry Items Before Storing

Before storing things long-term, make sure they are dry and not leaking. Check these areas frequently to make sure there are no accidents or arising concerns.

7. Clean Frequently

Clean your building frequently to make sure you catch problems before they start. Applying a disinfectant can help ensure mould doesn’t have a chance to grow. A frequent cleaning routine is a great practice to keep your building mould free.

Clean, Disinfect for mould prevention

8. Dry Up Damp or Wet Spots Immediately

If you notice a leak, damp spot or wet spot. Immediately clean up the mess. Ensure you remove as much moisture as you can with a wet vacuum, a towel or cloth and place a fan on the area for a faster drying time. In major cases it may be necessary to bring in specialized fans or dehumidifiers. Better yet, a local water damage restoration technician can help with the process; larger disasters may require insurance claims.

9. Replace Caulking

Showers and bathrooms are a common place for mould to grow. Caulking often is one of the first places you’ll find mould. Old caulking can crack and break away as well, allowing water to seep into the cracks and cause water issues behind the caulking, leading to further issues. Remove and replace the caulking as necessary

10. Use Mould Resistant Products During Construction

If you’re building a new home or renovating an existing one, try switching to mould resistant products where possible. They make mould resistant drywall and sheetrock for walls; they also have mould inhibiting paints. If mould resistant options aren’t possible, stick to other solutions or choose products that are easy to clean and maintain.

11. Direct Water Away From Your Home

Water sitting beside your home can cause leaks into the basement and major damage leading to mould or a disaster requiring remediation. Ensure the ground around your home drains away from the house, any spots with sitting water after a snow thaw or rain need to be re-graded to drain properly. A landscape professional can help with these outdoor issues.


Mould can be an unsightly and gross issue, taking these steps to ensure mould growth is stopped before it begins is the best way to help keep your home or building safe and mould free.

If you have any questions about mould prevention, feel free to ask your question below. Be sure to subscribe for more information, tips and help!

Q: Have you ever experienced a major mould problem? What steps did you take to ensure it doesn’t happen again? | Comment Below

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Noted Sources: IICRC Training, Industry Professional

Mould, Mould Prevention, Mold, Mould Remediation, Mould Removal Services, Mould Removal Company



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