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There's Black Mould on My Walls - HELP!

If you’ve discovered black mould on the wall, there’s definitely cause for concern, but no need to panic. First, it’s important to identify the nature of the substance. And if it’s actually mold, then it’s time to call in a professional. Sure there are various DIY options available at the local home-centre, but mold is not something to fiddle with – it requires safe, proper removal and disposal. The fact is, mold can grow in any part of the home where there are high levels of air moisture.

Finding black mould on the wall can be disconcerting

It’s not unusual to find mold on walls, ceilings, and even in floors. In areas of a home where air moisture is particularly high, mold can thrive quite well. This includes basements, showers, and windows, all of which accumulate moisture that provides an ideal environment for mold.

For the most part, household mold is not dangerous to humans. But it can cause allergic reactions that might seriously affect the elderly or the very young. In general, symptoms can range from sinus congestion, to respiratory issues, to eye irritation. Adverse reactions are less common.

Why you may be finding mold in areas of the house

Depending on where you find mold in the house, it can appear in various shapes and various colours (a mold expert can often determine the species even with a visual inspection). In terms of colour variations, a mold infiltration can be everything from black, to white, to green, to blue.

  • you’ll usually find mold on walls where indoor humidity is quite high
  • mold also grows on window frames where the condensation is high
  • exterior walls are common for mold (warm inside and cold outside)
  • pockets of steam from hot water will allow mold to thrive and grow
  • leaky plumbing pipes (inside a wall) are ideal for mould to develop

In general, whether it’s a basement or a washroom, areas that are poorly ventilated will allow for high levels of moisture – a perfect environment for mould to start developing and spreading.

DIY mold removal is possible for walls and concrete

Removing and disposing mold from carpeting, wallpaper, and even furniture, is the easy part – as long as care is taken. As for a basement wall (or concrete floor) there are commercial products available designed to clean and kill mold. In fact, bleach is considered one of the better cleaners.

With any DIY mould removal, hard scrubbing is the key – at least until any remnant of mold has disappeared. With difficult infiltrations, you may well need to let the cleaning solution sit and soak before scrubbing. For the most difficult situations, a more powerful cleaner may be needed.

With mould, regardless of the severity, caution must be taken. That means wearing rubber gloves and safety goggles to protect your eyes. It’s often recommended to wear a dust mask so that none of the mold (or spores) can be breathed in. It’s also important to work in a well-ventilated space.

DIY mold removal from drywall and/or painted walls

In kitchens and bathrooms, it’s not uncommon for mold to grow on drywall, painted walls, and under wallpaper. In the worst-case scenarios, like a plumbing leak, drywall can get soaked, and remain wet, allowing mold to grow and fully penetrate the drywall (complete removal needed).

Clearly, surface mold can be removed with a DIY method, but when a plaster wall or drywall has been totally compromised, it will need more professional attention. Removing mold spots with a good scrub is not to be compared with complete mold remediation (full repair or replacement).

The truth is, a mold infestation is better left to a professional. Beyond the health risks, a mold expert can assess an infestation accurately, and recommend an appropriate cleanup. This is most important with water damage or flooding, where "black mold" has been allowed to pervade.

For mold removal, a professional approach is best

If you’ve found black mould on the wall, there’s likely a good reason. And although preventive measures would have been valuable in avoiding any infiltration, proper cleanup is absolutely essential. Proper cleanup is a must in addressing potential health risks and preventing any future spread. While it’s true that many mold outbreaks can be managed with a so-called DIY approach, there’s more reason to be extra safe – and that means employing an experienced professional.

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What Our Clients Say


Janice Martin

I am going to be the owner of the house we wanted thanks to Matrix. I just wanted to personally thank you so much for putting a rush on the work and making this happen! I was so worried I was going to lose this house so thank you so much for saving it for me! I will recommend your services to anyone I come across that may need them!


Cameron Williamson

Thanks for the professional work. We were going to deal with the mold removal ourselves and realized it was a bad idea. Your crew really knows what they are doing. Our place is spotless – and they even gave us some good household tips. I have no problem in recommending Matrix.


Robert Lee

Thank you for coming to the rescue. I didn’t quite know how dangerous asbestos could be, but I knew it had to be removed completely and properly. Thanks for the professional touch – I feel much better now that the house is clean and safe. I hope I never have to use this service again.