Is That Really Mould? Here’s How to Deal with the Fungi in Your Garage

Found mould in your garage? You’re not alone. Garages easily become damp, breeding grounds for fungus and you can likely guess why.

Even so, do not fret. Let’s tackle the problem and reclaim your space.

Is it normal to have mould in the garage?

It’s actually quite common and you will learn why in just a sec’. Since you’re reading this, you’ve likely already stumbled upon one of these mould types.

First, there’s the notorious white mould in the garage. It tends to pop up on walls, ceilings, and even on those boxes or old clothes you’ve stashed away. Then there’s black mould, which is a bit more sinister.

It’s more common to see black mould in your bathroom, but when it does show up in the garage, it’s usually a sign of a serious moisture issue. This type can be particularly worrisome because of the potential health risks it carries.

You might also encounter green mould or even blue mould in your garage. These varieties tend to grow on organic materials like wood, drywall, or even concrete surfaces that have accumulated dust and debris.

You could also see mould species like Aspergillus or Cladosporium cropping up. Although these might not always be as visually dramatic or immediately concerning as black mould, they can still pose health risks—especially for individuals with allergies or respiratory conditions.

In both cases, the appearance of these mould types isn’t random. It’s actually because of these reasons:

How long does it take for mould to grow in a garage?

With the right conditions, expect mould to start growing in your garage in as little as 24 to 48 hours. Even if you don’t see it right away, those microscopic mould spores are constantly in the air. When they land on a damp surface, they will set up camp almost immediately.

While you might not notice any visible signs at first, the spores are multiplying. By the time you spot those patches of growth, they’ve already had a head start. A few days of high humidity can be all it takes for mould to transition from an invisible threat to a visible problem.

How to detect mould growth?

Keep your eyes and nose open for these signs.

1. Look for visible clues. Mould often shows up as discolouration on surfaces. You might notice patches of mould in the garage ceiling, on the garage floor, or even creeping along the garage wall. Sometimes, it makes an appearance on the garage door or in the corner of the garage, where moisture tends to collect.
2. Trust your nose. Mould usually brings along a musty odour that’s hard to miss. If your garage, or that wall in the bedroom above the garage, starts to smell damp and earthy, it might be a sign that mould is lurking nearby.
3. Check the usual areas. Besides the obvious surfaces like the floor and walls, pay attention to hidden spots such as behind stored items or even within wall cavities. Mould in garage insulation is another common issue. Insulation can trap moisture and create the perfect environment for mould to settle.
4. Conduct a thorough inspection. Move your stored boxes and check behind them. Afterwards, inspect wall cavities and less accessible spots for dampness or mould growth. A flashlight and a keen eye can go a long way in spotting early signs of mould in garage insulation or that quiet corner of the garage.

Can mould in the garage make you sick?

If you’ve ever wondered, if that mould can affect you in any way, the short answer is yes. Mould releases tiny airborne spores. These can irritate your lungs, eyes, and skin. Breathing in the spores, especially in the long run, can lead to allergies as well as more serious respiratory issues. Black mould in the garage can even give you…

You say “It’s just the garage, how bad can it be?”, but mould doesn’t stay put. If your garage shares walls with your home, those spores can easily travel through cracks, vents, or even on your clothes. Garage mould can spread to other rooms, including your living spaces and attic.

How do I stop the mould growing in my garage?

Keep in mind that mould spores spread easily. Some types—like black mould on cement walls—can be harmful if inhaled. So, safety first!

What you’ll need to clean garage mould:

When you have all that, it’s time to learn how to get rid of mould in the garage:

1. Open up the space – Ventilation is key. Open the garage door and any windows to get fresh air moving. This will prevent mould on your window seals as well;
2. Spray the affected areas – Use vinegar for light mould or a stronger cleaner like bleach or store-bought mould remover for stubborn spots. Let it sit for about 10-15 minutes;
3. Scrub gently – Use a brush to work the cleaner into the mouldy surface, then wipe away any residue;
4. Dry the area completely – Leaving moisture behind will only invite the mould back.
5. Check for leaks in the roof, walls, or around the garage door. Even a small drip can lead to constant dampness. Contact a specialist who can help with the location and repairs if necessary.
6. Improve ventilation. Garages trap humidity. If you’re wondering how to stop things from getting damp in the garage, adding vents, a dehumidifier, or even just cracking a window can help.
7. Limit the moisture inside the garage. Parking a wet car inside without airflow or storing damp boxes, clothes, or furniture can create a mould-friendly environment. You might even get mould in your car.

Got black mould on cement walls? You may need a stronger cleaner and possibly a professional if it keeps returning despite your efforts.

Ways to maintain your garage mould-free

Once you manage to get rid of the fungus, you need to know how to prevent mould in the garage from reappearing.