Cape Town’s winter is almost done, which means the worst rainfall should be behind us, too. Unfortunately, the damage it did to your property won’t disappear with the storm clouds.
There’s nothing like the rainy season in the Mother City to test how waterproof a building truly is. At the same time, winter can worsen indoor condensation, as warm air meets cold walls, panes, and ceilings, while windows and doors tend to stay shut.
If you've walked into a room lately and caught that unmistakable musty smell or saw a dark “shadow” on a wall or ceiling, you're not imagining things. You just fit the “mould” of a typical Cape Town property owner dealing with untreated water damage after a wet winter.
Between the humidity, poor ventilation, and the volume of rain we've had, conditions have been close to perfect for mould to take hold. The good news is that this pesky fungus is manageable, provided you deal with it properly and address the root cause rather than just wishing it away with some paint and prayer.
Here's what you need to know about tackling mould in Cape Town’s post-rainy season.
Why should mould be treated?
Why should mould be treated?
Apart from being an aesthetic issue, mould can spread if left unchecked. This causes damage to paint, plaster, and other building materials.
Furthermore, mould contributes to poor indoor air quality. The World Health Organization’s guidance on dampness and mould links damp indoor environments with increased respiratory symptoms, allergies and asthma.
How do I know if there’s mould in my property?
How do I know if there’s mould in my property?
Mould spores are naturally found almost everywhere, but they only begin to grow when they come to rest on an organic surface (think dust, wallpaper glue, wood, drywall) that has sufficient moisture – either from condensation or untreated water ingress.
Look out for:
- Black, green, grey, or white patches on walls, ceilings, grout, or around windows
- Bubbling or peeling paint, discolouration or damp spots nearby the suspected area
- A musty smell
If a mark keeps returning after being cleaned, there is a good chance moisture is still present, and the mould is only the visible part of the problem.
First, find out where the moisture is coming from
First, find out where the moisture is coming from
Mould needs dampness to grow. So, the main task is not just to remove the ugly spots you see, but to find out why the area is damp in the first place.
Poor ventilation and high condensation are the first culprits to exclude when dealing with mould.
Water ingress can also lead to mould growth over time if left unresolved, especially behind skirting, under flooring, in wall cavities, or on ceiling boards. Common causes of water intrusion after a wet Cape Town winter include:
- Leaking roofs
- Cracked exterior walls and coatings
- Failed waterproofing
- Blocked or damaged gutters or downpipes
- Damaged flashing
- Leaking pipes
- Loosed sealants
- Areas where water collects
Damp can also appear around balconies, parapets, window frames, and flat roofs where water sneaks in through small gaps.
Keep in mind that the source of a leak is not always right behind the mould. You should check more than just the room where you first noticed it. Water can move through a building before you see it indoors, which can make damp problems hard to find.
Don’t just wipe and repaint
Don’t just wipe and repaint
Condensation should be reduced, ventilation improved, and the source of any water ingress repaired before restoring the damaged finish. Wait for everything to dry properly before taking further action.
For a small patch caused by condensation, cleaning the affected surface and improving ventilation may help.
Recurring mould, on the other hand, is a whole different animal. If moisture has soaked into plaster, ceilings, or other building materials, cleaning the surface will not solve it. Painting too soon can also cause blistering or flaking and yet another crop of mould. Your wall should not need a seasonal repainting subscription.
Fix the waterproofing before fixing the finish
Fix the waterproofing before fixing the finish
Different causes of water ingress require different waterproofing solutions.
Depending on the property, repairs could include sealing cracks, repairing roof details, upgrading waterproofing membranes or treating problem areas on exterior walls, balconies and flat roofs.
Once the leak has been stopped and the affected surface is properly dry, damaged paint and waterproof coatings can be prepared and restored correctly.
Prevent mould from returning next winter
Prevent mould from returning next winter
Good ventilation can help reduce indoor condensation, but it cannot compensate for a leaking building.
Keep your gutters clear, fix cracks early, and check waterproofed areas often, especially before Cape Town’s winter rains. If mould keeps coming back in the same spot, see it as a warning sign, not just a decorating issue.
Address the cause now, and next winter’s rain can stay where it belongs: outside.
Need help with mould marks?
Need help with mould marks?
If winter's persistent dampness has left an unwanted souvenir on your walls or ceilings, Coastal Painting and Waterproofing can help identify the source of the moisture, professionally apply the right waterproofing solution for your property, and finish it off with a new coat of quality paint.
Let's talk about getting your property waterproofed, healthy, and good-looking again.
