How to protect your home from winter paint damage — the South African guide
Winter does not announce itself before it starts doing damage. By the time you notice the peeling paint, the damp patch on the interior wall, or the white powder blooming across your painted walls or brickwork, the problem has usually been building for weeks or months. The good news is that most winter paint damage is preventable — if you know what to look for and act before the rains settle in.
This guide covers what winter actually does to your home’s painted surfaces, what to check before the season takes hold, and which products address each problem correctly.
What South African Winters Do to Exterior Paint
South African winters are not uniform. In the Western Cape, they bring sustained rainfall and damp. On the Highveld, the cold is dry but the temperature swings between day and night are severe. Along the coast, salt air compounds whatever moisture is already present. What all of these conditions share is that they stress painted surfaces in ways that accelerate existing weaknesses.
Hairline cracks in plaster and render — easy to overlook in dry months — become water entry points once rain arrives. Moisture gets into the substrate, the freeze-thaw cycle works on the crack, and by spring you have a significantly larger repair on your hands. Peeling or flaking coatings that seemed cosmetic in summer are now failing adhesion that allows water behind the film. Efflorescence — the white, crystals that appear on bricks and or plaster — is a visible sign that moisture is already moving through the substrate.
None of these problems are solved by painting over them. They require the correct diagnosis and the correct product.
The Five-Point Winter Check
Before the first significant rainfall, work through these five checks on your exterior:
Cracks in plaster or render: Run your hand along exterior walls and look carefully at corners, window and door surrounds, and any repaired areas. Hairline cracks need to be opened up at least 5mm, washed with Prominent Fungal Wash, then primed with Prominent Damp Cure and filled with a flexible filler like Prominent Ready Mix Crack Filler, allowed to cure fully, and then primed again before any topcoat is applied.
Windowsills and frames: Timber frames swell, split, and allow water ingress when the coating breaks down. Check for peeling paint, splitting timber, and any gaps between the frame and the surrounding wall. These need attention before winter, not after.
Parapets and flat roof junctions: These are the highest-risk areas for water penetration on any building. Check for cracks, ponding, and any areas where the waterproofing membrane has lifted or separated from the wall.
Efflorescence on bricks or plaster: If you can see white deposits, moisture is already present in the substrate. Painting over efflorescence without treating the source will cause the new coating to fail within months. The source of the moisture must be identified and resolved first.
Downpipes and drainage: Blocked or damaged downpipes direct water onto walls and into foundations. Check that they are clear, intact, and directing water away from the building.
Choosing the Right Product for the Problem
This is where most DIY projects go wrong — not in the effort, but in the product selection. Different problems require different solutions, and using the wrong product does not just fail to fix the issue; it often makes it worse.
For active water penetration through exterior walls, a flexible waterproofing membrane is required — not a standard exterior paint. Prominent Paints Neuklad Neuklad is a flexible exterior coating designed for South African conditions, providing a waterproof barrier on masonry and cement plaster surfaces while accommodating the thermal movement that causes cracks to develop.
For efflorescence and alkali-related problems on new or repaired plaster, the correct starting point is an alkali-resistant primer before any topcoat is applied. Prominent Paints Neuklad Alkali Resistant Sealer is formulated specifically for this — it seals the surface, neutralises alkalinity, and provides the adhesion base that your topcoat needs to bond correctly and last.
For general exterior repainting where the surface is sound but the coating is aged, a quality exterior topcoat applied over a correctly primed surface is appropriate. The Prominent Paints Neuklad range provides the UV resistance and durability that South African exterior conditions demand.
The Step Most Homeowners Skip
Priming. It is almost always the step that gets left out in the interest of saving time or money, and it is almost always the reason the topcoat fails prematurely.
On new plaster, repaired areas, or any surface where the existing coating has been removed or of the current paint coating is chalky, a primer is not optional — it is the foundation that makes everything applied on top of it work correctly. Paint applied directly to bare or unprimed surfaces bonds poorly, absorbs unevenly, and wears through significantly faster than paint applied over a properly primed substrate. Prominent Paints Neuklad Alkali Resistant Sealer is available in 5L and 20L at your nearest branch.
Frequently Asked Questions
Can I paint in winter in South Africa?
Yes, but conditions matter. Most exterior paints require surface temperatures above 10°C and relative humidity below 85% for correct film formation. On the Highveld, cold dry winters are often suitable for exterior painting during the warmer parts of the day. In the Western Cape, sustained rainfall and high humidity make exterior painting more difficult and the results less reliable. Always check the product data sheet for the specific application conditions required.
How long does waterproofing take to dry before rain?
This depends on the product. Most acrylic waterproofing systems require a minimum of 6 hours of dry weather after application before they can handle light rain, and 7-8 days for full cure. Always check the product data sheet and plan your application around the weather forecast. Applying waterproofing with rain expected within a few hours is a common and avoidable mistake.
What causes white powder on my exterior walls?
This is efflorescence — water-soluble salts that are carried to the surface as moisture moves through masonry or plaster and then evaporates. It is a reliable indicator that moisture is present in the substrate. Brushing it off and painting over it will not solve the problem. The source of the moisture needs to be identified and addressed, the surface needs to be cleaned and allowed to dry, and an appropriate primer applied before any topcoat.
What is the best product for a damp interior wall?
The answer depends on the source of the damp. Paint is never the solution to an active moisture problem — finding and fixing the source is always the first step. Once the source has been resolved and the surface has dried out fully, an alkali-resistant primer such as Prominent Paints Neuklad Alkali Resistant Sealer or Damp Cure should be applied before any interior topcoat. For persistent damp issues, speak to the technical team at Prominent Paints before selecting a product.
Do I need to prime before painting over an existing coat?
If the existing coat is in good condition — clean, sound, and dry — 2 full coats of repaint over a lightly sanded surface is usually acceptable. If the surface has been patched, repaired, or stripped back to bare plaster in any areas, those areas must be primed before the topcoat goes on. Inconsistent priming leads to visible patches and uneven sheen in the finished coat. When in doubt, prime the full surface for a consistent result.
Find your nearest Prominent Paints store at www.prominentpaints.co.za, or speak to our team in branch for advice on the right product for your specific surface and situation.