Summer Opens the Cracks, Winter Finds Them
This is the Blouberg mechanism, and it is a two-stage process that most people only ever notice the second half of.
Stage one, summer. The south-easter blows hard across an open, flat, sandy coastline from roughly November to April. It is a dry wind, so it puts no water into any building. What it carries is sand, and sand travelling at speed against a rendered or painted wall works exactly like fine abrasive paper.
Over seasons, that abrasion thins paint films and surface coatings, particularly on the exposed elevations and at corners and edges where the wind accelerates. Once the film is thin enough, it crazes. What you get is a network of hairline cracks in a wall surface that still looks broadly sound from a distance.
Stage two, winter. The north-wester arrives from May, off the open Atlantic, at 50 to 65kph. It drives rain horizontally straight into the same seaward walls that have spent the summer being sandblasted.
Horizontal rain at pressure does not need a big crack. Hairline crazing is enough, because the water is being pushed rather than falling. It enters the render, gets held against the masonry behind, and comes through as penetrating damp on the inside face.
The homeowner sees damp on an internal wall in July and looks for a leak. There is no leak. There is a wall coating that lost its integrity in December.
The practical consequence is that wall coatings here are a waterproofing item, not a decorating item, and they have a shorter life on the exposed elevations than the manufacturer general figure suggests.
Salt, Metal and Everything That Corrodes
Blouberg sits on an open beachfront, which means continuous salt deposition on every surface of every building.
Metal roofs are common here, and salt attacks them at every point where the protective coating is broken. Fixings and their washers go first, then cut edges, then laps. The sheeting itself is often still sound when the roof is leaking through a hundred fixing points.
Galvanic corrosion runs faster in salt air, so using a fixing that is not compatible with the sheeting means the screw corrodes while the sheet stays perfect.
Gutters, brackets and downpipes corrode at joints, bracket contact points and cut ends.
Balustrades, handrails, awnings and any exposed steel, all of which corrode at their fixings, and every fixing through a horizontal surface is a potential leak.
Concrete takes chloride the same way it does on the Atlantic Seaboard, so exposed slab edges, balcony soffits and parapets spall on older buildings.
Combine salt with the summer abrasion and the winter driving rain, and Blouberg is one of the harder environments in Cape Town to keep a building envelope intact.
Sand, Gutters and Flat Ground
A few things here are specific to the terrain rather than the sea.
Wind-blown sand fills gutters through summer, and unlike leaves it forms a dense silt that holds water against the metal permanently and does not blow out again. Gutters here need clearing before winter regardless of whether there are trees, which catches people out, because there often are not.
Sand gets into flat roof outlets and valleys, and a sanded-up outlet blocks completely rather than partially.
The ground is flat and sandy, which means surface water behaves differently to the slopes on the other side of the city. Drainage away from buildings matters, and downpipes discharging at the base of a wall saturate sandy ground that then holds water against the foundation.
Newer developments across Blouberg, Big Bay and Parklands bring their own pattern: contemporary flat and low-pitch roofs, parapets, large glazed elevations facing the sea and the view, and balconies over living space. All of that is more detail-dependent than a traditional pitched roof, in an environment that punishes detail failures fast.