Roofing in the Northern Cape

The arid-interior insulation target

SANS 10400-XA divides the country into six climate zones. The NHBRC's guide to the standard lists Upington and Kimberley in zone 6, arid interior, where a new roof assembly needs a minimum total R-value of 3.5, rated for heat flowing upwards. That's well above the 2.7 required in the sub-tropical coastal zone, and the heat-flow direction is the same as on the cold Highveld: the rule is aimed at keeping warmth in on those freezing winter nights.

Heat is likely to get worse. The provincial modelling quoted in the Namakwa plan projects average temperatures up 1.6°C over 2020 to 2050 under a medium-mitigation scenario, with about 12 more heat waves. If you're re-roofing, the ceiling space is open anyway, so it's the cheapest moment to bring the insulation up to the zone 6 figure. Our ceilings and insulation page explains the options.

• Ask the roofer or designer to confirm they're working to zone 6 and to show how their build-up reaches R3.5.
• A light-coloured roof covering reflects more of the summer sun; ask the supplier for the colour's solar reflectance if they publish it.
• Check that existing insulation hasn't been flattened or pushed aside by previous work in the roof space.

Dry air that's easy on steel

The national corrosion map in the South African Journal of Science found that dry inland areas with about 400 mm of rain a year or less are best rated very low (C1) to low (C2) for corrosion. At De Aar, mild steel corroded at only about 2 µm a year, one of the lowest rates in the country, and well under 1% of the extreme rates measured on parts of the Western Cape coast.

So in the interior you rarely need to pay for coastal-grade coatings. Spend the money on correct fixings, insulation and good flashings instead. If a quote for a Kimberley or Upington house includes a premium marine-grade product, ask what it's for.

Storm winds on open ground

Rain may be scarce, but storms aren't. In early September 2026 a cut-off low brought heavy rain, strong winds and falling temperatures to the province, and Daily Maverick reported residents in the Sol Plaatje Municipality saying the roofs had blown off their homes. Namakwa's climate plan also notes that the contrast between the cooler coast and the hot interior favours strong winds and storms.

Check fixings before the summer storm season. Ask your roofer to confirm every sheet is screwed down along its edges, that ridge capping is secure, and that roof timbers are tied to the walls.