Waterproofing and damp proofing in North West

Rustenburg's black clay

The black clay of the Rustenburg area, formed from weathered norite, is listed among the most highly expansive soils in South Africa, according to a soil-testing paper published by the US Transportation Research Board. Its dominant mineral is smectite, a clay mineral known for swelling when it takes up water.

When this clay gets wet next to a wall and stays dry elsewhere, it heaves unevenly, and the walls crack. Those cracks are then where rain gets in. So the cheapest long-term fix for damp in a cracked house on Rustenburg clay is often controlling water at ground level:

• Downpipes discharging into channels or drains, not onto the soil beside the wall.
• A paved or concrete apron around the house that falls away from it, with sealed joints.
• No garden beds, lawns or irrigation hard against the foundations.
• Flexible fillers and elastomeric coatings for wall cracks, rather than rigid plaster patches.

Leaking pipes on dolomite: Potchefstroom and Stilfontein

A 2016 study of dolomite risk management in what was then Tlokwe, now JB Marks, counted 5,693 stands affected by dolomite around Potchefstroom. It found that much of the old underground water infrastructure didn't meet current standards for dolomite, and that some of it was assumed to be leaking extensively. Water running into dolomite from a single point can wash out the soil above it and start a sinkhole.

In April 2026, OFM News reported sinkholes at intersections on Stilfontein Road, on the N12 between Potchefstroom and Klerksdorp, caused by a leaking water pipe at the old reservoir in Stilfontein. If your home is in a dolomite area, a leaking shower, geyser drain or downpipe is a ground-stability issue as well as a damp one. Get a plumber to rule out leaks before waterproofing, and report ground cracks or hollows to the municipality.

Waterlogged homes after storms

The same April 2026 storms left homes waterlogged in Seraleng and Ramochana in Rustenburg, and blew roofs off houses in Khuma and Mamerotse. When floodwater has stood against or inside a house, the walls need to dry out fully before replastering, and the damp-proof course should be checked rather than assumed to be working. Ask the contractor for moisture readings before they quote for finishes.