Wall & damp proofing Roodepoort

Rising damp comes up from the ground through the brickwork because the damp proof course is missing or has failed, and it shows as a tide mark and salt crystals up to about a metre high. Penetrating damp comes in sideways through the wall from rain, a leaking gutter or a garden bed built up against the house, and it can appear anywhere on the wall. The two need very different fixes, so getting the diagnosis right comes first.

Painting over damp hides it for a few months at best. The moisture is still in the wall and will push the new paint off, usually taking the plaster with it. The wall needs to be dried out and the source of water stopped, then replastered with a salt-resistant plaster before any paint goes on. Damp sealer paints only work once the cause has been fixed.

Many Roodepoort homes are built on sloping stands, so one side of the house has soil against the wall and groundwater runs down the slope towards it after storms. These walls act as retaining walls and need tanking on the soil side or a drainage channel to carry water away. A damp course alone will not stop water coming in sideways.

Injecting a new damp course and replastering a few walls usually takes two to four days of work, but the wall must dry out for several weeks before it is painted. As a rough guide, allow one week of drying for every 25mm of wall thickness. Painting too soon traps moisture and the problem returns.

In Roodepoort, damp proofing is usually priced per linear metre of wall, roughly R350 to R700 per metre for a chemical damp course injection including hacking off and replastering. A single damp wall often costs R3,000 to R8,000, while treating the whole perimeter of a house can run R15,000 to R40,000. Exterior waterproof coatings are priced per square metre on top of that.