What is Damp Proofing?
- Damp proofing stops moisture from getting into your walls and floors.
- Damp (excess moisture) comes from the ground below or rain from outside.
- It makes your walls wet, cold, and full of mould.
- Mould is bad for your health - especially for kids and older people.
- Damp proofing fixes the problem at the source - not just the surface.
- It is different from waterproofing (which deals with liquid water).
- Both are important - a professional will tell you which one you need.
Types of Damp Proofing
Rising Damp Treatment
- •Rising damp is ground moisture travelling up through your walls.
- •It looks like a damp tide mark on your lower walls - usually 1m high.
- •You often see salt crystals, paint bubbling, or plaster falling off.
- •A chemical is injected into the wall to form a barrier that water cannot cross.
- •This is called a DPC injection (Damp-Proof Course injection).
- •After treatment, the affected plaster is removed and replaced.
- •Takes a few weeks to fully dry out after treatment.
Penetrating Damp Repair
- •Penetrating damp is rain or outside water soaking through your walls.
- •It is common in older homes with solid walls (no cavity inside).
- •Cracks in the walls or mortar let rain soak straight through.
- •Signs: damp patches that appear after rain, usually higher up on walls.
- •Cracks are repaired and a waterproof render or coating is applied outside.
- •Window sills and lintels (above windows) are common entry points.
- •Also check gutters and downpipes - overflowing water causes penetrating damp.
Damp-Proof Course (DPC)
- •A DPC is a barrier built into the wall to stop ground moisture rising.
- •New buildings have a DPC built in - a layer of plastic or slate low in the wall.
- •Old buildings may not have one - or it may have broken down.
- •If the DPC is missing or broken, rising damp becomes a serious problem.
- •A new DPC can be installed by chemical injection or by cutting a slot in the wall.
- •Chemical injection is the most common modern method.
- •Once installed properly, it lasts for decades.
Signs You Have a Damp Problem
- Wet or damp patches on your internal walls.
- Paint or wallpaper peeling or bubbling.
- A musty smell inside the home.
- Black mould spots growing on walls or ceilings.
- Salt crystals or white powder on brick walls.
- Floors that feel cold and damp.
- Condensation on windows and walls - especially in winter.
How Much Does Damp Proofing Cost?
- DPC injection per linear metre: R200 – R500.
- Rising damp treatment for a small room: R3,000 – R8,000.
- Penetrating damp repair (per wall): R2,000 – R6,000.
- Full home damp proofing: R10,000 – R40,000+.
- Prices depend on wall thickness, size, and how bad the damp is.
- Delaying treatment always makes it more expensive - act quickly.