Modern Pretoria East homes love a parapet: the flat-roof look in Silver Lakes, Olympus, Woodhill and the newer Moreleta Park estates hides the roof behind a wall. It looks great until water gets into the top of that wall. Then it soaks down through the brickwork and shows up as damp, bubbling paint and efflorescence on a wall nowhere near the roof.
Why parapet walls leak
- Unsealed copings: the flat top of the wall cracks, and every storm pours water straight into the brickwork.
- Membrane stopping short: the roof membrane should run up the inner face and over or under the coping. Often it stops at the bottom.
- Cracks at the slab joint: slab and wall move differently, and the joint between them opens.
- Blocked outlets: water builds up against the parapet and finds the weakest point.
How we waterproof slabs and parapets
We seal cracks, fit a reinforced membrane over the coping and down the inner face, and detail the joint between slab and wall with fabric-reinforced waterproofing so it can move without tearing. On roof slabs we pair this with torch-on or liquid flat roof waterproofing. Outlets are cleaned, and resized if they can't cope with a Highveld downpour.
This is the concrete waterproofing Pretoria work behind most of the "mystery damp" we see in two-storey and flat-roofed homes.
Tell-tale sign
Damp that gets worse a day or two after rain, high on an exterior or upstairs wall, usually comes from above (parapet or slab), not from the ground. Damp at the bottom of walls is usually rising damp.
Concrete slabs over garages, stoeps and patios
Slabs that double as a balcony or sit over a living space need extra care. If people walk on them, see balcony and deck waterproofing. If the slab only sheds rain, a torch-on or liquid membrane with a reflective coat does the job.
Areas we cover for this service
We do concrete slab & parapet waterproofing across Pretoria East: