How does water get into a balcony?
A balcony is a small flat roof that people walk on, with someone else’s ceiling underneath. When its waterproofing fails, the first sign is usually a stain, flaking paint or a drip in the room below, often a neighbour’s. In Cape Town, winter rain, roughly May to August, is driven sideways onto balconies by north-westerly storms, and in summer the south-easter and strong sun open up grout and sealant joints. Near the sea, along the Atlantic Seaboard, in Blouberg, on the Southern Peninsula and up the West Coast, salt air also attacks balustrade fixings and metal edge trims.
Water usually gets in through one of five places, and finding the right one is most of the job:
- Grout and tiles. Grout cracks and turns porous with age, letting water into the screed, and tiles that have lost their bond let more in underneath.
- Screed falls. A balcony should fall gently away from the building towards a drain or edge. If it’s flat or falls the wrong way, water sits on the surface or runs back towards the door.
- Drainage outlets. Drains block with leaves and dirt, and the seal between the waterproofing and the drain body often fails, so water goes around the drain.
- Door thresholds. Many balconies have no proper upstand at the sliding door, so wind-driven rain and pooled water run under the frame.
- Edges and balustrade fixings. Every bolt drilled through the tiles is a hole through the waterproofing, and cracked edges and drip details let water run back under the slab.
We check all five at the inspection, and where it’s not obvious, we trace the water back from where it shows inside.
Over-tile waterproofing vs lifting the tiles
The right method depends on what’s underneath, and we check the tile bond and falls at the inspection so you know which applies before you get a quote.
Over-tile waterproofing is applied directly over the existing tiles. It suits balconies where the tiles are well bonded, the screed is sound and the balcony drains properly. It means less noise, dust and rubble, and usually less time out of use, which matters in an occupied apartment block. We clean the surface, repair cracked grout and joints, seal the drains and thresholds, and apply the system with extra care at edges and fixings.
Lifting the tiles is necessary when tiles are loose or hollow, the screed is breaking up or saturated, or the falls are wrong. We remove the tiles and screed where needed, correct the falls, repair cracks in the slab, waterproof with a membrane suited to a tiled finish, and retile. Larger cracks and joints in the slab are covered in our concrete crack and joint repairs section.
Fixing thresholds, drains and balustrades
Whichever system we use, the details decide whether it works. The waterproofing runs up at the door threshold and is sealed to the frame, drains are cleared and the waterproofing dressed into them, and every balustrade fixing is sealed. Movement joints at the edges and against walls are sealed with Soudal sealants so they can move without opening up.
If the damp is coming down from the wall above rather than through the balcony, see exterior wall waterproofing. Large roof decks and terraces are covered on our flat roof waterproofing page.
Apartment blocks and residents
A leaking balcony affects at least two households, and balconies stacked above each other often share the same detail, so a leak in one unit can be the first sign of a problem in the whole stack. For body corporates and managing agents, we inspect the affected balconies and, where it helps, a sample of the others, then quote each balcony separately so trustees can fix one balcony, one stack or the whole building in phases. See body corporate roofing.
Balcony work happens in people’s homes, so we agree access times with each owner or tenant, tell residents when their balcony will be out of use, protect floors and furniture near the doors, and clear up at the end of each day. Andre or our foreman, Randall, oversees the work, and calls and WhatsApps go to Beverley in the office, so everyone knows who to contact.
Commercial buildings and homes
- Hotels, mixed-use buildings and offices with terraces: work planned around guests, tenants and trading hours, with a health and safety file on larger projects. See commercial and industrial roofing.
- Homeowners: a leaking balcony over a lounge or garage gets the same inspection and choice of systems. See roofing and waterproofing for homes.
The guarantee
Our balcony waterproofing workmanship is guaranteed for 1 to 4 years, depending on the job, as set out in your quote.
Get a free balcony waterproofing quote
Request your quote or send photos of the balcony and the ceiling below on WhatsApp, or see all waterproofing services.