Why is my balcony leaking? Causes, heavy rain and what to do
Balconies take the full force of Sydney's sun and storms. When water shows up on the ceiling below, at the door sill or on the slab edge, one of these is usually the cause.
The common causes
Failed grout
Outdoor grout wears faster than indoor grout. White deposits on the grout or slab edge show water moving through the concrete.
Cracked perimeter joints
The joints where the floor meets the walls, door sill and balustrade need to be flexible. When they're grouted solid or the sealant splits, water gets in at the points that matter most.
Drainage and falls
Ponding water and blocked or small outlets keep the surface wet for longer. Clearing leaves from the outlet is an easy first check.
Door sills
If the joint under a sliding door wasn't sealed properly, driving rain gets in. It often shows up as wet carpet or floorboards after a storm.
Balustrade posts
Posts fixed through the tiles leave holes that must be sealed. Rust stains at the base are a warning sign.
A failed membrane
If the membrane under the tiles has failed, water that gets through the surface isn't stopped.
Why it only leaks in heavy rain
Light rain wets the surface and dries off. Heavy, wind-driven rain soaks the grout and bed, overwhelms the outlets, ponds against the door sill and is driven into the joints. The leak can show up hours after the rain stops, as water works its way through the slab.
Balcony leaking into the room or unit below?
Photograph the damage with the date and note whether it follows rain. In an apartment, tell your strata manager in writing, because the balcony membrane is usually common property. The source isn't always directly above the stain, so we check both the balcony and the area below.
When to get it inspected
- As soon as water appears inside, on a ceiling below or at a door sill
- When white deposits, rust stains or bubbling paint appear on the slab edge
- When tiles crack, lift or sound hollow
The longer water sits in the bed, the more likely the tiles come loose and the repair grows.
Repair options
Sound tiles suit a regrout and seal without removing tiles. Widespread surface wear may suit a trafficable membrane. Loose tiles, wrong falls or poor drainage may need a strip-out. Compare the three options for a leaking balcony.
Every property is different. This guide is general information, not a diagnosis of your leak. Book a free inspection for advice on yours.
Leaking shower or balcony?
We'll inspect it and quote for free, anywhere in Sydney. If the tiles are sound, we can usually stop the leak without lifting them. The sealing product we use carries a manufacturer's product warranty of up to 25 years, under the manufacturer's terms.