What is balcony waterproofing?
Balcony waterproofing is a flexible waterproof layer installed on the balcony slab under the tiles, turned up the walls and under the door threshold, and sealed into the drain outlet. Because balconies are exposed and the slab cantilevers, the membrane must be flexible enough to handle movement and temperature changes.
Correct falls towards the outlet, a drip edge at the slab front and a proper detail at the door sill are as important as the membrane itself.
Benefits
- Stops seepage into the flat below and under the door into the room
- Correct falls so water drains instead of ponding
- Door sill and outlet details, where most balcony leaks begin
- Suitable for new construction and for repair of existing balconies
Common problems and applications
Problems it solves
- Damp patches and dripping on the ceiling of the balcony below
- Water entering the room under the sliding door or French window
- Ponding due to poor falls or blocked outlets
- Hollow, cracked or open tile joints
- Efflorescence and spalling on balcony soffits and edges
Where it is used
- Apartment balconies and utility balconies
- Decks and sit-outs at podium or terrace level
- Chajjas and window projections
- Refuge floor areas in high-rise buildings
Our balcony waterproofing process
Inspection
We check tile condition, joints, falls, outlet, door sill and the ceiling below to locate the entry point.
Decide the repair level
Leaks from open joints may be solved by epoxy re-grouting; a failed membrane needs tile removal and re-waterproofing.
Strip and prepare
Tiles and bedding are removed, the slab is cleaned and cracks repaired.
Falls and coving
Falls are formed towards the outlet and coving is made at the wall junctions.
Membrane and details
A flexible cementitious or PU membrane is applied with fabric at corners, outlet and door sill, turned up the walls.
Ponding test and retiling
The balcony is ponded and checked from below before re-tiling with sealed joints.
Materials and systems used
- Flexible cementitious coatings
- Two-component polymer coatings applied under tile adhesive.
- Liquid PU membranes
- For exposed decks or where higher elasticity is needed.
- Epoxy tile grout
- Seals tile joints against water ingress.
- Reinforcement fabric
- At corners, outlet and door sill.
Products are selected from the approved specification. Coverage, thickness and curing follow the manufacturer's current data sheet.
Why professional waterproofing is important
Balcony leaks affect two homes: yours and the one below. Quick fixes like silicone on tile joints rarely last, because water already sits under the tiles. A proper job fixes the falls, seals the membrane into the outlet and under the door sill, and is ponded before tiling.
Doing it right once avoids repeated tile replacement and the damage to the ceiling and plaster below.
Why choose us
- Clear repair options
- We explain when re-grouting will work and when full re-waterproofing is needed.
- Door-sill expertise
- Thresholds are the most missed detail; we treat them every time.
- Ponding test before tiling
- Every balcony is tested and checked from below.
- Clean work in occupied homes
- Dust control and debris removal for work inside flats.
Read more about our team and how we inspect and record work.
Frequently asked questions
Which waterproofing is used for balconies?
A flexible two-component cementitious coating or a liquid polyurethane membrane is applied on the balcony slab under the tiles, turned up the walls and taken under the door threshold, with reinforcing fabric at corners, the outlet and the sill. Correct falls to the outlet and epoxy-grouted tile joints complete the system.
Can a balcony leak be fixed without removing tiles?
If the leak is only through open tile joints and the membrane below is intact, epoxy re-grouting can work. If water has been entering for a long time or the membrane has failed, tiles must be removed.
Why does water come in under my balcony door?
Usually the balcony falls towards the door, or the membrane does not continue under the threshold. Both are corrected during re-waterproofing.
How long does balcony waterproofing take?
A typical apartment balcony takes a few days including membrane curing and a ponding test before tiling.
