Sudden and significant thermal changes may cause stress on building materials. Tiled balconies, podiums and roof decks are especially exposed to the destructive forces of the elements such as rain, wind, sunlight and cold conditions.
Thermal expansion and contraction occur with shifting temperatures in every building. Paved balconies, podiums, and roof decks (referred to in this document as balconies from here on) are subject to thermal stresses as they are constantly exposed to the elements and the sudden transition between cooler temperatures and the scorching sun.
As a result of UV rays and heat, tiling on balconies expands, and expansion joints are compressed. It is the colour of the tiles that affects their expansion, because darker tiles expand more than lighter tiles. The same is true of highly water-absorbent permeable tiles, such as terracotta tiles.
In multi-level apartment buildings, balconies frequently have minimal falls to the substrate and inadequate subfloor drainage. It is most likely because the fall was incorrect and/or the drainage was inadequate if there is water pooling on the balcony.
Most waterproofing membranes are not designed to hold water between the membrane and the tiles, so they must be installed correctly under the tiles. Consequently, the choice of waterproofing product, installation and tile adhesive has a significant effect. As evaporation occurs, the chemicals in fertilisers can become concentrated, contributing to the breakdown of the waterproofing membrane.
The use of adequate control joints will reduce the likelihood of tiles moving up against each other and popping, potentially destroying the adhesive and waterproofing membrane. Every 3 meters, the joints should be placed around the perimeter of the balcony. The joints will move during thermal changes.
VISUAL SIGNS OF ISSUES:
- Excessive calcium stains (Efflorescence)
- Leaking water into the structure
- The water stains may be seen on the external walls/building facade.
- Water pooling on the balcony floor
- Drummy / Popping / Tenting / Buckled up tiles
Image: Concrete stalactites and stalagmites formed on the balcony.
OUR SUGGESTED SOLUTIONS FOR A LEAKING BALCONY REPAIR:
Rip up and start over again to properly address and repair the underlying problem. If the balcony membrane has deteriorated and failed, then re-grouting and surface sealing is not a permanent waterproofing solution. Ensure correct falls and subfloor drainage and select a cost-effective, long-life membrane that is capable of bridging cracks and joints.
A budget-friendly way to addressing a leaking balcony is reducing the amount of water entering the tile bed by installing a surface sealant, such as a Penetrating Water Repellent, which is a breathable, and non-colour changing surface sealer. The Singapore Waterproofingf PWR is a clear white spirit-based penetrating waterproofing repellent that will cure with a “dry look” offering minimal to no visual change to the substrate. The system penetrates into the substrate reducing the pore size so that liquid can no longer pass through the substrate, yet still allows it to breathe. The PWR system also eases the cleaning of the area and reduces mould growth and dirt build-up, whilst protecting against salt attack and carbonation.
Replacing the existing cementitious grouts with an epoxy grout is another alternative, however that requires re-cutting the grout and installing the epoxy-grout. The epoxy grout is not breathable. If there is considerable water trapped under the tiles after application and/or water can enter under the grouted tiles from elsewhere (i.e. a joint or pipe fitting), then water will do what water does – it will find other exit routes such as a floor to wall joint or the perimeter of the balcony. The results can be unsightly if this occurs.
EFFLORESCENCE ON TILED BALCONIES
Efflorescence usually occurs where a sand and cement bed is placed below a tiled surface. Salts and minerals that are present in the concrete can be drawn up from the tile bed through the grout by capillary action. When the carrier moisture evaporates, the salts and minerals crystallise creating a build-up of efflorescence (free lime/calcium deposits) that appears as white/light grey coloured staining on the tiles, which can have a negative impact on slip resistance.
COMMON REASONS WHY EFFLORESCENCE OCCURS MAY BE DUE TO THE FOLLOWING:
- There was too much water added to the cement mix of the tile bed during the construction.
- The surface was washed down too quickly.
- It was exposed to rainfall too soon, consequently not allowing the cement to bind properly.
- The tiles were installed before the tile bed had dried properly.
- Bad batch of tile adhesive.
TIPS ON HOW TO REMOVE EFFLORESCENCE STAINS:
- If the stains are mild: Clean with a light water blast.
- Mild to moderate stains: Clean with a fit-for-purpose cleaning agent such as CLR (Calcium, Lime & Rust Remover).
- Moderate stains: Clean with Hydrochloric acid, with caution.
- Severe stains: Mechanical removal is necessary.
If you have any issues with water ingress, cracking concrete slabs, structural cracks, concrete deterioration, deteriorated joints, moisture, seepage, efflorescence, rising damp and/or high-flow active leaks in concrete structures, we would be happy to assist you. You are welcome to contact us with any questions that you may have.