Stop balcony leaks in their tracks

In many parts of the country, the rainy summer season is upon us, and there’s nothing more frustrating than a leaking balcony or roof. The experts from TAL gave us some top advice on how to make sure your balcony or outside area is properly waterproofed. 


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If you see signs of a leak or water damage below a waterproofed and tiled balcony or terrace, chances are that the area either wasn’t waterproofed properly, wasn’t waterproofed before it was tiled, that the waterproofing is damaged or that the floor water outlet is not draining properly and is flooding the balcony.  
Some tiles, particularly porous natural stone tiles and even light-coloured ceramic tiles may change colour when the tile installation is experiencing moisture seep from the surface of the installation. To determine the problem, consult a professional tiling contractor who’ll be able to work out whether the problem is related to failed waterproofing and/or cracked grout. If the waterproofing system has failed, it’s generally advisable to remove the tiles and start the waterproofing and tiling process from scratch.
You can waterproof and tile over existing tiles, provided the existing tiles are in good condition and firmly attached to the substrate. Make sure that the tiles are not cracked, loose or hollow sounding, and that the level of the current floor allows for a height increase, especially concerning door entrances.
Keep in mind that the tile installation is an aesthetic finish and doesn’t act as a complete moisture barrier.

TAL offers TAL Superflex1, an acrylic-based liquid waterproofing system. This specific acrylic-based system does not re-emulsify if exposed to water once fully cured, and is also UV resistant and flexible.


Waterproof the substrate with a waterproofing compound such as an acrylic-based liquid waterproofing system available from tile and home improvement retailers.


  • Primer
  • Waterproofing system
  • Reinforcing membrane
  • Block brush
  • Roller
  • Silicone sealant


Step 1: Priming

  • The substrate must be in good condition, clean and dry.
  • Prime rough, porous surfaces with the floor primer and smooth, dense surfaces with a TAL Floorkey slurry coat (one part TAL Floorkey to two parts tile adhesive powder or 1.5 parts ordinary Portland cement, by volume).
  • Paint the primer onto the surface using a block brush, and allow to dry completely before proceeding.


Step 2: Application:

  • To allow for movement, apply a 10mm silicone bead in all internal corners and interfaces. Due care must be taken to ensure that the silicone bead is not flattened out. Allow the silicone to cure for approximately 12 – 24 hours.
  • For the corner and interface applications, apply the first coat of the acrylic-based waterproofing system (such as TAL Superflex1) to these areas. Immediately bed the membrane into the wet liquid waterproofing system, ensuring that there are no wrinkles or air bubbles trapped beneath the membrane. The membrane must be pushed into the corners, ensuring that the entire interface is covered with the membrane. Apply a second coat of liquid waterproofing system to completely saturate the membrane before the first coat dries.
  • For the main area application, apply the first coat of the acrylic-based waterproofing system over the clean, primed surface. Immediately bed the membrane into the wet acrylic-based waterproofing system. Ensure that there are no wrinkles or air bubbles trapped beneath the membrane and that the membrane is adhered to the substrate by pressing the membrane with the roller in two different directions. Apply a heavy coat of the acrylic-based waterproofing system over the membrane to completely saturate the membrane before the first coat dries.
  • Ensure that the main application overlaps the corner applications by at least 50mm.
  • Allow the acrylic-based waterproofing system to dry completely (at least three days, depending on ambient conditions) before starting your tiling.
  • Don’t start the waterproofing application if it is about to rain as rain will dilute uncured acrylic-based waterproofing system and cause run-off. Protect the system from rain or water immersion for at least three days after application.

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Step 1: Tile selection

  • Use slip-resistant and textured tiles when tiling an exposed and wet area. Avoid smooth and polished tiles. Remember that natural stone tiles require sealing after installation.


Keep in mind that a latex-based additive improves the water resistance of the adhesive and grout, but doesn’t make the installation waterproof.


Step 2: Adhesive and grout system:

  • It is always recommended to use rapid or quick-setting adhesives as due to the impervious nature of the waterproofed substrate, standard-setting adhesives will take longer to set.
  • The adhesive and grout system has to accommodate thermal expansion and contraction in the installation due to temperature fluctuations and frost. The tile installation also has to be water resistant as it will be exposed to rain.
  • Use a water resistant and flexible adhesive and grout system to install the tiles. This system is achieved by mixing the adhesive and grout with a latex additive.
  • When using a latex based additive in the adhesive or grout mixture, it is important to use the full amount of additive as stipulated in the instructions on the packaging. The latex additive should be used as a total water replacement in the mix. Do not dilute the latex-based additive with water as this will weaken the mix strength and the adhesive and grout will not perform to their designed specifications in terms of enhanced flexibility and water resistance.
  • Seal the grout and porous tiles after installation.


TAL products are available from major tile merchants and home improvement retailers. Visit the TAL Talk blog where you’ll find handy tips to guide you when tiling, visit the website or contact the TAL Technical Advisory Service on 0860 000 (TAL) 825 for on-the-job support.



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