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How to Waterproof a Balcony Before Tiling

Collins is a B.Sc. environmental science graduate who is passionate writing about health and fitness, technology, business and finance.

Tiling improves the aesthetic of your balcony wall and floor. However, you should remember that installation of any balcony tiles design is a decorative finish and does not function as an absolute moisture barrier. Due to this, you need to waterproof balcony flooring before tiling because nobody desires to tackle a leaking balcony in the future, do you?

Balcony waterproofing before tiling is necessary to protect the substrate from constant water seepage. The operation is crucial in sealing the balcony to ensure it does not permit any water to infiltrate your house, resulting in expensive water damage.

Improperly waterproofed tiled balcony may cause many issues, including moist surfaces, peeling paint, and additional structural complications that may be costly to resolve. Read on to learn the vital balcony waterproofing details to avoid dealing with such expensive problems.

Waterproofing A Balcony Before Tiling

Building a waterproof balcony depends on the state of the substrate, in addition to sufficient sloping. Though the waterproofing process is not sophisticated, you need to engage a balcony waterproofing contractor to realize the best result. Before then, let’s look at the different waterproofing technique you can employ on your balcony.

Methods Used For Waterproofing A Balcony

You can choose from several methods of waterproofing a balcony before tiling. All these balcony waterproofing systems feature a water-tight material that is useful in sealing the floor substrate against moisture.

But, you must assess specific parameters before choosing the best solution for waterproofing a balcony. To make the right choice, you need to examine the state of balcony flooring, and layered part of the balcony substrate. Also, check the flooring slope and ensure it is of the correct gradient, and if there exists no separation or cracks between the different layers.

Based on the condition of your balcony after assessment, you can select one of these methods to waterproof the balcony before tiling.

  1. Balcony Waterproofing Membrane. You will find different waterproofing membranes on the market, with rolled bituminous balcony waterproofing membranes as the most common type. Other types of sheet membranes used to waterproof a balcony before tiling includes polyurethane membrane, EPDM membrane, TPO and PVC membrane.
  2. Liquid-Based Waterproofing Membrane. This come in a liquid state that you can apply by brushing or spraying on the balcony surface. The liquid dries in the air to cast a flawless, joint-free membrane. You can control the thickness by spraying more fluid per unit area. These are broadly rated as the best waterproofing membrane since they are joint-free nevertheless, you must be careful to give the correct thickness because the membrane may break or tear when it is thin excessively.
  3. Cementitious Waterproof Coating. The system uses two-component mixtures over your balcony flooring, and has an excellent affinity to masonry and concrete substrates, hence strong bonding strength. Moreover, the polymer modifier brings on the versatility features of this solution.

Before starting the operation, inspect the flooring for holes and cracks. If present, undo the floor surface finish and check the substrate (conventionally concrete or wood) for defacement. Moreover, ensure that the balcony maintains a gradient of not less than 1/4 inch per foot (2 percent) for positive drainage.

That said, let's now look at the main steps to waterproofing your balcony.

1) Preparing surface for waterproofing. First, confirm that your substrate material is compatible with the waterproofing system you intend to use. You will not use any particleboard; therefore, the substrate needs to be impervious to moisture damage. The substrate should be clean, dust and contamination-free, and dry (priming might be necessary for some types of balcony waterproofing systems.

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2) Applying waterproofing system. Apply the balcony waterproofing solution of your choice according to the manufacturer's specifications. Apply at least 2x layers when you opt for a liquid waterproofing membrane. If a screed is necessary, apply another 2x layers of the waterproof balcony membrane above the screed and give it time to cure.

Remember to safeguard the chosen waterproofing system from traffic during the coating and curing phase. If applying a water-sensitive product, ensure not to install it when it is likely to rain during curing.

3) Applying fillets. You will need to install fillets where a sheet membrane switches from the horizontal to a vertical plane (like where the balcony floor intersects with the side walls).

4) Terminating waterproofing membrane. The final height of the balcony waterproof system above the finished flooring level should be adequate to inhibit water seeping over the top. It is advisable to return the waterproofing membrane about 70 to 180mm up the balcony wall based on the skirting tiles you use.

5) Connecting waterproofing system to drainage. Connect the balcony waterproofing membrane to your home's drainage system. You do this via the membrane turn-down into the water drainage system inlet. However, you can only do this kind of connection if the balcony features a strip drain or center drain system.

6) Installing tiles on the balcony. The balcony tiles should be compatible with the waterproofing solution. For this reason, you should have the same person install the two systems. Working with one installer eliminates the possibility of a balcony waterproofing contractor installing a system not consistent with the tiles or tiler destroying the sheet membrane during tiling.

Additional Guidelines To Waterproof A Balcony Before Tiling

Water leakage can have destructive consequences to your building if you do not take enough time to waterproof the balcony correctly.

Therefore, you need to pay attention to these waterproofing tips in addition to the balcony waterproofing details already discussed in this post.

  • It is also essential to support pipes and fittings with a suitable waterproofing adhesive to fill any gap. These are crucial sections where water seepage and subsequent damage may occur.
  • The other critical region to seal up is the intersection between any walls and the balcony floor, where there is the possibility of water leakage. In addition to thorough waterproofing, you must use a non-shrinking grout to close up this high-risk section.
  • The balcony is ready for waterproofing only after preparing the substrate properly. The more versatile and better-performing solution, the more reliable the waterproofing system for the terrace will be.

Why You Need To Waterproof A Balcony Before Tiling

Most people disregard waterproofing balcony flooring, which costs them substantially down the line. Besides making your porch pleasant in all weather, waterproofing outdoor balcony is essential for conserving your building.

Exterior balcony waterproofing also improves the durability of your tile and hinders water and moisture from defacing the substrate. When water seeps into a small gap, it can speedily result in deterioration and other structural destruction. Moreover, in some instances, failure to deal with the problem could invalidate your property insurance coverage.


Building a waterproof balcony is a rigorous, complicated operation that needs a high level of preparation and detail. Not only should you prepare the balcony properly before installing the waterproofing system, but applying the products correctly and systematically is also essential.

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