Waterproofing Our Bathroom - Part 1

Damp walls are cold walls - water and moisture that is allowed to pass through a wall onto it's inner surface will inherently maintain that area at a cooler temperature than its surroundings. When this allowed to happen it can cause condensation build up and black mould growth. Also, it is important that you have a good seal around the shower area at your home in order to prevent water escaping down the side and causing water damage on your ceiling or floor below. To prevent this from happening, here are some helpful information to make your shower totally waterproof.

Insulation 1 1


The bathroom is the most expensive and the room most exposed in the house to water. Modern bathroom fixtures, elegant tiles, original design, the cost of contractors - all this is a waste of money if we do not make good bathroom seals. For this reason only reliable materials and sealing technologies are worthwhile.

Waterproofing is to protect the room from the damaging effects of moisture and water. Although it seems that the lining of the tiles is tight, it is not entirely true. Water can soak under the glaze through a mesh of joints. Particular danger is caused by any damage to the joints - cracks or cavities, which water can get into. The waterproofing layer ensures that the water does not soak below the layer effectively separating the wet and dry zones.

Wet places, exposed to water, which require sealing:
- floors
- drainage of water in the floors
- walls where water is poured (showers, walls next to the bath)
- connections between shower trays and rest of the floor or walls


The lack of waterproofing in water-exposed areas carries many long-term complications. Water that enters the dry zone can cause damage which we will see later. It is very important that waterproofing is applied appropriately, otherwise it can be counterproductive.

Effects of improper sealing of the bathroom:
- damp fungus molds (mold and home fungus are carcinogenic)
- leaks, droplets and dampness in neighboring rooms, possibly also in neighboring areas
- need to re-make a very expensive repair combined with tiling, drying of walls / floors, often plastered, proper sealing, tile adhesion

1. Degradation of tiles/stone edges
Water penetrating the concrete floor causes that alkaline contained in the concrete are drawn to the surface of tiles. It degrades the tiles / stones, in extreme cases leading to even the top of the entire edges along the joints.
2. Floor and walls discoloration
Also caused by the resulting alkaline due to soaked concrete.
3. Fungus, mold and bad smell
The damp surfaces of water-soaked ceilings and walls are extremely exposed to fungus and mold, which are bad for health and cause bad odors. Their development can be seen inside the shower cabin, on the rest of the bathroom, on walls next to shower cabin and on the ceilings of the rooms below.
4. Degradation of thermal & acoustic insulation
In case of ceilings containing styrofoam boards (thermal and acoustic insulation), the water permeating the floor lies around the polystyrene, causing its gradual degradation over time.



Sealing mat is made of a polyethylene film coated with a special non-woven fabric on both sides, so that it bonds well with the glue layer. Its installation is recommended in all areas that require sealing whole walls and edges or corners as well. The mat, compared to tanking liquid, is resistant to the cracking of the substrate, ensuring the sealing of the entire surface. It also reduces installation time, allowing the tiles to be laid immediately after gluing the mat.


Tanking liquid is a special waterproofing material sold in plastic buckets. Creates a flexible, airtight coating. Layers should be applied to dry, clean surfaces of walls and floors. When the substrate is absorbent it is worth priming it first. When using tanking liquid we should also use sealing tapes. We use them on connections between different materials and structures, such as the drain flange and the floor. Tiles can be glued onto tanking liquid using an adhesive that is designed for use on flexible substrates with negligible absorbency.

As you can see, good insulation is necessary and without it our dream bathroom can end up quickly. Check out our blog more often as we will be discussing the steps and products required to complete our bathroom seal in the next guide.

Alex D.

Expertise: Bathroom Finishing, Shower Installations, Plumbing

About Alex

Alex D. is a skilled installer with extensive experience in bathroom finishing and plumbing. Known for his meticulous work in creating custom walk-in showers and installing wet room shower trays, Alex brings both precision and creativity to every project. His hands-on expertise ensures that each bathroom he works on is not only visually appealing but also functionally superior.

Areas of Specialization

Walk-In Showers: Alex has a particular talent for designing and installing walk-in showers and wet room shower trays, transforming ordinary bathrooms into modern, accessible spaces.

Bathroom Plumbing: With a comprehensive understanding of bathroom plumbing systems, Alex ensures that all installations are executed flawlessly, resulting in durable and efficient setups.

Commitment to Quality

Dedicated to the highest standards of workmanship, Alex continually updates his skills to incorporate the latest techniques and materials in the industry, guaranteeing that each bathroom he works on is a testament to quality and craftsmanship.

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