The Necessity of Waterproofing Over Ceramics
The surface of ceramic tiles is water-resistant; however, the grout joints on the surface can crack, open up, or increase water permeability over time. Furthermore, water can accumulate in the voids behind the tiles, which eventually leads to water damage on the underlying surfaces. Especially on outdoor ceramic floors, rainwater can seep under the tiles and damage the reinforced concrete structural elements. Therefore, applying an extra waterproofing layer over existing ceramics is often necessary.
Key Considerations When Choosing a Waterproofing Material for Ceramics
The waterproofing material to be applied over ceramics must meet the following technical criteria:
- It must have high adhesion (bonding strength) to the surface.
- It must exhibit elastic properties.
- It must be UV-resistant (for terraces or outdoor areas).
- It must be walkable or suitable for subsequent coverings.
- It must be breathable with good water vapour permeability.
- It must have high chemical resistance.
Waterproofing Materials Applicable Over Ceramics
Below are the main waterproofing materials that can be applied over ceramics, along with their features:
1. Transparent Polyurethane-Based Waterproofing Materials
These transparent products prevent water ingress without compromising the existing ceramic appearance. They are manufactured as single-component or two-component systems. Upon application, they form a transparent and glossy film layer.
Advantages:
- Does not change the ceramic appearance.
- No need for an extra covering layer on top.
- Easy application with a brush or roller.
- Exhibits high elasticity after drying.
Points to Note:
- The surface must be dry and clean.
- Grout lines must be confirmed to be intact and clean.
2. Liquid Membrane Systems
Polyurethane, acrylic, bitumen-polymer, or hybrid-based liquid membranes create a barrier against water by coating the ceramic surface. These products are typically applied with a brush, roller, or airless spray.
Advantages:
- Easily penetrates details.
- Thickness control is possible when applied in multiple coats.
- Some types are UV-resistant and suitable for terraces.
Points to Note:
- Some types are not suitable for tiling over.
- Primer use may be required before application.
3. Transparent Waterproofing Materials (Liquid Glass)
Another option that can be applied over ceramics is the transparent insulation product known as liquid glass. These are typically breathable, water-repellent coatings.
Dryfix Liquid Glassy 100 is a waterproofing product that can be easily applied to various surfaces such as ceramic, marble, granite, tile, natural stone, and concrete.
Advantages:
- Odourless and environmentally friendly.
- Generally safe for use in interior spaces.
- Provides protection without spoiling the look of the ceramics.
Points to Note:
- Long-term UV resistance in outdoor environments may be limited.
- May not be suitable for areas with very high water load.
4. Epoxy-Based Waterproofing Materials
Epoxy resin-based systems are generally applied over ceramics in enclosed areas. They are preferred in places with high humidity, such as food facilities, laboratories, and industrial kitchens.
Advantages:
- High mechanical and chemical resistance.
- Provides a long-lasting coating.
- Anti-slip surface properties can be achieved.
Points to Note:
- Not resistant to UV light.
- Application requires expertise.
5. Rubber-Reinforced Polymer Coatings
These highly elastic, water-resistant, and impact-resistant coatings are particularly preferred on moving substrates. Some versions can be applied directly over ceramics.
Advantages:
- High flexibility and crack-bridging ability.
- Resistance to hot-cold thermal cycles.
- Usually solvent-free, environmentally friendly formulations.
Surface Preparation Before Application
Proper surface preparation is crucial before applying waterproofing over ceramics:
- Cleaning: All dust, oil, detergent residue, and old coatings on the ceramic surface must be thoroughly cleaned.
- Joint Control: Voids, cracked grouts, or loose tiles must be identified and repaired.
- Dryness: The surface may need to be dry, depending on the chosen insulation material.
- Primer Use: Surface adhesion should be increased with special primer products for some insulation systems.
Post-Application Considerations
- The curing time must be waited as per the manufacturer's technical instructions.
- If a new covering will be applied (e.g., tile, parquet), the applied waterproofing material must be compatible with that covering.
- For products applied outdoors, UV resistance and water vapour permeability must be considered.
The Advantage of Waterproofing Over, Not Under, Ceramics
For those who want to solve waterproofing issues without carrying out extensive renovation, insulation systems applied directly over the ceramics—without removing the tiles—offer a significant advantage in terms of cost, time, and labour. This is ideal, especially for tenants or those seeking a temporary solution.
Where Can They Be Used?
Waterproofing materials applicable over ceramics are generally used in the following areas:
- Terraces and balconies
- Bathroom and shower areas
- Around washbasins
- Kitchen backsplash areas
- Pool surrounds
- Commercial areas (restaurants, hotel bathrooms, etc.)
Waterproofing systems applied over ceramic-tiled surfaces are highly effective in extending the lifespan of buildings, preventing damage to lower floors, and addressing problems such as dampness, moisture, and water leaks. Proper product selection, correct surface preparation, and application according to instructions are critical to the system's success.
It should be remembered that the condition of every ceramic surface, the water load it will be exposed to, and the application area are different. Therefore, the decision should be made after a detailed evaluation of the technical characteristics of the insulation system to be used. It is recommended to seek support from a technical expert before application if necessary.
It is difficult to ensure water tightness on ceramic surfaces; therefore, insulation products that adhere strongly to the surface, are transparent, and have an elastic structure should be preferred. Dryfix offers specially formulated solutions for over-ceramic waterproofing that both preserve aesthetics and provide long-lasting results.