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April 4, 2022
Waterproofing and Renovation
Case Study: Dampness and Peeling Plaster
Solution: Internal Waterproofing Coating + Renovation
Solution to the Problem in 7 Steps
Internal Mineral Waterproofing + Application of Renovation Plasters
Step 1: Surface Cleaning
Remove the existing plaster and clean all loose elements using a steel brush. Mechanically remove brittle joints and chip them to a depth of approximately 2 cm, reaching a stable material.
⚠️ Note: The substrate must be load-bearing, even, and clean, and it should also be insulated against water penetration from below.
Step 2: Joint Filling
Fill the joints using Bostik Sperrmörtel repair mortar. The mortar sets within approximately 4-5 hours at a temperature of 20°C.
Step 3: Application of Mineral Slurry
Apply K11 Schlämme Grau mineral slurry. Ensure the substrate is pre-wetted to a matt-damp condition before application.
Note! The mortar must be applied in at least two working cycles! The second layer should be applied perpendicularly to the first layer. The mortar must cover 100% of the surface intended for sealing. The thickness of each layer should not exceed 2.5 mm at any point.
Step 4.
Embed the BOSTIK Ardatape Sanitary Band or KOESTER Flex-Tec 120 sealing tape into the first layer of K11 Schlämme Grau waterproofing slurry at wall-floor and wall-wall junctions.
Step 5.
Apply the next layer of K11 Schlämme Grau mineral slurry only after the first layer has set. Remember to moisten the substrate with water before applying the second layer of waterproofing slurry.
Note! The second layer should be applied perpendicular to the first layer. The slurry must cover 100% of the surface intended for sealing. The thickness of each layer should not exceed 2.5 mm at any point. Extend the slurry onto the floor for a minimum width of 30 cm and onto the adjacent walls.
Step 6.
Apply the wide-pore render KÖESTER Sanierputz in a single work cycle at a thickness of 20-25 mm. Highly absorbent substrates should be pre-moistened or primed with a diffusion-permitting primer such as KOESTER Polysil TG500 or BAUMIT SanovaPrimer. Remove any excess material while ensuring the coating is applied evenly. Finally, smooth the render surface.
Fun Fact! In this case, there’s no need to apply a renovation coat since KÖESTER Sanierputz is applied directly as the main layer.
However, if you need to use a renovation coat, you can also utilize KÖESTER Sanierputz. When used as a renovation coat, it must cover 50% of the surface. In this scenario, the KÖESTER system should be applied as follows:
Immediately after priming the substrate with KÖSTER POLYSIL TG 500, apply the renovation coat "fresh on fresh." This renovation coat should be made using KÖSTER Sanierputz grey, mixed with a 10% addition of KÖSTER SB Haftemulsion in the mixing water. The renovation coat should be applied to the substrate at a thickness of approximately 5 mm and should cover a maximum of 50% of the surface (material usage for KÖSTER Sanierputz grey to create the renovation coat is about 3.0 kg/m²).
Step 7.
At this stage, you can coat the plasters with KABE Aquatex paints or other paints specifically designed for renovation plasters.
Note!
The air, substrate, and component temperature should range from +5°C to +30°C.
What You Need for Waterproofing and Renovation?
Repair Mortar: Bostik Sperrmörtel
Mineral Slurry: K11 Schlämme Grau
Sealing Tape: BOSTIK Sanitary Band
Wide-Pore Plaster: Koester Sanierputz
Paint: KABE Aquatex
Wanna know more?
We have a team of experts who will gladly assist you.
If you have any additional questions, feel free to call us at 533 343 595.
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Author: Anna Kaczmarczyk-Fiuk
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Substantive and Technical Editing: Szymon Ziąbek
