by Dr E. Ramanathan PhD
Water Leakage Prevention
Water leakage through terraces is a complex issue and cannot be permanently fixed by a single-layer waterproof coating. A multi-layered system combining external and internal treatments is essential to ensure durability and effectiveness. Here’s how the system works step-by-step:
🔹 1. Crack Filling (Internal & External Sealing)
- Purpose: Seal visible and hairline cracks that act as water entry points.
- Materials:
- External Cracks: Elastomeric crack fillers, polyurethane sealants.
- Internal Cracks (beneath surface): Cementitious injection grouts or epoxy grouts.
- Note: Cracks must be chased (opened), cleaned, and properly filled.
- Grouting is an inevitagle stage to arrest penetration of water through cracks on terrace.
🔹 2. Primer Coat (Bonding Layer)
- Purpose: Improve adhesion between substrate and waterproof layer.
- Materials:
- Acrylic, polyurethane, or epoxy primers.
- Penetrating primers for porous surfaces like concrete.
- Function: Seals pores and dust, strengthens surface.
🔹 3. Waterproof Membrane or Coating
- Purpose: Form a continuous, flexible waterproof barrier.
- Materials:
- Cementitious coating (for under tiles)
- Elastomeric acrylic/polyurethane membrane (exposed roof)
- Layers: Typically applied in 2–3 coats in cross directions.
🔹 4. Protective or Finish Coat
- Purpose: Protect waterproof layer from UV, wear, and standing water.
- Materials:
- Cool roof coatings, tiles, screed or PU topcoat
- Optional slope screed (1:100) to drain water
- Importance: Prevents mechanical damage and UV degradation.
🔹 Optional Enhancements
- Geotextile Fabric Reinforcement: Embedded between coats over joints and cracks.
- Tile Protection: Use tile adhesive over cured coating if tiling is planned.
Summary Table:
| Step | Function | Material Type |
|---|---|---|
| 1. Crack Sealing | Prevent water entry | Crack fillers, grouts |
| 2. Primer | Improve bonding | Acrylic, PU, Epoxy |
| 3. Membrane | Core waterproof barrier | Elastomeric, PU, Cementitious |
| 4. Topcoat/Protection | UV/mechanical protection | Cool roof coat, screed |
Contact us if you want a ready reference SOP or product suggestions.
Terrace Retiling
Types of Waterproof Coatings
Waterproof coatings are protective layers applied to surfaces to prevent water penetration. Common types include:
1. Acrylic-Based Waterproof Coatings
- Use: Roofs, terraces, walls.
- Features: UV resistant, flexible, waterborne.
- Example: Elastomeric acrylic coatings.
2. Polyurethane Coatings
- Use: Flat roofs, decks, wet areas.
- Features: Seamless, highly elastic, abrasion-resistant.
- Type: One- or two-component systems.
3. Bituminous Coatings (Asphalt-based)
- Use: Foundations, basements.
- Features: Economical, good adhesion, UV-sensitive unless modified.
4. Epoxy Coatings
- Use: Concrete floors, water tanks.
- Features: Hard, chemical resistant, but less flexible.
5. Cementitious Coatings
- Use: Bathrooms, swimming pools, water tanks.
- Features: Easy to apply, cost-effective, good bonding with concrete.
6. Silicone/Silane/Siloxane Coatings
- Use: Brick, masonry, and natural stones.
- Features: Penetrating, breathable, long-lasting hydrophobic effect.
7. Polyurea Coatings
- Use: Industrial and commercial roofing, containment.
- Features: Fast curing, highly durable, flexible.
Let me know if you want formulation details, application methods, or comparison charts. Contact me in WhatsApp 9444929163 and fix up an appointment for 4 weekly meeting on Thursday or Saturday morning.
