Dr E. Ramanathan PhD
Cementitious Hybrid Acrylic Waterproof Coating – Two-Component Formulation
This system consists of a liquid polymer part (Part A) and a powder/cementitious part (Part B) mixed just before application.
🔹 Part A – Liquid Component (Acrylic Polymer Binder)
Here is the Part A – Liquid Component formulation of cementitious hybrid acrylic waterproof coating, scaled to 100% total weight:
Cementitious Coating Compound – Part A (100% w/w Basis)
| Ingredient | % by Weight (of Part A) | Function |
|---|---|---|
| Acrylic Emulsion (high solids) | 45–50% | Flexibility, adhesion, film former |
| Water | 30–35% | Viscosity adjustment |
| Coalescing Solvent (e.g., Texanol) | 1–2% | Film formation aid |
| Dispersing Agent | 0.3–0.5% | Pigment/filler dispersion |
| Defoamer | 0.2–0.3% | Foam control |
| Thickener (e.g., HEC or PU-based) | 0.5–1.0% | Rheology control |
| Anti-fungal/Anti-algal agent | 0.2–0.3% | Bio-resistance |
| Plasticizer (optional) | 0.5–1.0% | Flexibility improvement |
This formulation is used in 2K systems along with Part B (cementitious fillers).
Formula for Part A is revised for 100%
✅ Final: Part A for 100 kg batch
| Ingredient | Weight (kg) |
|---|---|
| Acrylic Emulsion | 55.62 |
| Water | 39.05 |
| Coalescing Solvent | 1.78 |
| Dispersing Agent | 0.47 |
| Defoamer | 0.36 |
| Thickener | 1.18 |
| Anti-fungal/Anti-algal agent | 0.36 |
| Plasticizer | 1.18 |
| Total | 100.00 |
Here is the complete 100% by weight formulation of Part A – Liquid Component for the cementitious hybrid acrylic waterproof coating:
This 100% by weight formulation can be used as-is when mixing with Part B (powder) in a 1:2 ratio.
🔹 Mixing Ratio (by weight)
- Part A : Part B = 1 : 2
- Mix with a slow-speed stirrer for 3–5 minutes to a lump-free paste.
🔹 Application
- Apply by brush or roller in 2–3 coats.
- DFT per coat: ~0.5–0.8 mm (wet).
- Recoat after 6–8 hours; full cure in 7 days.
- Coverage: ~1.5–2.0 m²/kg (for 2 coats).
🔹 Advantages
- Strong adhesion to concrete and masonry.
- Crack bridging ability (~1 mm).
- Excellent waterproofing under tile beds, in bathrooms, terraces, and retaining walls.
Cementitious Hybrid Acrylic Waterproofing – Reinforced Version with Geotextile & for Negative Side Waterproofing
This enhanced version includes geotextile mesh reinforcement between coats and is suitable for both positive and negative waterproofing (e.g., retaining walls, basements from the inner side).
🔹 System Components
✅ Part A – Liquid Polymer (Same as before)
(Use the same formulation previously given)
✅ Part B – Cementitious Powder (Slightly modified)
| Ingredient | % by Weight | Function |
|---|---|---|
| OPC 43/53 Grade Cement | 35–38% | Primary binder |
| Graded Silica Sand (fine) | 25–30% | Strength, shrinkage resistance |
| Microsilica/Silica Fume | 7–8% | Barrier effect, chemical resistance |
| Talc/Mica | 12–15% | Lamellar filler, waterproofing aid |
| RDP (Redispersible Polymer) | 2–3% | Crack bridging, flexibility |
| Fiber (e.g., PVA or Cellulose) | 0.5–1% | Micro-reinforcement |
| Hydrophobic additive (optional) | 0.5–1% | Additional water repellence |
🔹 Geotextile Mesh Reinforcement
- Type: Non-woven polyester or fiberglass mesh (~45–60 gsm)
- Purpose:
- Improves tensile strength
- Bridges substrate movement and microcracks
- Prevents delamination in critical areas (corners, joints)
Application:
- Apply first coat of mixed slurry (~0.8 mm wet).
- Immediately embed geotextile over wet coating.
- Smooth out air pockets using roller or trowel.
- Let it set for 4–6 hours.
- Apply second coat to fully sandwich the mesh.
🔹 Application Details (For Negative Side too)
| Parameter | Value |
|---|---|
| Mixing Ratio (Part A : B) | 1 : 2 (by weight) |
| Coating Thickness (total) | 1.5–2 mm (for both coats) |
| No. of Coats | 2 coats (with embedded geotextile) |
| Pot Life | 30–45 mins after mixing |
| Recoat Time | 6–8 hours |
| Full Cure | 5–7 days |
| Waterproofing Direction | Positive and Negative side suitable |
🔹 Recommended Areas of Use
- Underground water tanks (inside/outside)
- Basement walls (interior side = negative)
- Terraces and podiums (with or without tiling)
- Retaining walls, tunnels, lift pits
Bill of Materials (BOM) & SOP for Cementitious Hybrid Acrylic Waterproofing (with Geotextile Reinforcement)
🔹 1. Bill of Materials (Per 100 m² Coverage)
| Material | Quantity | Unit | Remarks |
|---|---|---|---|
| Acrylic Emulsion (Part A) | 40–45 kg | kg | High solids, elastomeric grade |
| Water (for dilution) | 25–30 liters | liters | Adjust for desired brushable consistency |
| Cement (OPC 43/53 Grade) | 70–75 kg | kg | Fresh, lump-free |
| Silica Sand (fine, 200–300 mesh) | 60–65 kg | kg | Graded and dried |
| Microsilica/Silica Fume | 12–15 kg | kg | Optional but recommended for barrier strength |
| Talc/Mica Powder | 25–30 kg | kg | Lamellar barrier property |
| Redispersible Polymer Powder | 3–5 kg | kg | Improves bonding and crack bridging |
| Fiber (Cellulose/PVA) | 0.5–1 kg | kg | Anti-crack micro reinforcement |
| Wetting & Dispersing Agent | 0.5–1 kg | kg | To be premixed in Part A |
| Thickener (HEC/ASE/PU) | 0.5–1 kg | kg | Rheology adjustment |
| Defoamer | 0.2–0.3 kg | kg | Foam control during mixing |
| Geotextile Mesh (nonwoven) | 105–110 m² | m² | Overlap margin included |
| Optional Additives | 0.5–1 kg each | kg | Algaecide, hydrophobe, etc. as needed |
🔹 2. SOP (Standard Operating Procedure)
Surface Preparation
- Clean surface: Remove dirt, grease, algae, efflorescence.
- Repair cracks (>0.5 mm) with polymer-modified mortar or crack filler.
- Dampen the surface lightly before coating (no standing water).
Mixing Instructions
- Part A: Stir emulsion + water + additives.
- Part B: Dry mix all powders (cement, fillers, RDP, silica, fibers).
- Slowly add Part B into Part A while stirring mechanically.
- Mix until lump-free, creamy consistency.
- Pot life: Use within 30–45 minutes.
Application (2–3 coats total)
| Step | Action |
|---|---|
| 1 | Apply first coat (~0.8 mm) with brush or roller. |
| 2 | While wet, embed geotextile mesh fully. |
| 3 | Smooth out wrinkles/air bubbles with roller. |
| 4 | Allow drying (6–8 hours). |
| 5 | Apply second coat to cover the mesh completely. |
| 6 | Optional third coat for exposed areas. |
Curing & Protection
- Allow full curing: 5–7 days.
- Light mist water curing may be done if very hot/dry.
- Protect from rain for 24 hours post-application.
