Waterproofing materials and methods for Indian construction per IS 3067:1988. Covers integral waterproofing compounds, surface coatings, sheet membrane systems, and injection grouting. Selection depends on hydrostatic pressure, substrate type, accessibility for maintenance, and exposure conditions. All thicknesses and coverage rates are indicative — follow manufacturer specifications for the specific product.
Surface Applied (Coatings)
Applied on the positive (water-facing) or negative side of the substrate. Substrate must be clean, damp (not wet), and free of oil/loose material.
| Material | Type | Application | Thickness | Life |
|---|
| Polymer-Modified Cementitious Coating | Acrylic/SBR modified cement slurry | Terrace, bathroom, water tank interior, balcony | 2 coats × 1 mm each = 2 mm total | 10–15 years |
| Bituminous Coating (cold-applied) | Solvent-based or emulsion bitumen | Basement walls (external), foundation, plinth | 2 coats × 0.5 mm = 1 mm total; 1.2–1.5 kg/m² coverage | 10–20 years |
| Polyurethane (PU) Liquid Membrane | Single/two-component PU coating | Terrace, podium deck, exposed roof, balcony, parking deck | 1.0–1.5 mm (applied in 2–3 coats) | 8–12 years |
| Acrylic Elastomeric Coating | Water-based acrylic polymer | External walls, terrace (light traffic), parapet | 0.3–0.5 mm (3–4 coats) | 5–8 years |
| Epoxy Coating | Two-component epoxy resin | Water tank interior, STP, chemical containment, basement floor | 0.3–0.5 mm (2 coats) | 15–20 years |
| Silicone Water Repellent (surface impregnation) | Silane/siloxane solution | External exposed concrete, stone cladding, brick facade | Penetrates 2–5 mm into substrate (no film) | 5–10 years |
Membrane Systems
Pre-formed sheets applied with heat, adhesive, or mechanical fixing. Provide continuous barrier. Joints must have minimum 100 mm overlap.
| Material | Type | Application | Thickness | Life |
|---|
| APP Modified Bituminous Membrane | Atactic Polypropylene modified bitumen sheet | Terrace, podium, planter box, split-level sunken area | 3–4 mm single layer or 2×2 mm double layer | 15–20 years |
| SBS Modified Bituminous Membrane | Styrene-Butadiene-Styrene modified bitumen sheet | Basement, terrace, expansion joints, cold regions | 3–4 mm | 15–25 years |
| HDPE Sheet Membrane | High-density polyethylene sheet | Basement raft, retaining wall (external), landfill liner | 0.5–2.0 mm | 50+ years |
| PVC Membrane | Plasticized polyvinyl chloride sheet | Tunnel, basement, water feature, green roof | 1.2–2.0 mm | 25–30 years |
| Bentonite Sheet / Geosynthetic Clay Liner (GCL) | Sodium bentonite between geotextile layers | Basement slab (blind side), pile caps, below-grade walls | 5–6 mm (swells to 15–20 mm when hydrated) | Life of structure |
| Self-Adhesive Bituminous Membrane | Cold-applied peel-and-stick membrane | Bathroom, kitchen, balcony, small terrace areas | 1.0–1.5 mm | 10–15 years |
Notes
• IS 3067 Cl. 4.1: Waterproofing is most effective when applied on the positive side (water-facing side) — negative-side application is remedial only
• Substrate preparation is critical: surface must be free of oil, grease, curing compound, laitance, and loose particles. Use wire brush or water jetting to expose sound concrete
• For membrane systems, lap joints must be minimum 100 mm (150 mm for bentonite); stagger T-joints. All laps must be in the direction of water flow
• Curing of cementitious coatings: keep moist for 3–7 days by water spraying or damp hessian. Do not allow to dry within 24 hours of application
• For terrace waterproofing, always provide screed with slope (1:100 to 1:120) towards outlets before applying membrane or coating
• All pipe penetrations, drain outlets, and parapet junctions need 150 mm coved fillets and reinforced treatment with extra membrane strip or coating layer
• Protection layer (screed or geotextile) must be provided over membrane before backfilling or laying tiles — membrane puncture is the #1 failure cause
• In bathrooms, waterproofing must extend 150 mm above finished floor level on all walls, and full height (2.1 m) on shower walls per NBC 2016
• Primer is mandatory before bituminous membrane/coating application — use bitumen primer IS 3384 at 0.2–0.3 L/m² and allow 4–6 hours drying
• Do not apply waterproofing coatings on surfaces with rising dampness — first arrest the source, then apply after substrate is only damp (not wet)