| Primary value | 100 mm total build-up (screed + WP + brick-bat coba + screed) |
| Applies to | RCC terrace slabs (residential and commercial buildings) · Sunken slabs in bathrooms and kitchens · Waterproofing systems before landscaping or photovoltaic install |
| Exceptions | APP / SBS bituminous membrane → 3 – 4 mm thick |
| Liquid-applied (PU / acrylic) → 1.5 – 2.0 mm DFT × 2 coats | |
| Brick-bat coba (traditional) → 75 – 100 mm overall | |
| Tank / underground waterproofing → Crystalline + 2-coat membrane | |
| Slope of substrate → 1 : 100 to 1 : 80 to outlets | |
| Measured as | Total height build-up from top of structural RCC slab to the protective wear-coat / final finish. Each layer measured perpendicular to the slab. |
| Source | IS 14215 / IS 7193 — Waterproofing systems ✓ Verified |
4 related items across IS codes, knowledge articles, design rules, maps and tools
Terrace waterproofing failure is the #1 source of building dampness complaints in India — 70% of damp-patch claims trace back to a flat terrace that didn't keep its slope or got punctured. The 100 mm system (screed + membrane + brick-bat + screed) provides redundancy: even if the membrane fails locally, the brick-bat coba's high-cement mortar layer holds back water.
Indian residential terraces typically use brick-bat coba at 75 mm + 25 mm IPS screed = 100 mm build-up over the slab. Modern projects swap brick-bat for APP membrane + 50 mm protective screed. Bathroom sunken slabs use liquid-applied PU at 1.5 mm DFT directly over slab + screed + tile.