10 smart ways to keep your house slab (roof) cool and waterproof, especially useful in hot and rainy areas along with approximate costs in 2025 (India)
1. Apply White Reflective Coating (Cool Roof Paint)
Why: Reflects sunlight, reduces heat absorption.
Cost: ₹30–₹60/sqft
Popular brands: Dr. Fixit Heat Shield, Asian Paints SmartCare Heat Reflector
2. Install Thermal Insulation Sheets (XPS or PU Boards)
Why: Reduces heat transfer through the slab.
Cost: ₹80–₹150/sqft (including installation)
3. Use China Mosaic or White Glazed Tiles
Why: Reflects sunlight and provides water drainage.
Cost: ₹60–₹100/sqft
4. Apply Liquid Waterproofing Membrane
Why: Seals cracks and prevents water leakage.
Cost: ₹40–₹80/sqft
Brands: Fosroc Brushbond, Sika, Dr. Fixit Newcoat
5. Use Green Roof (Roof Garden)
Why: Natural insulation and aesthetic look.
Cost: ₹150–₹300/sqft (including soil, waterproofing, drainage layer)
6. Place Cool Roof Panels (Overdeck Insulation Sheets)
Why: Keeps slab cooler and waterproofed from top.
Cost: ₹120–₹200/sqft
7. Build a False Ceiling with Insulation (Underdeck Treatment)
Why: Reduces internal heat even if slab is hot.
Cost: ₹100–₹200/sqft
8. Use Mud Phuska (Traditional Method)
Why: Low-cost insulation and waterproofing.
Cost: ₹25–₹40/sqft
Tip: Needs regular maintenance but very effective in rural/low-budget setups.
10. Install Solar Panels
Why: Absorbs sunlight for power and provides shade to slab.
Cost: ₹70,000–₹1,00,000 (for 1kW system, 100 sqft area approx.)
Bonus: Saves electricity and reduces slab temperature underneath.