Types of Wall Cracks
| Crack Type | Appearance | Severity | Cause |
|---|---|---|---|
| Hairline cracks | Very fine, <0.5mm | Low — cosmetic | Plaster shrinkage, thermal movement |
| Settlement cracks | Diagonal at corners | Medium | Differential foundation settlement |
| Structural cracks | Wide, through-wall | High — urgent | Foundation failure, overloading |
| Moisture cracks | Irregular, damp patches | Medium | Water ingress, leakage |
Most Common Causes in Kolkata Homes
- Poor curing: Cement plaster must be cured with water for minimum 7 days. Skipping this causes shrinkage cracks as the plaster dries too fast.
- Foundation issues: Kolkata’s soft soil requires proper foundation design. Inadequate depth or width causes settlement cracks.
- Thermal expansion: Temperature changes cause walls to expand and contract. This is normal but must be accommodated with control joints in long walls.
- Substandard materials: Excessive water in concrete (high water-cement ratio) causes cracking on setting. Always follow mix ratios.
- Overloading: Placing heavy loads (water tanks, AC units) on walls not designed for them can cause structural cracking.
Prevention Checklist
- ✅ Soil test before foundation design
- ✅ Proper concrete mix ratios (do not add excess water)
- ✅ 7-day wet curing of all plaster and concrete
- ✅ Control joints in walls longer than 6 metres
- ✅ Waterproof parapet walls to prevent water entry
- ✅ Use only verified quality cement and aggregates
Source Quality Materials to Prevent Defects
Substandard materials are the root cause of most construction defects. Buy from verified dealers.