Limewash Calculator — Lime Putty, Water & Casein
Calculate limewash quantities for heritage and lime-rendered buildings. Covers 4-6 thin coats with lime putty:water ratios and casein for exteriors.
Total area to limewash
Casein improves weather resistance
How We Calculate This
This calculator determines limewash quantities for heritage buildings and lime-rendered walls. Limewash requires multiple thin coats rather than thick applications.
The formula
Limewash per coat (L) = Wall area × Coverage rate (L/m²) × Wastage
Total limewash = Litres per coat × Number of coats
Lime putty (kg) = Total litres × 0.5 kg/L
Casein (exterior) = Total litres × 0.02 kg/L
For example, 40 m² exterior lime render with 5 coats at 0.20 L/m²: Per coat = 40 × 0.20 = 8 L. Total = 8 × 5 = 40 L + 15% waste = 46 L. Lime putty = 46 × 0.5 = 23 kg. Casein = 46 × 0.02 = 0.92 kg.
Frequently Asked Questions
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Last updated: March 2026
All calculations are estimates. Verify with your supplier.