1. What is Sand and Cement Rendering?

Sand and cement rendering is the process of applying a mixture of sand, cement, and water to exterior or interior walls to create a smooth or textured surface. The ratio of sand to cement is crucial for the strength and durability of the render.

2. How Does the Calculator Work?

The calculator uses these formulas:

Where:

• Area — Surface area to be rendered in square meters
• Thickness — Render thickness in meters (typically 0.01–0.02 m)
• Ratio — Sand to cement ratio (e.g., 4 for 4:1 mix)
• 1.33 — Factor accounting for material compaction
• 1440 — Density of cement in kg/m³
• 1600 — Density of sand in kg/m³

3. Importance of Proper Mixing

Details: The correct sand-cement ratio ensures proper adhesion, durability, and workability. Common ratios range from 3:1 to 6:1 depending on application and desired finish.

4. Using the Calculator

Tips: Measure your wall area accurately. Typical render thickness is 15-20mm (0.015-0.020m). Standard mix ratios are 4:1 or 5:1 for general purposes.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical sand:cement ratio for rendering?
A: For most applications, 4:1 or 5:1 is common. 3:1 for stronger mixes, 6:1 for more permeable renders.

Q2: How much water should I add?
A: Enough to achieve a workable consistency - typically about 1 part water to 5 parts total dry materials.

Q3: Should I use building sand or sharp sand?
A: Building sand (soft sand) is typically used for rendering as it provides a smoother finish.

Q4: How long does render take to dry?
A: Initial set in 24-48 hours, full cure in about 28 days depending on conditions.

Q5: Can I add lime to the mix?
A: Yes, lime improves workability and flexibility. A common mix is 1 cement : 1 lime : 6 sand.