Sand and Cement Calculator for Screed Board

Screed Mix Formula:

\[ \text{Cement (kg)} = \left[\text{Area (m²)} \times \text{Thickness (m)} \times 1.33 \times \left(\frac{1}{1 + \text{ratio}}\right)\right] \times 1440 \] \[ \text{Sand (kg)} = \left[\text{Area} \times \text{Thickness} \times 1.33 \times \left(\frac{\text{ratio}}{1 + \text{ratio}}\right)\right] \times 1600 \]

Cement Required:

Sand Required:

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1. What is Screed Board Mix?

Screed board mix is a combination of cement and sand used to create a smooth, level surface for flooring. The ratio of cement to sand affects the strength and workability of the screed.

2. How Does the Calculator Work?

The calculator uses these formulas:

\[ \text{Cement (kg)} = \left[\text{Area} \times \text{Thickness} \times 1.33 \times \left(\frac{1}{1 + \text{ratio}}\right)\right] \times 1440 \] \[ \text{Sand (kg)} = \left[\text{Area} \times \text{Thickness} \times 1.33 \times \left(\frac{\text{ratio}}{1 + \text{ratio}}\right)\right] \times 1600 \]

Where:

Area — Surface area to be covered (m²)
Thickness — Depth of screed layer (meters)
Ratio — Cement to sand ratio (e.g., 1:4 = 4)
1.33 — Factor accounting for compaction and waste
1440 — Density of cement (kg/m³)
1600 — Density of sand (kg/m³)

3. Importance of Correct Mix Ratio

Details: The right cement-sand ratio ensures proper strength, durability, and workability. Common ratios range from 1:3 (stronger) to 1:5 (more economical).

4. Using the Calculator

Tips: Measure area accurately in square meters. For thickness, typical screed is 50-75mm (0.05-0.075m). The ratio should match your project requirements.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical screed mix ratio?
A: Common ratios are 1:3 to 1:5 (cement:sand). 1:4 is often used for general purposes.

Q2: Why multiply by 1.33?
A: This accounts for material compaction during installation and about 25% extra for wastage.

Q3: How thick should screed be?
A: Typically 50-75mm for domestic, 75-100mm for commercial. Minimum 25mm for bonded screeds.

Q4: Can I add additives?
A: Yes, plasticizers or fibers can be added to improve workability or reduce cracking.

Q5: How long does screed take to dry?
A: Typically 1 day per mm for the first 40mm, then 2 days per mm thereafter (about 4-6 weeks total).