Sand Cement Screed Calculator Square Feet

Screed Mix Formulas:

\[ \text{Cement (lb)} = \left[\text{Area (ft²)} \times \text{Thickness (ft)} \times 1.33 \times \left(\frac{1}{1 + \text{ratio}}\right)\right] \times 90 \] \[ \text{Sand (lb)} = \left[\text{Area} \times \text{Thickness} \times 1.33 \times \left(\frac{\text{ratio}}{1 + \text{ratio}}\right)\right] \times 100 \]

Cement Required:

Sand Required:

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1. What is Sand Cement Screed?

Sand cement screed is a mixture of sand, cement, and water used to create a level surface on floors before applying final floor coverings. The ratio of sand to cement determines the strength and workability of the screed.

2. How Does the Calculator Work?

The calculator uses these formulas:

\[ \text{Cement (lb)} = \left[\text{Area} \times \text{Thickness} \times 1.33 \times \left(\frac{1}{1 + \text{ratio}}\right)\right] \times 90 \] \[ \text{Sand (lb)} = \left[\text{Area} \times \text{Thickness} \times 1.33 \times \left(\frac{\text{ratio}}{1 + \text{ratio}}\right)\right] \times 100 \]

Where:

1.33 — Compaction factor for screed
90 — Weight multiplier for cement (lb per cubic foot)
100 — Weight multiplier for sand (lb per cubic foot)
ratio — Sand to cement ratio (e.g., 4 for 1:4 mix)

Explanation: The formulas calculate the volume of screed needed and then determine the quantities of cement and sand based on the specified ratio.

3. Importance of Proper Mix Ratio

Details: The sand-cement ratio affects the screed's strength, durability, and workability. Common ratios range from 1:3 (strongest) to 1:5 (weaker but more economical).

4. Using the Calculator

Tips: Enter area in square feet, thickness in feet, and ratio as a single number (e.g., enter 4 for 1:4 ratio). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical screed thickness?
A: Most floor screeds are 2-4 inches (0.17-0.33 feet) thick, depending on application and substrate conditions.

Q2: What does 1:4 ratio mean?
A: It means 1 part cement to 4 parts sand by volume (not weight). This is a common ratio for floor screeds.

Q3: Why is there a compaction factor?
A: The 1.33 factor accounts for compaction and voids in the mixed material to ensure you have enough screed.

Q4: Can I use this for exterior applications?
A: This calculator is primarily for interior floor screeds. Exterior applications may require different mixes.

Q5: How much water should I add?
A: Water content varies, but typically 4-5 liters per 50kg cement bag. The mix should be workable but not soupy.