Hourdis Floor Weight Calculator

How to Use This Calculator

This free hourdis floor weight calculator helps builders, architects and DIY enthusiasts quickly estimate the total weight of a hollow-core concrete floor slab. To use it, simply enter the span (distance between supports) in meters, the center-to-center spacing of the joists in meters, and the slab thickness in centimeters. Click calculate, and you'll get an approximate weight in kilograms.

Formula and Methodology

The calculation is based on a simplified volumetric approach: weight = span × spacing × thickness (converted to m) × density factor × 2500 kg/m³. The density factor of 0.25 accounts for the hollow cavities in the blocks. This gives a quick estimate suitable for preliminary sizing, transportation planning, or material cost estimation.

Practical Examples

Suppose you have a bay of 5 m span, 0.6 m spacing, and 20 cm slab thickness. The calculator multiplies: 5 × 0.6 × 20 × 0.25 × 2500 = 37,500 kg. That's the total weight for that area. For a smaller room, 4 m span, 0.5 m spacing, and 16 cm thickness: 4 × 0.5 × 16 × 0.25 × 2500 = 20,000 kg.

Tips and Best Practices

Always use consistent units: meters for lengths, centimeters for thickness. For higher accuracy, adjust the density factor (0.20-0.30) depending on block type. This tool is for estimation only — final design requires a structural engineer. Keep a safety margin for live loads and finishes.