Foundation Material & Depth Calculator
Generate a precise shopping list for concrete foundations. Calculates cement bags, sand, aggregate, and rebar length with waste margins.
About
Estimating materials for a foundation pour is a logistical challenge where errors are costly. Ordering too little concrete leads to "cold joints" (structural weaknesses where fresh concrete meets hardened concrete), while ordering too much wastes budget and creates disposal issues. Similarly, steel reinforcement (rebar) must be procured in precise lengths to account for grid spacing and overlaps.
This calculator determines the exact volume of concrete required for Strip or Slab foundations and breaks it down into raw materials (Cement, Sand, Aggregate) based on standard M300 (C20/25) mix ratios. It also generates a procurement list for rebar based on standard grid configurations.
Formulas
The calculator uses the volumetric method converting total required volume ($V_{total}$) into mass components using specific density and mix proportions. A waste margin ($w$) is applied to the final sum.
1. Total Volume with Waste:
Vreq = (L × W × D) × (1 + w)2. Component Mass (Cement Example):
Mcement = Vreq × Ratiocem∑ Ratios × DensitycemReference Data
| Material | Density (kg/m³) | Standard Mix Ratio (M300) |
|---|---|---|
| Cement (Portland) | 1440 | 1 Part |
| Sand (Fine Aggregate) | 1600 | 2.4 Parts |
| Gravel (Coarse Agg.) | 1500 | 4.1 Parts |
| Water | 1000 | 0.6 Parts |
| Steel Rebar | 7850 | Grid Spacing (20 cm) |