Every column in the house sits on a footing, and the footings together are a significant first steel order. A clear method lets you check the schedule before the first lorry arrives.
Inputs (from the drawing)
| Item | Example |
|---|---|
| Footing | 1.5 × 1.5 m, isolated |
| Mesh | 12 mm @ 150 mm each way |
| Cover | 50 mm |
| End bends | 150 mm up at each end |
| Column | 230 × 300 mm, 6-12φ |
Footing Mesh
Bars per direction: (1,500 − 2 × 50) ÷ 150 + 1 = 9.33 + 1 → 11 bars (rounding up)
Length of one bar: 1.5 − 2 × 0.05 + 2 × 0.15 = 1.7 m
Both directions: 22 bars × 1.7 m = 37.4 m
Weight: 37.4 × 0.888 = 33.2 kg
Column Starter Bars
Starter bars rise from the footing to lap with the column:
- Length ≈ bend at the bottom (say 0.3 m) + footing depth to top (say 0.6 m) + column neck to plinth (say 1.0 m) + lap (0.6 m) ≈ 2.5 m
- 6 bars × 2.5 m × 0.888 = 13.3 kg
- Ties along the column neck as per drawing
Footing Totals
| Part | Weight |
|---|---|
| Mesh (both ways) | 33.2 kg |
| Starter bars | 13.3 kg |
| Neck ties | from drawing |
| Approx. per footing | ≈ 47 kg + ties |
Multiply by the number of footings of each type. A G+1 house with 12–16 footings needs several hundred kilograms in its foundation.
The Short Version
Bars each way from width, spacing and cover; length from size, cover and bends; weight from the chart. Add starter bars, multiply by the footing count, and add a few percent for cutting.
