Choose component volumes over an unweighted average thickness.
When does averaging several thicknesses misstate a concrete quantity?
Use the matching calculator
Use this decision sequence
- Separate regions whose thicknesses differ and measure their non-overlapping areas.
- Multiply each region area by its own specified thickness.
- Add the resulting volumes, or calculate an area-weighted mean thickness.
- Use a simple endpoint average only for a region with a stated linear taper.
Keep the quantities distinct
| Quantity or assumption | How to use it |
|---|---|
| Equal region areas | A simple mean of their depths can work. |
| Unequal areas | Require area weighting. |
| Linear taper over one region | Uses the average endpoint depth on that region. |
Worked comparison
A 9 m² region at 0.1 m thickness and a 1 m² region at 0.3 m need 0.9 + 0.3 = 1.2 m³. An unweighted mean depth of 0.2 m applied to all 10 m² incorrectly gives 2 m³. The correct area-weighted mean is 1.2/10 = 0.12 m. Neither averaging method selects the construction depths themselves.
Check before using the estimate
Avoid overlaps between regions, and use measured or already specified depths rather than invented generic values.
All dimensions, product properties, prices and specifications in this example are illustrative arithmetic inputs. Use the values from your measured plan, selected product data sheet and supplier quote. This guide does not choose construction specifications or certify safety.
Calculation and scope checked 2026-10-04. Methods and scope.
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