Post and lintel construction is an old and familiar method, even if you have never heard of it. If you have seen a picture of the Parthenon, in ancient Greece, you have seen post and lintel construction. It is based on solid, upright columns (posts) that are topped by horizontal beams (lintels). If you are setting a concrete lintel in your project and want to figure out how much concrete you need, use your plans to get a good idea of the lintel volume.
Note the width, height and length of the lintel on your blueprint, if those figures are not spelt out already.
Convert the measurements by multiplying them according to the drawing scale. For instance, if the scale is 1:100, 1 cm on the plan represents 1 m in the real building.
Multiply the converted measurements together to find the total volume. For example, if the lintel is to be 1 m (40 inches) long, 30 cm (1 foot) wide and 30 cm (1 foot) high, the volume would be 0.09 cubic metres (3.17 cubic feet).
If you would like to convert your volume from cubic metres to litres, multiply the number of cubic metres by 1000. In this example 0.09 cubic metres becomes 90 litres.