If gardeners have a clear idea of how to build a gravel bed, the question of material requirements arises. Significant cost item in the budget is the required amount of gravel. If you scrimp at this point, you will be annoyed by the incomplete gravel cover. Too generous a calculation, on the other hand, drives up the costs unnecessarily. This guide explains how to correctly determine the gravel requirement.

The grain size is decisive for the amount

Grain size defines layer height for opaque gravel covering

General height information for the layer height in the gravel bed only serves as an initial orientation when determining requirements. If you are aiming for an opaque gravel surface, focus on the grain size of your favorite type of gravel. Act according to the following premise:

  • Rule of thumb: Optimum dumping height corresponds to twice the grain size

If you have chosen white quartz gravel with a grain size of 16-25 mm, apply the gravel at a height of 50 mm, i.e. 0.050 m. If you use Donoau gravel with a grain size of 8-16 mm, the fill height is 32 mm. i.e. 0.032 m.

Formula for material requirements - how to calculate correctly

So that you can calculate the required amount of gravel, first measure the bed. The bulk density per cubic meter of the selected type of gravel is missing as a third piece of information for the determination of requirements. This value is already part of the offer from building material suppliers or can be read on the Internet. The following formula gives the actual gravel requirement for your bed:

  • Length x width x double grain height x bulk density/m³

In order to cover a 5 m long and 4 m wide bed with 8-16 mm Danube gravel (1.42 t bulk density per m³) so that it is opaque, the following calculation results: 5 m x 4 m x 0.032 m x 1420 kg = 908.8 kg gravel requirement.

include delivery costs

To calculate the costs, first multiply the purchase price per kilogram of gravel by the required quantity. Added to this are the delivery costs, which can be significant given the considerable weight. Bargain foxes among the house gardeners rent a trailer and drive to the nearest gravel works.

tips

In order for the calculated amount of gravel to remain where it belongs, an adequate bed border must not be missing. Even a simple metal lawn edge prevents the stones from spreading in the garden. A border of natural stone sets the scene for the gravel bed in a decorative and tasteful way.

Category:

Garden design