ᐅ Calculation of Topsoil and Fill Sand Volume for a Sand Slab Foundation

Hello!

We are having a dispute with a company that installed the sand slab.
The work area was 14 x 15.5 m (217 sqm).
The installed sand slab had an average thickness of about 30-35 cm (12-14 inches), and the topsoil was removed to the same depth.

The questions are:
- How much topsoil needs to be hauled away?
- How much fill sand needs to be delivered and installed?
- What volume changes can be expected for the topsoil and the fill sand?

Thank you in advance for any insights.

Best regards,
Stefan

PS: I hope this is the right place for this question

What is the disagreement about?
It depends on how the billing is done and what is specified in the quote / bill of quantities.
It can be based on square meters, cubic meters, or tonnage...
Topsoil is often billed by square meters, disposal by tons, and subgrade by square meters or cubic meters.

The billing was made based on sqm for removing the topsoil and on cbm for installing the filling sand and transporting the topsoil away.

From the contractor’s side, contradictory figures have been presented in my view.

Actually, no.
Topsoil area: 217 m² (2,335 sq ft)
He will only know how much he needs to move once it’s removed.
The installation depends on how much he has moved; at 35 cm (14 inches), that would be 76 m³ (2,684 cubic feet).
There might be some debate about the removal of the topsoil. Usually, it would be weighed, but it probably won’t cost anything anyway since it will be resold and not disposed of.

Yes, but it should be mentioned that the first time he said he installed 250 cubic meters (cbm) of fill sand and removed 140 cubic meters (cbm) of topsoil.

I doubted these figures, so he corrected them to 210 cubic meters (cbm) of fill sand and 120 cubic meters (cbm) of topsoil.

It should also be noted that the contractor was instructed to remove a maximum of half of the material.

If the solid native soil is loosened, you can add another one-third to the volume. However, any coverings used for weighing should be included.

Were the 14 x 15 m (46 x 49 feet) the dimensions of the work area or of the foundation?