Foundation: Volume estimation for backfill gravel in single-family houses

Hello,

we received a craftsman's invoice for the foundation of a non-basement single-family house a year ago. Before the last installment to the construction company, I am reviewing all major invoices according to the Pareto principle.

Approximate dimensions:
Foundation area: 10 x 10 m
Depth: 30 cm
Elevation of the plot and necessary filling gravel: approx. 20 cm height

What volume in cbm would be roughly expected? I would first like to hear your estimate before I mention the number on the invoice. At least, by my calculation method, I come up with an amount that would be enough for half a party bunker.

The cbm specification for the topsoil would probably be quite comparable for an absolutely flat plot in northern Germany.

What is this "Guess with Rosenthal" game supposed to be? Just write what is on the invoice, then you will get opinions.

And remember, if a foundation is supposed to be 10x10 m, then a larger area is affected for processing.

You always need much more than you think. Workspace and allowances have already been mentioned, compacting also costs about 15% volume. Your property is probably not as level as you think. Are you also sure that the gravel was only used for the foundation? Usually, at this stage of work, things like crane area and construction road are also done.

Guessing game cool :cool:, 10x10m base plate, with working area 13x13m =169mx3, 0.8 deep for frost protection + 0.2 height =1m, +15% compaction losses, So 195mx3 is appropriate as my guess contribution

And where is the solution?
Unfortunately, my crystal ball is in for repair ...

And where is the solution? Unfortunately, my crystal ball is in repair ...

The solution will come as soon as I know the settlement between the construction company and the civil engineering company. They are currently keeping silent; no company wants to hand over the planning data. That is why the final payment is currently being withheld.

The flat rate price already included the foundation with all associated work. The civil engineering company was only supposed to provide extra service for the elevation of the property. The cubic meter figures in the invoice are about 2.5 times the calculation method shown here.