List of incidental construction costs. More expensive "on the builder's side"?

We had an amount x as a buffer in the calculation. And I know what became more expensive and the buffer is now gone.

we had an amount x as a buffer in the calculation. And I know what got more expensive and the buffer is gone now.

What was it?

we were also allowed to dispose of soil for many thousands of euros. And we also have to make adjustments. The flooring is just blowing the budget. I think I have the wrong profession.

we had an amount x as a buffer in the calculation. And I know what got more expensive and the buffer is now gone.

The buffer was gone for us with the extended earthworks and later removal.

So pretty much at the beginning.
However, we rounded up generously everywhere and added another 10%. That's how we managed.

But what I’m reading here again, everything is tight and 10% is not mentioned at all, then terrace and paving in EL (material costs nothing) and the kitchen doesn't appear anywhere either, that won’t work!!!

What was it then?

15,000€
Now it's gone.
Everything is getting more expensive. But now everything is done.
E.g. civil engineering (excavating, disposing, filling and gravel etc.)
1st offer was 55,000€
2nd offer 38,000, 3rd 14,000
Then commissioned the "cheapest", paid over 19,000€
Calculated were 15,000€
So almost 5,000€ of the buffer already gone...

But what I’m reading here again, everything tight and 10% is not mentioned at all, then terrace and paving in EL (material costs nothing) and the kitchen also doesn’t appear anywhere, that won’t work!!!

Are 10% enough overall? I dare to doubt it. Given the expectations of the participants here. But yes, it is achievable, you have to restrain yourself.