Fill the plot or wait?

We bought a plot of land and need to build an extension onto an existing semi-detached house. The neighbor has a basement, but we would build without a basement.

The semi-detached house should be 7m wide and 12m long. I measured that we are 60cm below his floor slab (street level). 2-3 meters further there is a slope (edge), where it will be about 80-90cm.

The neighbor told me during measuring that we would need a frost apron.

Now to my question:

We do not yet have a building permit, nor a soil report. Is it sensible to have the plot filled beforehand? Is it even necessary to have it filled? Because of the excavation pit, frost protection, etc.?

I will take pictures in the next few days. Thanks already.
Best regards

Before no expert report has been made and the height situation has been recorded by surveyors and architect/civil engineer and planned accordingly to the conditions, I wouldn't do anything there... not that in the end you have to get rid of filled soil because it was not needed at all and then it is in the way.

First the land, then the house plan, then once everything is clarified, then act or possibly not act.

First land, then house plan, then once everything is clarified, then act or possibly not act.

I don't think the land can be that bad. Next door there is already a semi-detached house. But the devil is in the details ‍♂️ I think I'll have one made in the next few days.

He definitely won't be that bad. Just try to find a construction contractor who starts without a soil report. Nowadays, everyone is too scared.

He certainly won't be that bad. Just try finding a contractor who starts without a soil report. These days everyone is so scared.

Hammmmaaaaa
Rarely laughed so hard sober on a Saturday evening

Most contractors already include that in their construction service.
Hope they accept it then too.