New basement under the foundation of an existing house

Hello everyone,
I am here and have a feasibility question. It concerns a house that already has a basement and a foundation about 1 meter thick. The house was built in 1964. My question is now, would it be possible, under this building, more precisely under the foundation (which I estimate to be a better option than breaking up the foundation), to expand the basement, possibly with two floors underground. Adjacent at the back is a lot of green space and behind it houses that also belong to us and are rented out. If this is possible, how do you estimate the costs?

If this is possible, how do you estimate the costs?

Everything is possible. Financially reasonable? Certainly not...

I had already expected that, but still out of interest, how much additional cost would it be compared to if I were to basement the green area on the Huntereb part of the house instead, up to the edge of the house (that is, per m^2)?

So you don't want to cellar the existing house but rather build a basement as an extension? Why not an above-ground extension?

How are you supposed to give an estimate if you have no information? Groundwater? Soil class? Area? Use of the basement?

But just if you dig deeper than the existing basic structure, you have to underpin the old structure. That alone will already cost a lot (the deeper you build new, the more expensive the underpinning). But no one here can give an estimate for that either.

So I think if you get a number here, it is wrong.

Best regards

I am here and I have a feasibility question right away. It is about a house that already has a basement and a foundation about 1 meter thick. The house was built in 1964. My question now is, would it be possible to expand the basement under this building, more precisely under the foundation (which I estimate is the better option than tearing up the foundation), possibly with two underground levels. Adjacent at the back is a large green area and behind that are houses that also belong to us and are rented out.

A foundation one meter thick does not bode well for a trouble-free subsoil. But now - with a horizontal drilling, FlowTex, anyone? - a two-story (second and third) basement is supposed to be inserted under the building, even extending beyond its footprint. No further honors, your questions (or whatever it’s called) – to me this sounds like a fake alarm of the highest order. A humor section has been missing here so far, thanks for that!