Single-family house with a ground-level granny flat on a slope

Unfortunately, that's not possible yet. But it doesn't matter. It's better if the forum benefits from it anyway. You'll also get a third opinion there.

I generally think it's good to consider the readers. But you can still exchange your contact details: if both are online, 1. mention the other in the post with @ so they see a notification, and write down your contact details, then 2. during the edit window, remove the contact details - and voilà, the other has seen them but only very few third parties have, so you avoid getting a spam avalanche.

Hello everyone,

quick update: the conversation with Lechner Massivhaus was okay, a typical sales talk in a pleasant atmosphere – we’ll meet again in 2 weeks.

No new insights, except maybe that a garage under the house is more expensive than a basement – apparently everything has to be insulated differently and you also have to dampen the vibrations caused by the car in the house. I was told that it’s six of one, half a dozen of the other, what goes under the house if it’s just a utility basement.

Can anyone confirm that?

We’ll still ponder a bit today to see how we can optimize it. I’ll come back to the points mentioned above later.
See you later

and you also have to dampen the vibrations that the car causes inside the house.

Corvette ... Abarth ... ? - with the damn Daimler nothing vibrates.

So it's nonsense that the (prefabricated) garage under the house costs more than the (prefabricated) basement? Because then it might be smarter to leave out the garage entirely, instead there would be parking spaces to the east next to the houses and you could get from the parking spaces to the north-facing entrance doors via a few stairs.

Why even plan a garage or utility cellar/storage room on one floor? Why not a residential basement?

I wanted to or I suggested it. But they just said that they have to calculate whether it’s even worth it, because a full basement is way too expensive and not necessary. The idea with the garage in the east and the entrances in the north came to me on the way back, so I couldn’t mention it.

In 2 weeks I’ll know what they have come up with. Apparently, they are very experienced with hillside properties and even though mine is challenging, they are confident that they will find a great solution.

The expanded clay walls are interesting. But I don’t know if they are really that good without insulation.

according to it’s also not true that garages under the house are so expensive because everything vibrates ‍♂️