Floor plan optimization for new construction, single-family house with 2 full floors without basement on a slope

The client expressed a wish, the company implements it directly?

Especially a "finished" house company can comfortably retreat to the "because I’m a little sheepie" position here, "not being able to do a basement" and leaving it up to the client, with a construction contract in hand, to "deliver" the plot in the state of a "finished reported base slab." It goes without saying that the client will request and review offers from civil engineers until any price guarantee retires. In this respect, I assume the answer to

Who ultimately planted the expensive idea in your head?

will probably be quite simply: "someone who benefits from the fact that the client dreams of a basement that can be saved here."

Nice that quite a few people have joined the thread by now. Thank you for your interest and willingness to help.

I guess I will have to provide some more information about the property after all. I thought it would be more about the floor plans and that this information would only overload things. But well. Now it is necessary.

The area is a very small new development with few plots. These are sold by the prefabricated house manufacturer, so we are buying the house and the plot from one company. Why are we doing this? Firstly, we trust the company, it is not a "cheap company" in terms of prefabricated house construction. Secondly, in the region where we want to build (as close to Kassel as possible) there are hardly any other plots available for purchase. Therefore, we see this plot as a lucky coincidence that we were at the right place at the right time. By now, all plots are sold out and we are still glad – although we have/had concerns regarding the hillside location/costs – that we bought one of the plots.

About the plot/house:
One problem is, among other things, that the street (purple line in the attachment – green line: existing terrain) is about 1 meter higher compared to the current terrain. We discussed the possibilities of a basement with the company. The costs were about 80k more expensive compared to the current offer. Another option, to enter the house via the upper floor and build the lower floor into the hillside, we rejected for several reasons. 1. About half of the rooms in the lower floor would have no daylight as they would be built into the hillside. 2. You would have to go upstairs to the ground floor after entering the house in order to get to the kitchen/living areas. 3. The ground floor could not have been built in timber frame construction in that case. The exterior walls would have been 17 cm thicker each. That would have cost living space and would also have been more expensive again.

You are of course right when you say that the incidental construction costs will be high. We are only budgeting about 60k for the earthworks by the civil engineer.

Hope I could clarify the situation a bit and I am curious whether you still see better possibilities to build the house with the info about the street.

The costs were about 80k more expensive compared to the current offer.

Another option is to enter the house through the upper floor and build the basement into the slope,

We are only calculating about 60k for the earthworks by the civil engineer.

Ultimately, there are 3 options, where the costs affect the benefit and comfort. …… From where to where exactly is the slope now? Only from north to south?

Where exactly is the slope now? Only from north to south?

Exactly. It is basically an inclined plane that slopes down 3m from north to south. There is no gradient from east to west.

Price estimate according to architect/planner: €390,000 (KFW40+ house)
Personal price limit for the house, incl. equipment: €450,000

Your price limit does not include additional construction costs, right? If you then estimate the earthworks at €60,000, plus the remaining additional costs at about €30,000, you end up at €480,000. On top of that, property transfer tax on the land AND house, furniture, kitchen, external facilities. I estimate that in the end you will come to about €560,000 - €600,000.

Your price limit is without ancillary construction costs, right? If you estimate the earthworks at €60,000, plus the remaining ancillary costs of about €30,000, then you’re at €480,000. Plus real estate transfer tax on the plot AND house, furniture, kitchen, outdoor facilities. I estimate you will end up at around €560,000 - €600,000.

Yes, correct. We even come out higher. More like €650,000-700,000 according to our calculation.