We know what we want, only the question is whether a basement fits within the budget.
So you know how you will build, which materials are needed in which quantities. What heating system with which specification is required. Which electrical installation with the number of switches, light outlets, sockets, network, etc. is desired. Complete tiling and floor coverings are clear. And so on. That is actually the task of the tender. If you can do everything yourselves, then all is well. My respect for that, I could not precisely name about 500 items and provide alternative options. Then you can specifically inquire and will receive comparable prices.
We have already written a list with points such as KFW 40+ Roof insulation Staircase design oak Wood-aluminum windows Living-dining area with venetian blinds (rest electric shutters) Air-water heat pump
It is comparable to ordering a car: Car Euro 6 Roof with sunroof Seats with fabric Windows with thermal insulation Electrically operated windows Diesel engine ==> What does the car cost with exactly these specifications from different manufacturers?
We didn’t get any quotes at all, work costs money, and it can always be cheaper, but usually it’s shoddy work, if you know the craftsmen like I have for years we only asked a max of 2, done. We didn’t have time to compare for long and in the end they were all similar.
We waived KfW40 immediately because the additional costs that have to be invested to get the subsidy did not stand in any relation for us.
We know what we want, the question is only whether a basement is within the budget. That's why the two options
I know we're drifting away from the original question, but building a house is a bit more complex. Do you have a floor plan once with and once without a basement? You don't just simply put a basement under a floor plan and that's it. At least on the ground floor, the layout and size of the rooms are then different... With a basement, the ground floor/upper floor might be a bit smaller or instead of 2 gables only 1 gable... and so on and so forth...
What is now important so that the offers we receive are as comparable as possible? We have already written a list with points such as KFW 40+ Roof insulation Staircase design oak Windows wood aluminum Living-dining area with venetian blinds (remaining electric shutters) Air-water heat pump
I also see points on very different levels. The energy standard is an overarching goal, from which requirements for walls, windows, etc. arise, and these may interact with each other. The wood of the staircase, on the other hand, is an implementation detail that influences other trades less.