Single-family house, granny flat, double garage + basement - construction cost 1,000,000?

What would actually be worked on in the basement? Wouldn't that be possible in a more spacious garage or a shed/garden house? If so, that would save a lot of money at once with hardly any disadvantages.

Let's put it this way: How much are you willing to spend?

We build somewhat smaller than you, 90 m2 heated basement and a correspondingly sized house above it. Regarding the offers you have, I consider the million more realistic than the 800k for your wishes.

What is actually being worked on in the basement? Wouldn't that be possible in a more spacious garage or a shed/garden house? If so, that would save a lot of money at once with hardly any disadvantages.

It is certainly often sensible to advise future builders against unnecessary expenses for space they do not need. However, we plan to significantly restrict ourselves in terms of space in the future – if I wrote that we need 50 sqm of additional storage space, I meant: need. Since these are expensive pieces of equipment and tools, we cannot just store them in a shed. Unfortunately, enlarging the garage is not an option, as we have already largely used up the buildable area. We have also pondered this in the past. The same applies to the granny flat – here too, tips on reduced space planning are certainly absolutely correct in other cases.

Granny flat. Check if you can really manage a flat for care needs with 50 sqm. I recommend the site Nullbarriere. Care requires space. Does the relative really need a complete flat, and wouldn’t a private bathroom with bedroom attached to your flat be more sensible? Why a kitchen if you prepare 90% of the meals anyway? Why a separate living room if your living room is used mostly?

However, our relative leads an independent life, currently also lives on significantly more space, and should in the future not alternately use our kitchen or living room with us. :)

Let’s ask it the other way: How much is it allowed to cost? We are building somewhat smaller than you, 90 m2 heated basement and a correspondingly sized house above. Regarding the offers available to you, I consider a million rather than 800k more realistic given your wishes.

Including incidental building costs, we actually wanted not to exceed 850,000, but could possibly finance a bit more if necessary. That should also include an amount for some outside landscaping. What is the range of your pure construction costs, without incidental costs?

If he lives independently, then that doesn't make sense. It was only a suggestion. Then see if he can manage with 50 sqm. If the relative is physically impaired, a different space requirement applies. Turning radius, aids, or caregiver.

Something has to go. If not the basement, then something else.

What is the range of your pure construction costs, excluding additional costs?

We are at €2400 / usable house area (living + usable area). Without the frills, we would have landed at around €2100.

That a partial basement is a (Hornberger or) step backwards is pretty much the only thing I can seriously answer to your questions as long as the project is not known to me in image/plan. And that brick facades regularly turn out to be more expensive than clients naively imagine.