Is the planned construction cost including the land realistic?

Yes, but he is not suitable for DIY at all. Anyone who believes they can get a shell construction ready to move in within 50 days of annual leave on their own can no longer be wished a speedy recovery, but only hoped for a mild course without permanent damage. 50 days, that would be my estimate for doing painting, laying floors, installing doors, assembling kitchen and furniture, and moving in alone.

What he is planning will easily take 2 years if done alone alongside work.

I would calculate the other way around: Price for the house without flooring & painting work and then see which credits there are for which further steps that can be done yourself due to your own qualifications.

That is ALWAYS the wrong way for DIY. Why? The price for the shell (closed or however you want it) or the shell house is always lower than the house price minus credits. You can only lose out on that – and in doubt a lot of money.

No, I have no doubts about that – and furthermore have mentioned several times that "shell plus" is definitely cheaper than "ready to move in minus" (because at least the profit margin of the "removed" trades remains).

Of course, you have to have the resources and the skills for that.

The "alone" is still not enough. Weekend DIYers regularly massively underestimate the phenomenon of the declining (oh, what am I saying: steeply falling) productivity curve late in the day. And that the "following" tradesman no longer has time and must be replaced by a more expensive one if the DIYer finishes his interface delayed.

Anyone who believes they can get a shell ready to move in on their own in 50 days of annual leave really can’t even be wished a speedy recovery anymore.

I can easily fill 50 days alone with breathing, snacking, and wringing out a headband; no work is done yet – so the work still comes on top. After two weeks of rehab for muscle soreness, of course (and I haven’t even injured myself yet). You can take a look here once at what real speed is with . That might go a quarter faster in new builds than in existing buildings, where you already have to work around plan-deviating realities.

Yes, but it is not suitable for DIY at all. Anyone who thinks they can make a shell construction ready to move in within 50 days of annual leave on their own,

I know exactly how it is. With the disadvantage that I first had to get the shell construction state on the old building.
It won't work in 50 days.

(...) I can easily fill 50 days just with breathing, snacking, and wringing out the headband, and nothing is accomplished yet - so the work still comes on top. After two weeks of rehab for muscle soreness, naturally (and I haven't even injured myself yet). (...)

Unfortunately, that's how it is. After 2 weeks of full throttle on vacation, I just paused for 3 days because my back gave up. Today it was better again, but much slower than before...

We have the following personal contributions:

- Laying and gluing parquet without interruption between rooms
- Installing doors ourselves, including one sliding door
- Complete plastering and sanding
- Interior painting work, and a little bit on the exterior plaster
- Network cables including empty conduits
- A few electrical cables that the general contractor could not offer us
- Installing bathroom fixtures
- Installing doorbell
- Very large photovoltaic system

Mainly, only my wife and I will do this. We both have 40-hour jobs and have saved our vacation. Although we are building only 103 sqm, I still fear that we might outsource a little bit because it might be too much.
Paving, garage, carport, garden, smart home, etc. are also all personal contributions, but we are postponing those for now.

For a bigger house and even more personal contributions, you really need a lot of help and endurance, I think. I am already annoyed by the construction preparation because I have to arrange things daily by phone and email. Also, a lot gets botched by all kinds of parties. If you can afford less personal contribution, I wouldn’t overdo it.

[Pflastern, garage, carport, garden, smarthome, etc. are also all done by ourselves, but we’ll put that aside for now.]

That’s when it really gets interesting. Interior finishing of the house, that’s still doable. In the garden, everything is many times harder, both regarding the excavation, the necessary frost protection subbase, and the material itself.

After a long back and forth, I have now decided to hire a landscape gardener for certain tasks. Moving 20, 30 cubic meters of soil, hauling away 15 cubic meters of clay, setting 120kg heavy block steps. That’s not possible without heavy machinery and especially not without being able to operate that machinery precisely.

I wanted to do everything myself, but in the garden with dozens of cubic meters of gravel, concrete, stones, soil, gravel. You reach your physical and above all your time limits. But financially, it really hits hard. For such a "digger day", I work for a whole week.