Is the planned construction cost including the land realistic?

No, I don’t have any helpers from the construction site. I myself am an electrical engineer in industry, so I’m not from construction either. I’m just a hobby handyman and do a lot of DIY. The electrics shouldn’t be a problem, I also connected our photovoltaic system, wall box, etc. myself. Control cabinets for single-family houses come preconfigured and ready, I can also handle laying all the circuits...

I also want to install the other trades myself as far as possible. I’m confident enough to install a heat pump and underfloor heating, it’s not that complicated. I’ve never done it before, but there are plenty of instructions on it, in my assessment doable :)

Doing the electrics yourself is no problem. I’ve done it twice already. You’ll manage if you want to.

I would NOT do water and wastewater myself. No experience and it would just be stupid if it leaks afterwards. But it’s certainly not rocket science either.

You can install a monoblock heat pump and lay underfloor heating yourself. Just like the insulation under the underfloor heating plus edge strips.

You can also do plastering and paneling inside yourself.

You’ve already realized about the screed, have it done. I paid €6000 gross this year for 360 m².

But if you’re always alone at the construction site, you can forget it. Electrical work might just still be possible alone. Laying underfloor heating no longer. Paneling neither. You won’t get anything done alone. Especially since you’re totally lost without knowledgeable helpers. You either need an endless amount of time or you make construction errors or both.

My tip: Pick a maximum of 2 trades (e.g., electrics and heating) to do yourself. And try to organize the rest beforehand and find people for that. Trades that come at the very end, for example laying the floor, you can still do if there’s still strength and time left.

50 days of vacation isn’t as much as you think. Besides working, you always have to coordinate all sorts of things and a thousand things will come up that you don’t yet think of.

I’ve built twice now all with individual contracts and a lot of own work. You can save a lot of money that way, but you should have a budget in reserve in case it doesn’t go as planned or you have to have more work done.

Everything else within a year, the full annual leave (50 days in my case) is then used for the construction, the rest after work.

Hahaha sorry but 50 days are not even nearly enough. Also don’t fall into the misconception that you are anywhere near as fast as the pros because of your YouTube tutorials. For example, interior plastering: For me, two plasterers were busy for two weeks. Alone and untrained, you already need your entire vacation just for that.

A 160 sqm house will cost 160 x 3k = 480k, period. If you cannot clearly say yes to being able to afford that, then it has to be smaller. However, a normal family does not need this house size either. Is the plot of land already available? - that is actually crucial here, starting with the keyword Kellerregel. As a do-it-yourselfer, you will only be able to reduce the construction costs by the profit share of the trades you do yourself. Do not include price increases until it is time and also not insurance for helpers in this calculation.

A wooden house is not more precisely calculable than a stone house; both construction methods include shell houses. Proper so-called shell houses are best obtained from specialized providers who often offer one more expansion stage than the also ready-to-move-in providers, who usually already have three of those. So your idea of the standard "only interior paneling, as a complete kit" is not market reality. With a shell house, one should especially tend toward the catalog house, even though many providers advertise individual planning implementation.

Have a free architect design a house in "Module A" (see externally, now easier to find through my signature) "A house-building roadmap, also for you: the phase model of the HOAI!", then make a > resting phase > decision point in the > resting phase and decide on further proceedings according to the result (e.g. modification of a catalog model, see answers to question 2 of the inquiry at the decision point).

The employer’s claim to an employee recuperated after vacation is often forgotten. And a wet screed is not the first choice for a wooden house.

Start a thread linked in both directions here with the completed questionnaire from the head of the floor plan section, also present the plot and do not forget to mention the development plan (without link!).

Start a thread linked here in both directions with the completed questionnaire from the top of the floor plan section, also present the plot of land and don’t forget to mention the development plan (without a link!).

He is not that far yet.

I’m not that far yet. I’m currently trying to roughly determine whether we can afford the whole thing at all.

Better approach: go to the "Finances/Construction Costs" subforum and post your possibilities, i.e. household income etc.
Then we can see further where and how one can save through own contributions and where it is necessary.

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 work steps that can be undertaken independently due to one's own qualifications.

I consider the project, unless a large network is suddenly pulled out of the hat, hardly feasible. Too much is planned as own contribution here – you would have to take a sabbatical year and probably still not be finished.

Ability is one thing (already not a good sign if you have no experience). Managing to achieve the pure quantity in the given time is another.

And then come additional costs. Double burden of rent and loan. Cost of one's own working time. And so on.

He is not there yet.

Better approach: go to the subforum "Finanzen/Baukosten" and post your possibilities, i.e. household income etc.
Then one can see where and how savings through own work can and must be made.

I would sign off on that.

I would calculate the other way around: Price for the house without floor covering & painting work and then see which credits there are for which further work steps that can be undertaken by oneself due to own qualifications.

This is ALWAYS the wrong way for DIY. Why? The price for the shell construction (closed or however you want it) or the shell house is always lower than the house price minus credits. You can only lose money that way – and in case of doubt, a lot of money. Of course, you must have the resources and skills for it.