Evaluation of construction project with maximum own efforts

These two estimates are already diverging widely:

Then tell us here how they fit into your own estimates – with so many construction craftsmen in the family, you should actually know what customers usually get charged?

Then tell us here how it fits into your own estimates - with so many construction craftsmen in the family you should actually know what the customers usually get billed for, right?

My estimate, based on the experiences of family members and acquaintances, would be around €100,000, possibly a bit more.

Presumably, in comparison to "having it built," one must also reckon with additional costs from rent and provisioning costs. If I estimate a construction period of 2 years and assume it can be built by a general contractor in one year, that would be at least €5,000 cold rent and somewhere between €12,000 and €18,000 provisioning interest.

Just thrown into the room briefly, maybe it’s already outdated, who cares... The painter currently charges around 15,000 EUR for a 150m² single-family house without gluing fleece, just sanding and painting. I’m doing it myself now, a few friends are helping me... material costs so far, including drywall sander and workshop vacuum... 1,500 EUR. Just to put that into perspective of "material costs make up the biggest part"...

That’s far from true for all trades. The exterior top coat plaster was applied by 4 men, they took 2 days, so 8 man-days... and used several buckets of material... what was probably the biggest cost factor here? The few buckets of top coat plaster?

And... I might be wrong... my personal experience so far has always been: Free help when moving. Everyone starts out fully motivated and in the end, everyone is exhausted and causes more damage than they help you with. A bricklayer who works 50 hours/week in the summer... does he really do good work for you on the weekend when he’s laying bricks for you? And it has also come up... do they really all work for free? Weeks? Months?

By the way, you have no warranty claims against any of them... it was a favor.

PS: 100,000 EUR for 190m² just for materials? Good luck...

Just thrown out there briefly, maybe it's already outdated, who cares...
The painter currently charges around 15,000 EUR for a 150m² single-family house without glueing fleece, just sanding and painting.
I'm doing it myself now, a few friends are helping me... Material costs so far, including a drywall sander and shop vacuum... 1,500 EUR. So much for "material costs make up the biggest part"...

That’s definitely not true for all trades. The top coat on the outside was applied by 4 men, who took 2 days, so 8 man-days... and used several buckets of material... what was probably the biggest cost factor here? The few buckets of top coat?

And... I may be mistaken... my personal experience has always been:
Free help with moving. It starts out very motivated and in the end everyone is exhausted and causes more damage than they help you with. A mason who works 50 hours/week in the summer... does he really still do good work on the weekend when he’s laying bricks at your place?
And it has also come up... do they really all work for free? Weeks? Months?

By the way, you have no warranty claims against any of them... it was a favor after all.

PS:
100,000 EUR for 190m² just for material?
Good luck...

What I meant was 100,000 EUR saving potential through saving labor costs, not through material.

What I meant was 100,000€ savings potential through wage cost savings, not through material.

I compared that with my numbers and consider 100,000 euros quite realistic (including landscaping).

We did quite a bit ourselves (even if not as much as the thread starter plans). And wrote quite accurately how it usually goes.

We’re not professionals, we read a lot and watched a lot of "youtube", but after about 10 or 11 months on the construction site, us amateurs really lost strength. For us, it was rather the other way around – what many do themselves, we ended up outsourcing because we didn’t have the nerve anymore and just wanted to move in. Everything just takes a very long time when you can only work on weekends and after work. We wanted to lay tiles ourselves, but that went pretty mediocre and the result wasn’t so cool either, so we had the tiler do the entire ground floor after all, no nerve for drywall work on the sloping ceilings and had 3/4 done as well. We were afraid of messing up the wallpapering, so that was outsourced too. But we did the painting ourselves.
However, we erected the house ourselves with a master carpenter, put up the interior walls with him, and installed the windows. We insulated all the walls, added installation layers, insulated again, and then either covered or boarded them. We laid the solid wood floors ourselves... Quite a lot adds up, and in between I really regretted having started, because the feeling of being overwhelmed was really intense. By now I’m sitting in the about… 80% finished house and I’m really happy that we dared to do it.

But the work is really a lot, constant, and overwhelming.

In our case, almost all enthusiastic friends who WANTED TO HELP A LOT came around only about 2 or 3 times for a day during that year. I had naively expected more. And what has already been mentioned here – all the tradespeople in the family... Are they all retirees and have time? Or how should they build your entire house alongside their own working hours? We anyway only have "useless" (as far as the construction is concerned) academic friends, so the expectations for the quality of help were at least low ;).