Build? Buy? Prefabricated house? Solid construction? BW/RLP - DH/Semi-detached house

Sought/Wanted:
- Semi-detached house (dream)
- Semi-detached house with granny flat
- Single-family house with granny flat
- Two-family house

Budget including land calculated:
400,000 (if okay)
500,000 (if the house is perfect & relatively new)
600,000 (if it’s a semi-detached house)

So, in short: buy a house where you also have rental income so that costs are not too high.

Background:
We have been searching for quite some time. But we just can’t find anything that really fits, especially because prices are so extremely high. It’s also not that easy. My girlfriend is from Worms and I’m from Stuttgart. We want to have a home somewhere between Mannheim & Karlsruhe/Pforzheim or between Mannheim & Heilbronn. Along the highway basically. So near Mannheim, Speyer, Karlsruhe, Bruchsal, Sinsheim, Heilbronn. Smaller “cities,” but it doesn’t have to be in the city. Can also be 10 minutes away or so. So far, we have found fairly well-located houses in the Speyer Phillipsburg Germersheim area. That’s on the border of BW to RLP. Whether those are inexpensive, I can’t say. I usually compare the price per sqm on homeday.

A dream would be to build a semi-detached house with 2 semi-detached units each about 110-130 sqm. One to live in ourselves, the other rented out and sold eventually.
First, we looked at prefabricated houses (wood). For example, we had an offer of 550,000 all inclusive (including land) for the complete semi-detached house. After consulting with a few people, it turned out that wooden prefabricated houses creak because the wood “lives.” We have no desire for that at all. So that’s out. Also, the offer included 170,000 for interior finishing, where colleagues said it wouldn’t cost 100,000€, but okay.

I contacted many solid construction companies but many didn’t answer at all. Two of them quoted 300,000 per semi-detached unit if you want a semi-detached house. + land so about 750,000-800,000. That’s way beyond our budget. No idea if there are still solid construction companies here that could manage our 600,000 including land (about 150,000 of that) budget. We also considered just having the shell built for XXX.XXX € and managing the interior finishing ourselves. But no company offers just the shell; mostly either almost finished or turnkey. We know many people who could do windows/doors, floors, sanitary, electrical, plastering. But unfortunately, no one does the shell. Do you think that would be feasible?

•••••••••••••••••••••••
Otherwise, we went back to searching for houses:
We find semi-detached houses quite nice. Especially with the possibility of a granny flat.
We have now found one or two near Speyer:
••• One semi-detached house (Offenbach / Pfalz) was built in 1994 and costs 500,000 (agent). It’s huge, 250 sqm (9 rooms) and 450 sqm land with a double garage & photovoltaics for water & sauna. The granny flat is in the basement approx. 60 sqm (2-3 rooms including shower & toilet) but no kitchen yet. Access via garden or through the house possible. Upstairs are 4 rooms + attic finished but not counted. One room approx. 15 sqm.
On the ground floor, there's an office + large living-dining area with kitchen, all Miele, approx. 20,000€ value. Covered terrace and large garden.
However, some moisture has appeared on the wall in the granny flat basement. Allegedly because it was closed up too early. Also, there are moisture problems in the Hebel room because no ventilation was installed. According to the agent. The equipment is almost upscale but somewhat older of course since it was built in 1994. Knee wall 1.60 or 1.80 m.

••• Another semi-detached house was built in 2018 in Lingenfeld. Costs 520,000 private sale. Has about 160 sqm living space plus terrace 17 sqm approx. = 177 sqm. 250 sqm land, small garden.
Open living-dining area including small nice kitchen. Shower and guest toilet on ground floor. Upstairs are 3 rooms and bathroom/shower. Below is a 2-room granny flat in the basement approx. 48 sqm including kitchen and shower/WC. Separate entrance right at the house entrance, stairs down separated stairwell. Hip roof. Knee wall 2 m. With a garage with electric charging possibility. All very new. Much smaller, but everything is NEW. Equipment also upscale. I haven’t talked about the price yet. But I think you can negotiate down to 500,000 here. Or even less in a private sale?

So now my question. Is it better to buy the new one? Better to buy the older one because it is much bigger but the location is not optimal and possibly needs a lot of work?
OR ... would it be sensible to build ourselves for this price? Possibly a semi-detached house that looks exactly like the new house mentioned above? Provided it can be done for the price. At least the land would cost 50,000-100,000 for the semi-detached unit. And then you’d have about 300,000-350,000 left for the house construction.
OR commission the shell and build a semi-detached house and manage the interior finishing yourself?

So many questions. There are 1000 options but which makes the most sense??

I hope I’m not overwhelming you.

So, briefly put: buy a house where you also have rental income, so you don’t have such high costs.

For that, you have a tenant who can cost nerves and money and you also have to provide more capital.

First, we looked at prefabricated houses (wood). For example, we had an offer of 550,000 all-inclusive (also land) for the entire semi-detached house.

Either in the middle of nowhere or with minimal features and perhaps missing incidental costs.

After consulting a few people, it turned out that prefabricated wooden houses creak because the wood "lives".

What nonsense, rarely laughed so much...

Furthermore, the offer included 170,000 for interior finishing, where colleagues said it wouldn’t cost 100,000€, but okay.

Then let your colleagues build it.

I contacted many solid construction companies, but many didn’t even respond. Two of them replied with 300,000 per semi-detached house if you want a semi-detached house. Plus land, so about 750,000-800,000. That blows our budget out of the water. No idea if there are still solid construction companies here that could manage our 600,000 including land (about 150,000 of that). We also thought about just having the shell built for XXX.XXX € and then managing the interior finishing ourselves. But no company offers just the shell, usually almost finished or turnkey. We know so many people who could do, e.g., windows/doors, floors, plumbing, electrical, plastering. But unfortunately no one who does just the shell. Do you think that would be feasible?

First: prefabricated house (wood house) and solid construction house cost about the same. Prefab tends to be more expensive. Second: If you take a general contractor / house provider, they want to sell you a piece of the house. If you want to distribute everything into individual trades, then build with an architect. Do you actually have construction knowledge to manage a quite complex and technical house build yourself? Besides the enormous time required. The "people" you know also don’t work for free, by the way. And the materials cost money one way or another. Regarding the two houses. Moisture is, according to every realtor, unproblematic — at least until you’ve bought and can no longer get rid of the mold. Price negotiation today goes (except for the middle of nowhere) the other way round. Whoever offers the most gets the house. It sounds like you still don’t know how you actually want to live. Plus the fixation on the granny flat. Think carefully in advance about what you really want. For house construction, you can roughly calculate 2,000€ per sqm of living space. Plus additional building costs and special wishes or basement as well as the land and kitchen/furnishings. A semi-detached house is the same price as a detached house but requires less land area. With existing buildings always remember that you usually say "can move in as is" but then still have many wishes. Alternatively, older properties always need renovation.

Renting must be affordable - preferably not where you yourself live. Convincing oneself that living under the same roof with a tenant is a dream might be considered an April Fool's joke. Otherwise, I read plenty of barroom slogans - hypotheses that others tell, which should first be examined closely to see what they are really about.

Renting out in batch size "1 residential unit" is the ultimately most pointless zero-sum game (except possibly if the rented unit is noticeably larger than the one used by oneself, and/or in a higher-priced location). A good age for a second-hand house is between ten (repaint, technically everything can stay, defects are fixed or did not exist) and twenty (technical maintenance will soon be necessary) years. Younger rarely pays off, older the price decline is compensated by renovation effort. Divorce houses are the best, otherwise at this age dumb neighbors could be the reason for selling. Thanks for the joke about the creaking prefab house, I hadn't heard that one before.

It is a pink cloud to believe that a tenant finances someone’s house to a large extent

You are already listing how much a house without and with a granny flat is allowed to cost. Then you can also calculate how many years of rental income you need to break even, let alone make a profit.