Is it possible to sell the apartment and take over the home loan?

Hello, as the title already says, we bought a 4-room new build apartment of 114 sqm 2 years ago for 479,000 + extras like KNX smart home with all extras, bathroom + flooring for 20,000. It would definitely be sellable, as it also has an 11KW car charging spot and a 120 sqm large garden. We would rather not sell it, but we have now found a property nearby.
Data

[*]Planned semi-detached house from Hanse Haus. House price 459,000, finishing stage almost complete. (Floor coverings missing except bathroom, plaster + filling + doors)
[*]Basement with daylight 63 sqm, of which 45 sqm is freely occupiable, the rest is a technical room.
[*]5 rooms, living area 125 sqm without basement, you can still add a room of 30 sqm here.
[*]Plot 320 sqm for 145,000, both are purchased separately.

Now the data about us, 2 adults, 1 child 13 months.

[*]The apartment was financed with 380,000 + 120,000 equity, now there is still 80,000 equity available (total 200,000). The rate is 1,100€ with interest at 1.1%.
[*]I earn 4,250€ net + child benefit 180 + 1.3 salaries.
[*]My wife starts her teaching internship in February and earns about 1,000€ net in BW. I will then reduce to 35 hours and earn about 3,700€.

Can I transfer the old loan agreement + interest to the new property? What kind of incidental construction costs and buffer should one assume? I was thinking of 50k.

So financing is not my strong suit, but if you buy the land separately, then just buy it without the projected house. If that’s not possible, you have a developer contract, which means that the property transfer tax applies to the entire construct.
Expansion stage without interior plaster? That’s quite something.. 50k is never enough here. Besides the upgrades, the still outstanding work has to be done. I roughly estimate you’re already at 20k. Then you’ll want to upgrade even more. Plus the kitchen.
If I’m right about the developer, on top of the over 600k project costs, you’ll face very high incidental purchase costs. Overall, I estimate the requirement at around 700k. Of that, 80k equity plus 100k for the existing apartment. Then you’re at a requirement of 520k. That amounts to a monthly rate of ~2300€ in the current interest rate environment.
Whether the bank agrees to the property change can only be told to you by the bank.

As far as I know, one is tied to Hanse Haus because the owner is building the other semi-detached house with Hanse Haus and I think you get such a good offer. A lot is really added on top of that, maybe we will stay after all and wait for the Ref. After that, the joint net income would be around 6 - 7 k+, which then opens up other possibilities.

As far as I know, you are bound to Hanse Haus because the owner is building the other semi-detached house half with Hanse Haus and I think they get such a good offer.

Basically, you can build semi-detached and terraced houses with different companies. But the main thing is that you coordinate with each other already in the planning phase and ideally have a planner. I doubt that you will seriously save anything through the second half at Hanse Haus. If in doubt, the savings will be lost again because Hamburg’s standard does not correspond to your desired standard and you then start to add or remove things on a larger scale.

I just read your apartment thread again. ;)

What is making you consider possibly giving up the apartment now?
The garden won't get much bigger if you subtract the 320 sqm for the garage, house, etc. Is the location that much better or does it appeal because of an additional room?

I also think the price will be at least 700 K overall, probably more, since the additional purchase costs will likely relate to the land/house.

Back then, for you

Advantages:
Small property with only 8 residential units and no social housing
Good rural but still close-to-city location, connection to train and bus is great.
Nice layout of the apartment, garden, amenities, large masonry basement compartment with 14 sqm
Disadvantage:
Price
Possibly kindergarten

and it was the wish that your wife could start at the school next door. Did that work out? And how do you currently feel about living in the apartment?

The other party that owns the entire property will probably only sell it if you build with Hanse Haus.

So far we are still waiting for the reference allocation but very likely it will be another school which is also nearby. Basically we are satisfied with the apartment. The layout fits etc. The equipment is also great as is a large garden. We were only interested in the offer because a fitness room and a slightly larger basement would be nice to have. The location would be a bit better but that plays a minor role. However, I think with a total amount of 700k and the low added value it would hardly be worth it. Especially since interest rates and construction prices are currently at a record high.

Many thanks so far for the answers. Once the reference is done it looks different again and maybe you can buy something here then and still keep the apartment, because you won’t get one with a large garden again.