Financing semi-detached house and all additional costs

This would then be a tied transaction. Yes, the additional costs also come on top of that. I also mention that I am 25 years old, my girlfriend is 22 years old; the basic idea of educating ourselves about building only really came about when a couple we know from before built and paid just under 300k for the entire construction, and they now pay 800€ monthly. In our area, a *modern* 3-room apartment costs 750 euros cold rent, so that’s how the idea came about to get informed about building, but if I have to read that a monthly payment of 1500 euros is required, it probably won’t work out, although I believe the term is less than 20 years?

The question is: what else must additionally be paid by the client? Do you have the ID of the offer?

Since my grandpa built with the construction company, I have of course already spoken to him. The duplex would be from Heinz von Heiden. My grandpa said that the prices are complete and that only the extra costs for special features are added. The price is not listed on the Heinz von Heiden website, but I got it from another website.

I believe that the cost breakdown for BW is too low and the income is too little. I do not see this as a situation for becoming happy.

If I interpret the information regarding the land price correctly, then he only pays the incidental purchase costs on the land. Plus notary, it amounts to 7.5% of the land price. That's just under 3000€

That's what I'm saying, although I can't get enough information from the first post to determine the land price.

I don't see any 120% financing here, unless it is a tied transaction. Rather a 97% financing.

Yes, you're right ... You can and will calculate it that way. Plus your own contribution ... The savvy financial advisor will manage that . Hence my advice: Go to the bank! But I didn't want to create any euphoria ...

Again for the questioner, loan 300,000 euros:

[*]Interest 2%, repayment 2% --> 1000 euro monthly rate, 35 years term
[*]Interest 3%, repayment 3% --> 1500 euro monthly rate, 23 years term

You can still do some calculations yourself ... and ask your bank.

Another question is how reliable the cost estimate is (so will it remain at 300,000 euros)?

Since my grandpa built with the construction company, I have of course already spoken to him. The semi-detached house would be from Heinz von Heiden..my grandpa said that the prices are complete and that only the extra costs for special features are added. The price is not from the Heinz von Heiden website but I got it from another website

Heinz von Heiden is currently saving on many things. These are not only features but also containers, portable toilets etc.
Painting and floor coverings are additionally charged externally. Painting refers not only to the interior but completely to the exterior as well.
Outdoor facilities are also external.
I don't know if Heinz von Heiden acts as a developer, but ancillary building costs are probably not included in this price. Because Heinz von Heiden is not that cheap (153,000 including ancillary costs) either.
I would add a little more buffer there and have the detailed description of services and the contract checked very carefully for hidden costs.