New construction with KFN 297, building savings and interim financing

Do I have a thinking error here or should this work relatively well?

The thinking error is that the bank probably won't finance this if the burden is >50% of net income without additional costs. A 3% salary increase is nice, but who says the company will still exist in 2 years and who says we won't have a longer period with significantly higher inflation? Then it will be tighter rather than better. And a few overnight stays from hikers are nice and all, but certainly not particularly economical. With two such small residential units, the resale value is also questionable, which could ruin the already poor loan-to-value ratio for you at the bank (because there is no equity contribution). Combined with the high burden, I would be surprised if this gets financed.

Are the 90 m² usable area in the basement? Then 300k€ is not enough.

No, it is a bungalow. The choice between slab foundation and strip footing + slab foundation will then be made depending on the foundation situation.

For 2 separate apartments, that is also not enough, unless water/heating/internet/TV etc. is not separate.

According to my interpretation of the question:

There are 2 residential units according to the KFW leaflet, i.e.
- Each unit has a living space with kitchen/dining/sleeping (my preference for over 10 years)
- Each unit has its own bathroom.
- Each unit is separate and lockable (apartment door)
- Both apartments share the entrance with access to the technical room. (According to the KFW hotline, however, not necessary)
- Separate meters are planned for water and heating, but important note, thank you.
- For internet and TV, I do not yet have any specific planning.

Are the 2900.-- net already including health/social insurance and retirement provision?

Yes, since I am subject to social security contributions, all contributions are already considered. Private provision is planned as soon as the loan is repaid.

With a new building savings contract, you just don’t get credit interest to get a cheaper loan in a few years. That contradicts your attitude of putting everything in ETFs and leaving it there, because you are sure to get 5% after taxes there.

That is a valid point. I should take that into account.

The error in thinking is that the bank will probably not finance this with a burden >50% of net without additional costs. 3% salary increase is nice, but who says the company will still exist in 2 years and who says we won’t have a longer period with significantly higher inflation? Then it will be more tight than better. And a few overnight stays by hikers are nice and fine, but certainly not particularly economical. With two such small residential units, the resale value is also questionable, which could finally ruin the already bad loan-to-value ratio at the bank (because no equity contribution). In combination with the high burden, I would be surprised if this is financed like this.

I think, if necessary, I could offer part of my equity (ETF) as collateral or, depending on the loan conditions, up to 50% of the loan could be paid back immediately with it, which would at least halve the monthly payment.

On the subject of the floor plan, I am creating a thread in the floor plan subforum. Here, however, I am still waiting for feedback from the home building company. In the thread/forum, I wanted to focus specifically on financing.

I think, if necessary, I could offer part of my equity (ETF) as collateral or, depending on the loan terms and if needed, 50% of the loan could be repaid immediately with it, which would at least halve the monthly installment.

Pledging stocks as collateral is difficult. Few banks do that. Better to use equity straight away and reduce the loan. Your income is not high enough to engage in interest rate arbitrage here.

Pledging shares as collateral is difficult. Few banks do that. Better to use equity right away and reduce the loan. Your income is not high enough to engage in interest rate arbitrage here.

That would be my emergency option (more equity, e.g. 100K). But it’s interesting that you can’t use something as "stable" as an MSCI World as collateral. I could understand it with individual stocks.

Alright, then I’ll wait for the specific offer from the home construction company, if possible including ancillary construction costs (everything from one source), and then take it to various financial advisors.

At least I should be able to afford it, I think. I have been working for 7 years and was able to save 50% of the equity (150K) during that time. So 300K doesn't sound unrealistically high. Fortunately, I can't pledge my company shares, otherwise banks might get some ideas (-;