Provision interest free for 12 months?

Construction period interest is called:

- Commitment interest on loan portions not yet drawn
- Contractual loan interest on the drawn loan portions

The loan is already "working" and the bank wants to make money :-)

The bank has charged you interest here for 3 interest days on the drawn amount of 5,000,-€ at 1.66%. Provision interest is only charged by the bank after the expiration of the date agreed in the loan contract, that is, from February 2016 on the amount NOT YET DRAWN. The bank must keep the amount available for you at the agreed conditions and, simply put, cannot use it. The provision interest usually amounts to about 3.00% p.a.

It can financially break one's neck if the commitment interest is set too low, so we have a construction period of 6 months with own contribution, then maybe 8 months, and the commitment interest does not apply only after 12 months but from 9. Could that cause a serious problem or is it easy going?

Just calculate it... interest rate - so 0.25% or 0.15% (depending on the bank) * unused amount... even if it is still 100,000 euros, it will cost you 150-250 € per month. If that is not available, just plan the whole amount as a buffer already with the amount taken out. The interest during these last months will be above 250 € by the way... so a certain double burden always occurs. The Commerzbank offers 2 months standardly - that already makes a difference. Depending on the amount taken out (e.g. 300,000 €) and term (e.g. 15 years) a 0.1% interest difference is about 2250 € (with full repayment) or 4500 € (with bullet repayment). Provision interest for 2 months would (with the start of drawdown after 2 months - not so unrealistic, since at the beginning you are rather still hesitating, pouring the foundation slab etc. and 10 months total construction time with even drawdown, again 300,000 €) cost you 3000 € at 0.25% - so it would be cheaper, for example, to choose a loan that is 0.1% more expensive with a long provision period. Additional costs for the possibly missing liquidity I have not even calculated yet.