How do you take the interest into account from the purchase of the land until moving in?

I have a similar question:

We plan to start construction from May 2019. We could finalize the financing as early as December or only shortly before the start of construction. The interest-free period on the loan commitment is 12 months, and the construction time is also about 12 months.

If we finalize the financing this year, we will pay interest on the unused amount after the 12 months have elapsed. If we wait with the financing until April/May – the terms could correspondingly be worse.

What are your experiences here, which option is better?

No one can look into a crystal ball to predict what the conditions will be in April/May 2019.
Also, we do not know what your payment schedule looks like. How much is the amount that you have not drawn after 12 months?
How high is the interest for undrawn money?

In any case, one could try to negotiate an 18-month interest-free period on the loan commitment with the bank.

Experience won't help you there, it depends on how the interest rates develop. It's gambling. If you decide to "wait," don't wait too long; by the time everything is signed and sent back and forth, the mortgage is registered, and the cancellation period has expired (in other words, all payment conditions are met), more time passes than I would have expected. (For us, probably over a month, but with us, the mail was incredibly slow at one point. A one-week mail transit time is certainly not normal)

Why? What speaks against having the interest financed?

You can also make everything look good on paper. The financing bank would then have to pay this out as a residual item without proof. Some credit unions are said to have a problem with this because it usually involves 100% financing and nothing value-enhancing with the property at all.

"Good" financing with solvent borrowers should not have this problem at all

Besides, we don’t know what your payment plan looks like. What is the amount that you have not drawn down after the 12 months?
What are the interest rates for undrawn money?

In any case, one could try to negotiate an 18-month interest-free availability period with the bank.

We do have an overview of what percentage is to be paid according to construction progress, but no timeline. That means we cannot quantify the undrawn amount after 12 months so far.
I will inquire about the current conditions in December and decide afterwards. If the conditions are somewhat better due to the end of the year, I will probably secure the conditions already this year.

If you decide to "wait," don’t wait too long; it takes more time than I expected until everything is signed and sent back and forth, the land charge registered, and the revocation period expired (i.e., all disbursement requirements fulfilled).

Good hint, I wouldn't have expected something like that.

Just because of the given occasion :-p

Through the thread, I just spoke with my financing broker earlier to ask which loans should be drawn in which order and how high the commitment interest on a balance of €220k from 01/30 will be.

Result:
From 01/30, we pay the full installment (interest + repayment) of €1600 + about €560 (presumably) commitment interest.

On top of that, the ongoing costs. :-p

Mind you, we are only starting to build massively with the basement as of Monday. Of course, I was aware of that, but we had expected a start of construction as already mentioned in spring 2018.

All of this is still doable, but the monthly savings rate is now only somewhere around €800-1000.

That means something like this should also be planned and taken into account.

One good thing about it: from 01/30/19 we start repaying the loan and possibly only move in in August 2019.

Result:
From 30.01. we pay the full installment (interest + repayment) of €1600 + approx. €560 (presumably) commitment interest.

Which bank does such nonsense? It's totally abnormal, since the normal installment cannot be charged at all – interest only on the amount already disbursed.

Normally, there is a formulation in the contract: The first installment is due on..., at the latest after full disbursement.

Better ask your bank and not the broker.