Impacts on loan when equity is in property

Everything has already been explained correctly here.

Just a small note:
If you buy a property at a price of, for example, €100,000, this does not necessarily mean in reverse that the bank also values the property as €100,000 equity.
http://de.wikipedia.org/wiki/Bodenrichtwert

Thank you very much for the many good advice. Then we still have to do a bit of calculating and negotiate on the [Grundstück].

The bank does not look at the standard land value as an isolated figure; for the bank, the market value is the only decisive factor.
Let's assume you buy a plot of land today for 50 euros x 600 sqm (30,000 euros). In 2 years, the land value has risen to 150 euros (dreaming is allowed :D), if you were to plan financing only at that time, you would suddenly have (90,000 euros).

The standard land value is only an aid to calculate the market value. "Enthusiast" prices are not taken into account.

we also bought the property in advance, the value was then counted as equity, although we also had a few euros of additional equity set aside.

which, by the way, has since proven to be a jackpot for us: our bank also offered us legal protection for the construction as part of the financing.
I’m afraid that by the time we are finished with everything, the insurance company will have taken the exclusive offer of equipping builders with something like this off the market again...

If laws are referenced, please refer to the relevant ones. The market value is "irrelevant", the lending value is decisive and there is also a basis for that.

@ all Both:

The market value is not the sole basis for a bank. But strictly speaking, the lending value is also not the sole basis (for what exactly?). Various values go into determining the lending value. There are different determination methods. The method commonly used for owner-builders usually determines an asset value, which results from adding the construction value and the land value. But the market value of a property also factors into the consideration for determining the lending value.

For example, a beautiful house on a large plot (family-friendly, pleasant to look at) is not worth much if nobody wants to buy it at the asset value. Unfortunately, it may have been discovered afterward that industrial waste was deposited nearby and on the other side there was (to great surprise) an Indian burial ground.

The value of a good is ALWAYS determined by what others are willing to pay for it. Of course, exceptions are to be disregarded (... every morning a fool is born ...). Asset value okay, market value good = high lending value. Asset value okay, market value poor = low lending value.

Basically, both of you are (partly) right.

However, I agree with Tox again afterward. In detailed business with construction financing, special consideration cannot usually be given to individual cases. The costs of extensive negotiations would also have to be borne by someone again. ;-) But trial also makes you "smart" here.