Preliminary contract for house purchase or right of withdrawal from house purchase?

How come? You yourselves live in the house until the new building is finished?

Since we are moving to a completely different region, we will live in a rental apartment for a few months in the meantime until the new house is completed.

The purchase contract can of course be concluded months in advance, but you will only have the buyer's money in the account upon transfer of use.

No, it doesn't have to be that way. Example of a colleague: sold, received money, can continue living there for free until day X, if it takes longer, he pays rent.

Since we are moving to a completely different region, we will live for a few months in a rental apartment in the meantime until the new house is completed.

That is of course something different. But all the more reason not to rush anything regarding the contract.

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Where did you get the information that it will become more expensive??? I hope not from the salesperson himself

In the meantime, I inquired at the parent company when the prices will be increased next year. Indeed, on 01.01.2020. At first, they did not want to give me any information there, only after I pointed out that for the independent sales representative, it does make a monetary difference whether we sign a contract on 28.12.19 or on 04.01.20. That was rude of me, I know.

No, it doesn't have to be like that. Example of a colleague: sold, got the money, can continue living there for free until day X, if it takes longer, he pays rent

It is also a variant we are considering, since for us it is only about living there 1-2 months longer.

Seems to me like you're voluntarily begging for your price increase.