Retention 5% Security Payment GU Construction Contract

Hello everyone,
I learned today from my neighbor that we (as the client) are allowed to withhold 5% of the contract sum as security.
The contract states:
The client is entitled to demand the provision of a so-called completion security. If the contractor does not provide this security for the timely completion of the work without major defects in the amount of 5% of the contract sum in accordance with § 650 m paragraph 2 of the Building Code, the client is entitled to withhold interim payments up to the amount of the owed security.

QUESTION:
- Who has done this? What was your experience?
- Did you inquire with the general contractor or directly deduct at the first payment? Our first payment was only with 2%
- Until when may it be withheld? According to the Building Code, until the end of the warranty period
- Must the payment possibly be transferred to a blocked account?

Thanks for your answers

Basically, you have a claim to a 5% retention, that is correct. However, the contractor can demand the payment upon submission of a warranty bond, i.e., a bank guarantees payment up to 5% in case of damage.

you did receive a warranty bond from LVM...

you did get a warranty bond from LVM...

That means that if you build with Heinz von Heiden, you cannot withhold the 5%?

Good question, in my opinion you would then have drawn twice, your retention and the warranty bond. Maybe others can say more about that.

Either or. The good thing about the guarantee is that after full disbursement you also become the owner in the land register. Currently, everything would only need to be registered as a preliminary note.