KFW 55 material before building permit / start of construction purchase

Hello, We are currently still waiting for the building permit (according to the building authority in the final phase) for our planned two-family house in the outer area. KFW 55 is approved, we now want to buy building materials such as insulation, bricks, etc. Is this a problem for the KFW bank or does it not matter? Regards

I would, no matter what anyone answers here, as with grants, ALWAYS try to get it "approved" in writing by the KfW.

I believe the problem is rather that you will not receive any disbursement from the loan without a building permit. The bank wants to ensure that you actually build or are allowed to build their security.