Mold on wood/ shell construction, is it possible to deduct the advance payment invoice?

I personally and my 3 neighbors have no problem with the plan as long as the final result is right. But thanks again for the tip with [Bauherren-Schutzbund]

Just imagine the developer goes bankrupt tomorrow. Then you will have already paid far too much for the service received. In that case, you would have a serious problem. But I’m keeping my fingers crossed that this doesn’t happen.

Thank you for your advice but it is about something other than my payment plan. The developer works by the way according to [markiere] and [Bauträgerverordnung].

Record it in writing as a defect and report it to your construction company (if you can't get an expert quickly to take care of it for you). Replacing the wood should not be a problem, just wait and see what the expert and the construction company say. Whether you can withhold part of the amount depends on your contracts. The shell is closed, it’s just about replacing wood worth 20€. A deduction probably isn’t proportionate. The payment plan is already reasonable for a developer project. The property is included in that.

Yes, as mentioned, the payment plan is not the problem. Replacing the wood will surely be difficult since the bitumen waterproofing membrane is glued on top. Would it be enough to sand down the rafters??

No idea :( you need to get an expert. Personally, I think it should be enough since it looks like [flugschimmel] and doesn’t seem to come "from above". But from a distance and without expertise, the statement is of course meaningless.