Well, you should definitely think it over and be upfront with the bank. The users here don’t mention these additional unexpected costs because they like to paint a bleak picture, but because they have all, in one way or another, experienced that something else came up during the construction process that was neither planned nor budgeted for. And if this is already exceeding the budget, then you should also consider stopping the entire project, because at this point it might still be possible to end it without a major financial blow. And don’t react indignantly right away, but think carefully, look at the problem from all sides with really good friends/relatives, and above all don’t sugarcoat things, but stay realistic.