The private individual is liable for damages caused by the company YOU selected due to possible construction defects?
Of course, the neighbor as the injurer is also liable for his contractor even if he was not free in choosing him - even if he had to tolerate that the right to propose the contractor lay with the injured party. If the injured party had agreed on the damage with the neighbor’s contractor, that would be an independent criminal act, also punishable, but the burden of proof would not lie with the injured party. But try telling your doubts to a law professor, that should at least be an interesting topic for a term paper.