The German standard DIN 18202, Toleranzen im Hochbau, sets how far walls, floors and ceilings may depart from the plan. It measures the gap under a straightedge at set distances. A homebuilders’ guide gives the table. For a finished wall, the gap may be 5 millimeters over one meter and 10 millimeters over four meters. Erst wenn die in der DIN 18202 festgelegten Toleranzen überschritten werden, liegt ein Mangel vor. Only when these tolerances are exceeded is there a defect. If the contract says nothing else, the DIN values are the minimum the builder must meet.