Construction work on the reactor had to wait until DuPont had completed the design. Excavation commenced on April 27, 1943. A large pocket of soft clay was soon discovered, necessitating additional foundations. Further delays occurred due to wartime difficulties in procuring building materials. There was an acute shortage of both common and skilled labor; the contractor had only three-quarters of the required workforce, and there was high turnover and absenteeism, mainly the result of poor accommodations and difficulties in commuting. The township of Oak Ridge was still under construction, and barracks were built to house workers. Special arrangements with individual workers increased their morale and reduced turnover. Finally, there was unusually heavy rainfall, with falling in July 1943, more than twice the average of .