
Although trial holes were bored to test the resistance of the soil it was only when work began on the foundations that it became apparent that the land on the Seine side of the building would not support the weight of the building. There was no choice but to build on piles: 3,400 oak piles were used, but the whole project was delayed by eight months, and costs overran significantly.
When the foundations were completed, the masons could go to work. The task was gigantic: the facade overlooking today's avenue Winston-Churchill alone required 17,000 m3 of stone, 10,000 m3 of rubble and 2 million bricks. To win the race against time, the most modern techniques were used: rail and gantry cranes, steam engines, and sheer muscle. Plenty of it: at the peak of the construction work, there were 1,500 workers. Strikes for higher wages broke out, putting further pressure on the bid to meet the deadline.
