Construction began in the summer of 1861, though setbacks would delay it for another fourteen years. During the first week of excavation, an underground stream was discovered, rendering the ground too unstable for a foundation. It required eight months for the water to be pumped out, though enough was left in the area which eventually became the fifth cellar for operating the hydraulic stage machinery above. Garnier's double-walled and bitumen-sealed cement and concrete foundation proved strong enough to withstand any possible leakages, and construction continued.