 Phase 2 consisted of replacing each of the numbered exterior wall stones in its original place, bolstered where needed by new stones to replace those damaged in the fire.Although the palace interior was originally made of wood, the reconstructed building was designed using reinforced concrete interior supporting beams for the walls, ceiling and roof due to concerns over the availability and durability of hardwood.Finally, the roof was re-tiled in blue-gray slate imported from quarries near the French city of Angers.