The Royal Ice Factory’s silos

After being collected from the tanks and transported to the ice production and conservation building, the ice plaques were stored in silos, where they remained throughout the winter. With the arrival of summer, when the ice was to be shipped to Lisbon, the blocks were compacted and cut, and then wrapped in straw, hay and burlap to withstand the journey.
The building of the silos or wells preserves some monumentality. There are three silos, the largest being at the centre; as to the other two, one is facing west and the other is facing east. All are covered by vaults, being accessed through doors located under the base of these vaults.
The central silo has a circular plan, nine meters deep and seven meters in diameter. In its background, the parallelepipeds supporting the wooden platform where the ice was arranged are still visible. Something interesting was found on its walls: a set of vertical lines is crossed by a horizontal line, which was designated as «accounting writing» – it was a way of controlling the quantities of ice leaving the factory.
The other two silos, smaller and less deep, have a rectangular plan. The dense walls of these structures, associated with the location of the building, protected by vegetation and without exposure to sunlight, created the perfect temperature and humidity conditions for the conservation of the ice, until it was shipped to Lisbon.
The cover of the central silo is located in the north of the building, and the “fan-shaped” limestone slabs and the buttresses supporting this impressive structure are visible on the outside.
In the late 1990s, the recovery works in the Royal Factory’s ice production and conservation building maintained all the structures that were visible at the time.  Railings for the silos were built for safety reasons, thus ensuring conditions for the conversion of the space into a museum.