By Giuseppe Guanci

One of Prato’s most important factories, although very little known today, was Brunetto Calamai’s wool mill. The founder, born in Prato in 1863, represents the typical pioneer of the first stage of Prato’s industrialization: at the very young age of 15, he began dealing with the production of “mechanical wool” in the upper Val di Bisenzio area. It was an innovative processing method, recently introduced to Prato, which could be used only where hydropower was available.
In 1891, Calamai decided to build a new factory and purchased a water mill right above the one known as ‘delle Vedove’, placed along the same millrace, Gora Bresci, the so-called ‘Maceratoio’.

In the early 1900s, the factory was converted into a full-cycle wool mill, with all the processing stages being performed internally, from the raw material, either new or reworked wool, to the finished fabric. In 1922, the company became Società Anonima Lanificio Calamai. Three years later, when it became necessary to extend the plant to include a dyeing mill and a storehouse, the Calamais, who were entrepreneurs very attentive to the latest developments in the textile field, opted for a building in reinforced concrete and hired the young engineer Pier Luigi Nervi to design it. Nervi designed a structure with inclined beams in reinforced concrete and placed very apart from one another. The result was a building with a very lightweight roofing and an extradosed structure which caused a surprise effect on the viewer without, however, immediately revealing the architectural feat behind its construction.