The construction of the Tenaille von Fersen date from different eras. In the construction work started in 1773, a horse-drawn grinding mill was built at the eastern end and a bakery, with six large baking ovens and a vaulted biscuit drier on top of the ovens, in the middle part of the building. A granary stood on the site now occupied by the grand banquet hall. At the beginning of the Russian period, the building was used for its original purpose. In 1843, however, there is a mention of the grinding mill being broken and out of use. The topmost floor of the building was so badly damaged in bombardments during the Crimean War that it had to be torn down and was left as a low attic floor under the tin roof. After 1915, a central electricity station, still in use during the Finnish period, was built in the old grinding mill room.
In the renovation, completed in 2006, the Myllysali hall was converted for use as a banquet and concert facility for approximately 60 people together with the foyer of the banquet hall. Originally the building had two floors. A triangle-shaped loft, leading to the toilet facilities, has been built as a reminder of the old wooden intermediate floor.
The floor of the Myllysali hall, consisting of parts made during different eras and from different materials, was kept and restored. The ceramic tiling (built in 1915) was repaired, the old floor ducts were covered with new steel plate covers and dents in the concrete were filled with pigmented concrete.