The Fucina espositiva (formerly Ercoli) is a building with load-bearing walls made of local stone, consisting of a central room of irregular trapezoidal shape and several smaller rooms to the north. The mezzanine structure consists of a wooden floor with primary and secondary framing.

The wing attached to the west facade has a reinforced concrete floor slab beneath which the Re sewer runs.

The roof of the main wing is gabled, with the ridge beam supported by a truss, while the projecting wing attached to the west facade has a gabled roof but with joists resting on the ridge beam and beams near the walls.

The roof is covered with clay roof tiles.

Open to the public during exhibitions and events, or by reservation at the Bienno Tourist Office.