The large Baroque staircase with two flights, adhering to the east side of the building, in fact bears the date 1696 engraved on the central pillar of the balustrade, adorned with 18 coats of arms.

Some notarial deeds drawn up between 1491 and 1496 testify that in those years Andrea Beccaria and his brothers paid some Milanese stonecutters, Alessandro Bossi and Domenico Solari, then engaged in the reconstruction of the family's domus magna, and therefore probable that the current palace it replaced a previous stately home of the family (of which the tower remains, leaning against the western part of the facade, now trimmed and reduced to the same height as the building).

The surface, extended to two floors above ground plus one under the eaves, remained entirely in exposed brick, is divided into two parts by the large string course in terracotta, decorated with plant motifs with interspersed coats of arms and profiles of characters marked by a typically Renaissance taste.

[5] Each of the backgrounds thus obtained (which perhaps originally should have been plastered) was intended to house a window, surrounded by a frame, surmounted by a decoration with fauns and bucrania, also in terracotta.

The interiors were extensively remodeled between the seventeenth and eighteenth centuries and retain Baroque stuccos and frescoes, while in the middle of the great staircase, the fifteenth-century funerary slabs of members of the Bottigella family from the church San Tommaso are preserved.