The Triennale design Museum offices occupy a renovated portion of the yard behind the Impluvium of Palazzo dell'Arte. On the occasion of a Triennale in the 1950s, a reinforced concrete staircase was built and it still partly exists. Today is on the ground level located bookshop storage spaces. The surfaces of the yard opposite it were clad with the traditional classic bare brick that distinguishes the whole of Muzio's building.