After its establishment as a prison in 1817, the Sennhof underwent numerous renovations and changes over the next two hundred years. Initially, the ill-suited prison building allowed little sunlight and fresh air into the low, sometimes damp cells. Dangerous inmates were placed in solitary confinement. Less dangerous inmates, around 1830, shared a room with up to five other individuals. The cell furnishings at that time included eating and drinking utensils, a chamber pot, and a shelf. Even in 1851, only seven out of the 25 cells were heated.

By 1870, the cells also had a table, a chair, and a straw mattress, but there was no electric lighting until 1932. Thirty years later, the incarcerated men and women in solitary confinement still had no toilets in their cells. They had to use buckets for their needs. In the 21st century, conditions in the Sennhof improved significantly. The narrow cells now all had running water, toilets, and electricity. In addition, inmates were allowed to smoke, use TV and radio, and subscribe to newspapers.