According to Fiorelli, this shop had a staircase, a latrine and a rear room.
See Pappalardo, U., 2001. La Descrizione di Pompei per Giuseppe Fiorelli (1875). Napoli: Massa Editore. (p.92)
According to Eschebach, the stairs to the upper floor were on the right, the rear room was in the south-west corner, on the right at the rear.
The down pipe from the latrine on the upper floor was in the south-east corner, on the left at the rear.
See Eschebach, L., 1993. Gebäudeverzeichnis und Stadtplan der antiken Stadt Pompeji. Köln: Böhlau. (p.279)
Photo courtesy of Michael Binns.