In 2005, the project’s work concentrated on the northern parts of the Casa di Marco Lucrezio. Excavations were continued in the garden and several waste pits containing mostly wall painting fragments and some pottery were discovered. The Fourth Style painting fragments found at the bottom of one of the pits next to the fountain complex date the deposit to the last phase of Pompeii and confirm the late date of the visible garden arrangement. The trench by the pappamonte wall in the southern part of the garden was extended, but only two new later waste pits were discovered.

Buildings archaeological work was extended to the house IX 3,24 where excavations were carried out in two places in the atrium and in the area between the garden and house 24. A sequence of three plaster floors was discovered in the northern atrium and the same sequence was also found in the southern trench. The fill layers between the floors raised the general ground level ca. 50 cm possibly causing also changes in the walls, which had to be raised as well. The finds from the contents of a large waste pit – or possibly a filled cistern – in the middle of the atrium under the lowermost floor dates the beginning of the sequence only roughly to the 1st century BC. Some 3rd–4th century BC pottery was discovered in the southern trench just above a sequence of layers of volcanic ash.