The 2011 excavation aimed to define further the dynamics of events pre-dating the construction of building 3000-3001. Work continued in the sectors where structures from earlier phases, mainly USM 3038 and 3037, presented important stratigraphy (trenches C1 and C3).

The work in Trench C1 concentrated on the strip parallel to wall 3000, (a 2008 trench), where a layer of small to medium sized fragmentary, mainly sandstone slabs (US 3095) was uncovered. This can be linked to level US 3090 in the 2009 extension. The pottery was again mainly unglazed coarse ware. During the recording of the level of slabs 3095, a cut (3096) was identified which must have housed the foundations of wall 3000. This narrow slit cut the layer of fragmentary slabs 3095 and the underlying layer (3098 = clay bank). At present, the foundation of wall 3000 is only visible as a single course of squared Alberese blocks of the same type as those in the standing portion of the wall. The blocks were arranged at the base of the part closest to the excavation edge, by curtain wall 3091, that is, where the substratum reaches its lowest level. The foundation offset was not present along the whole of wall 3000, its projecting part gradually reducing, and then disappearing, when the wall reached the bedrock by the corner of perimeter wall 3001 that is, towards the higher part. The narrow cut 3096 also gradually disappeared, probably substituted by the surface created from the bedrock emerging here, while the foundation cut became a narrow cleft in the rock.

In trench C3, situated to the inner side of perimeter wall 3001, the remains of structures post-dating the building emerged, in particular the dry-stone wall 3206. A collapse (3212) extended to the west of this wall.
This sector of the trench, which seemed to slope from north-east to south-west, as already seen in adjacent trench C2, was levelled through the use of small-sized materials and cobbles (3208 and 3204), in order to create an even surface, during the period when the building to which wall 3001 belonged, was in use.

As regards the phase relating to the earliest structure 3206, a surface covered with a layer of ash (3213) was uncovered, almost exclusively extending east of the wall. To its west, where collapse 3212 is still in place, in the northern most part of the trench (which corresponds with the highest part of the excavation), the collapse thinned and a layer of clayey soil emerged, similar to that present below the layer of ash 3213 (US 3221).
Two lenses of ash grey silty soil (US 3215 and 3216) were preserved on this clay surface, 3220, very similar to that of 3213. In one of these lenses there was a small hole (US 3218) filled by the same silty soil with a heavy concentration of ash.