The traditional structure was probably part of the village nucleus of Umm Tuba. The building was square (c. 5.3 × 5.3 m) and consisted of a single chamber, topped with a cross vault, that was probably domed, as were several buildings in its vicinity. Only the northern and western walls of the building survived to their original height (c. 3.1 m).
The dome did not survive, but the remains of the cross vault were visible on the uppermost part of the inner face of the walls. The building’s entrance was not preserved; it was probably located in the center of the eastern wall, which did not survive. Although the southern wall of the building did not survive, a window may have been built into it. The walls were constructed of dressed blocks made of soft chalk, and were covered with plaster and modern paint. Three rectangular niches were set into the inner face of the walls: two in the northern wall (length 1.2 m, height 0.7 m, depth 0.5 m; width 1.1 m, height 0.67 m, depth 0.45 m), and a third—with an arched ceiling (width 1.67 m, height 2.15 m, depth 0.46 m)—in the center of the western wall. The building was paved with tiles in the twentieth century. A rock-hewn depression (c. 1.7 × 2.0 m, height 0.4 m), treated with modern plaster and paint, to the east of the building, is part of the building complex.
The cave was elongated along a north–south axis, with an irregular outline (length c. 15 m, width 9–10 m, height 2.2–2.8 m; Fig. 3). A rectangular opening, blocked with concrete was found in its ceiling (length c. 2.3 m, width 1.55 m, height 0.3 m to a modern concrete blockage; Fig. 4). The cave was entered through an opening at the center of its eastern wall; part of a built doorjamb and a built threshold remain of the opening (Fig. 5). The opening was divided by a wall (W101; Fig. 3: Section 2-2), that ran along the center of the cave along an east–west axis. The wall was haphazardly built of large, irregular fieldstones and building stones in secondary use. Both faces of the wall were treated with mortar mixed with straw. A small niche (width c. 0.65 m, height 0.85 m, depth 0.6 m) and small shelves fashioned from mortar were set in the middle of the southern face of the wall. Arched compartments (height 0.25 m, inner width 0.85 m, outer width 0.65 m, depth 0.7 m; Figs. 6, 7) built of mortar similar to that applied to the wall were set in the western part of the southern face; their upper part was broken. These were apparently part of a larger installation, possibly a cupboard known in Arabic as a sida, used to store bedclothes. One of the compartments had a vaulted ceiling with a hole in it (Fig. 8), which raises another possibility: that they were used to store grain. Chunks of similar mortar, but lighter colored, which belonged to installations or other objects. Were found scattered in the cave. A modern wooden panel was attached to one of them (Fig. 9), pointing to the date of the compartments’ construction.
A wall (W102, height and width 0.8 m), built mainly of medium and large fieldstones, runs from W101 on the north to the southern wall of the cave. A similarly built wall abuts this wall on the west (W103). A probe (L108) was undertaken in the northern part of W102. A section of the wall and the floor of the upper level (F1, below) were removed, and the foundation trench of W101 was excavated. No datable finds were uncovered in the probe. The southern part of the W102 (L109) was built using dry construction, and the stones were not arranged in neatly built courses; it was dismantled during the excavation. Straw and finds from the twentieth century CE were discovered between the stones of the wall. The wall divides the southern part of the cave into two main habitation levels (Fig. 10). It is unclear how one moved between the levels; a staircase may ha e connected the two but did not survive. The floor of the upper, western, level (F1), was made of mortar similar to that which covered W101 (Fig. 11). Fieldstones pavers (F2; 0.10–0.40 × 0.20–0.65 m, 3–4 cm thick) were used in the northwest corner of this level. A probe was opened under the pavement (L111; Fig. 3) yielded a fragment of a bowl from the Ottoman period (not drawn) and a metal vessel from the twentieth century CE. Near the pavement was a stone-built shelf (length c. 1.5 m, width 1 m, height 0.4 m; Fig. 12) was situated next to the pavement. The uneven bedrock served as the floor of the lower, eastern, level (Fig. 13). On the floor were sheep/goat droppings, indicating that this part of the cave was used as a den.
The remains in the southern part of the cave seem to reflect the latest activity in the cave, in the second half of the twentieth century. This is evident from the wooden panel incorporated in the mortar and several modern glass bottles (Fig. 14), as well as metal implements that were found inside the cave, including a metal threshing board (Fig. 15).
The northern part of the cave was not excavated; it too was divided into two levels, separated by an intact stone partition. This partition incorporated a staircase that led from the eastern level to the upper, western level (Fig. 16). Rock-cuttings were noted in the northwestern corner of the cave (not drawn). An opening consisting of modern cement, which probably led into another cavity, was located in the western wall of the cave; it was blocked with a stone wall, indicating modern use of the cave. An installation, probably an oven, was built in front of the opening (Fig. 17). Two niches were hewn in the northern wall of the cave (Figs. 18, 19); the niches, left untreated with any plaster, may have served as storage compartments.
The finds in the cave point to the daily household activities that took place here: cooking, storage and dwelling. The use of caves as dwellings was common in the villages of Jerusalem and the Hebron hill country (for example, Havakook 1985; Hirschfeld 1982), the Shephelah, the Judean Desert and on the outskirts of these regions (Etan Ayalon, pers. comm.). When the building was constructed above the cave, it continued to be used for cooking, storage of grains and sheltering livestock. These uses were closely associated with the village’s economy, which was based mainly on agricultural crops and livestock (‘Adawi 2010:136–138). In recent years, the cave was converted to store scrap iron.