Hidden for more than thirteen centuries and known only from literary sources, the hypogea have recovered their original charm through a major restoration signed Edilerica.

Attention, in particular, has focused on the covered part of the hypogea, used through the centuries as storage. The wall structures had extensive black crusts due to pollution and weathering. The surfaces were then thoroughly cleaned with ammonium carbonate compresses with various application times and subsequent washings.

A second part of the intervention on the same surfaces involved consolidation and integration activities. To this end, different types of grouting mortars were created to best reflect the color and grain size of the various original materials including tuff, peperino, travertine, and brick.

In order to provide clear guidelines for the various restoration teams, a piece of masonry that had all the types of materials described was isolated, grouted with the respective mortars, and made into a working example.

The vaulted ceiling was secured first by removing the degraded material and then by applying steel mesh with curvatures following the vault. The floor, in theOpus Spicatum pattern, formed by diagonal herringbone dowels, was in turn washed, biocide treated, and then grouted with mortar similar in color to the original.

The missing floor was reintegrated by laying a cocciopesto mortar, which was similar in strength and color to the floor of
Opus Spicatum
but still distinguishable from the original.