The construction is of brick and rubble with modern concrete repairs.

A concrete repair on the roof (dating from the 1950s) marks where the tomb was plundered at some unknown time in the distant past.

Once the concrete repairs have set, rebuild the steps, starting from the bottom.

Extensive concrete repairs were done, new walkways added, and a new filtered and chlorinated well water system installed.

The budget document on the city housing authority's Web site says that brickwork, concrete repairs and roofs will require $104 million in 2005 and $103 million in 2006.

The money would be used partly for exterior projects such as brickwork, concrete repairs and roofs, and interior ones such as bathrooms and kitchens.

Microbiologically precipitated calcite has a wide range of applications, such as soil remidiation, soil stabilization and concrete repair.

In 2010, an additional restoration included "cleaning, corrosion removal and stabilization of its ferrous metal elements, compounding of the painted surfaces, concrete repair, and partial repainting".

This work involves concrete repairs inside the tunnels and excavation around numerous manholes or the installation of new manholes to provide better egress from the tunnels.

In some work areas, new egress points have been installed, and these new egresses will be used to access the utility tunnels to complete underground concrete repairs.