The maintenance works of Ilios Melathros began in 1985, one year after the concession of the building to the Ministry of Culture. The purpose of this work was to maintain and restore the building after the alterations and damage it had suffered.
The problems encountered by the maintenance crews were varied. In most places the murals and ceiling paintings were covered by successive layers of thick paint, wood and plaster decorations or wallpapers. Some surfaces were painted and the original paintings were embroidered, for example nude figures were dressed in clothes.

The mosaic floors had been damaged (detachments, loss of tiles and mortar, creation of cracks and gaps) that had been roughly treated with cement additions or covered with carpets and rugs.

The wooden elements (doors, windows, frames and handrails) were covered with layers of oil paint in several cases, thus eliminating the original painting imitation of wood and marble.

The metal elements (railings, lamps, metal stairs) were also covered with layers of oil paint.

The marble surfaces (stairs, columns, balconies, handrails, pillars) had suffered the wear of time (dust, soot, etc.) with sugaring on the external surfaces and color changes from the corrosion of metal joints.

The maintenance of the murals-ceilings began with the removal of all the interventions and the subsequent painting, so as to reveal the original surfaces.
The process was laborious and time consuming, due to the large thickness of the coating layers.
This was followed by the cleaning of the surfaces and fixing works of the painted surface. Where there were cracks or losses of the mortar, additions were made and finally the aesthetic restoration works were carried out.
The plaster thorns , which are located around the perimeter of the ceiling of each room and which also served as air ducts, were discovered, supplemented, where there were losses, and those that were damaged were replaced with exact copies.

The mosaic floors were first cleaned of all kinds of deposits, to reveal the decorative patterns. The cement fillings were removed and the fillings were made with the appropriate mortar. The joints were cleaned and tiles were placed, where there was a loss.

The wooden elements were revealed, the necessary additions were made to the existing losses and they were restored aesthetically following the original imitation of wood and marble.
The metal elements after being revealed, fixed, completed where necessary and their color rendering was done, according to the original drawings, photos and descriptions of the building.

The marble surfaces were cleaned of all kinds of deposits and color changes of metal joints.