The vaulted plaster ceiling on the second floor of the Natural History Museum had suffered serious water damage over a number of years and was in dire need of architectural conservation. While several attempts had been made to repair the damage, the leak would return and further damage the ceiling and the repairs. At one time one of the coffer panels had become so damaged that it had been removed and replaced with a heavy plaster section. Subsequent water infiltration weakened this repair and it fell to the floor, taking much of the surrounding plaster with it.

The conservation and re-surfacing of the damaged, but in situ, decoration was accomplished by removal of the damaged plaster, consolidation of the remaining sound plaster with and acrylic bonding agent and re-creation of the design. This took several applications and the creation of tools shaped to the profile of the plaster decoration, the result was then primed and painted with a custom matched acrylic paint.

The re-creation of the missing coffer panel proved to be more of a challenge. The ceiling was actually hollow, which meant that any replacement could not be very heavy. It also had to be secured in such a way that it would not put too much pressure on the surrounding coffers, since all had been somewhat compromised by the water infiltration.

The solution was to fabricate a frame and base for the coffer out of thin plywood. This allowed the moldings to be applied to the inner sections without the build-up of very much weight. Using this system it was also possible to attach this coffer to the wire lath substrate so that the substrate rather than the ceiling that held this coffer in place. Once installed the outermost molding could be formed, sealing the coffer in place. It was then finish sanded and painted.