Being asked to clean and assess the Tomb ofthe Unknowns, is a project we at Ponsford Ltd hold with the greatest pride, and a privilege, that we have had the honor to perform four times.
To begin with, we take numerous photos of the entire monument and perform a written assessment to document the condition, before any work commences. This is then compared to the previous assessment to determine if any changes have occurred since the last time. The acid rain in the Washington D.C. area is unrelenting. Pollutions that are allowed to build up on the surface, is the number one cause of deterioration to stone. When rain comes in contact with the sulfur and other pollutants that have settled on the monument, it produces an acid that is destructive to the surface. To avoid this from occurring Arlington National Cemetery takes the preventive maintenance approach with an annual cleaning. This process allows for minimal intrusion on the monument. The entire surface is hand washedusing a soft brush with a neutral ph cleaner and rinsed with clean water onlow-pressure. This is always the preferred method over waiting for a monumentor sculpture to show corrosion or deterioration before addressing it.