Joe Segal SCUL TURE 2-F
126 Oncida Street, St. Augustine, Florida 32084 (904) 829-6761
Preservation Report for the lions at the foot of
The Bridge of Lions in St. Augustine, Florida
In researching a conservation recommendation for the marble lions, I consulted with Dr. Mary F.
Striegel, Materials Research Program Manager and Elizabeth Bede, Materials Research Program Fel-
low, both of the National Center for Preservation Technology and Training in Natchitoches, Louisiana;
marble conservation expert, Professor Norman Weiss of Columbia University, New York; and Ron
Woods, Chief Engineer of LAW Engineering in Jacksonville, Florida-
Although the surface of the lions is slightly sugared or deteriorated it is to be expected for Carrara
marble which has been outdoors for 75 years. If particles would come off on one's hand when the
marble is rubbed, then sugaring would be of concern and use of a stone consolidant would be recom-
Since the use of even a dilute consolidant such as Prosoco's D-40 could result in eventual yellow-
ing of the stone and since the sugaring of the lions is not severe, a surface treatment is not recommend-
The hairline cracks throughout the statues are of greater concern. These cracks have occurred pri-
marily in the valleys of the carved surface. Whenever a stone is carved, a microscopic fissure occurs in
the valley of the material due to the percusive nature of stone carving.
The intensification of these cracks could have been caused by the salt water which leeches into the
stone and causes a slight expansion and contraction of the materials. Vibrations from vehicular traffic
or the relocation of the lions during the 1980's could also be contributing factors.
Regardless, these cracks result in increased moisture penetration and thus erosion. Automobile
exhaust contains corrosive sulfur dioxide which mixed with rain water is deposited into the stone along
the cracks. Left untreated, the depth and width of the fissures will increase and may cause structural
Because of the hairline width of the cracks, it is assumed that the depth is not yet very profound. If
these are shallow cracks they should be filled with a soft mortar mix of 20% portland cement, 30%
lime and 50% marble dust Due to the slight expansion and contraction of the stone and the relatively
soft nature of Carrara marble, use of any stronger mortar mixes or cpoxies is unadvisable.
Soft mortar mixes are considered sacrificial they would crumble before the marble if there is sig-
nificant movement. Observing the solidity of these fills would be a good way to monitor the stability
of the lions.
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Because of the location of the lions, the high amount of pedestrian traffic around them and their
importance to the city of St. Augustine, further analysis of the cracks is recommended.
Low frequency ultra-sonics could be used to bounce sound waves into the cracks and determine
their depths. A water-based acoustic couplant (such as glycerin) could be used instead of petroleum
jelly since staining the stone is of concern.
If the cracks are found to be deeper than assumed, restoration of the lions would be extensive and a
more comprehensive study of possible remedies would be required.
Before the treatment of cracks is executed a proper cleaning is necessary. Non-ionic detergent such
as Triton-X 100 in a solution of 1 ounce to 5 gallons of water would be the first cleanser used followed
by a similar solution of Vulpex soap. Finally, a mixture of 1 pound dry Calcium Hypochlorite dis-
solved in 4 gallons of warm water would be used on the blackened areas on the undersides of the lions.
Due to the porous nature of the stone, the use of bleach is not allowable.
These blackened areas appear to be biological growth but if they do not respond to the Calcium
Hypochlorite then they might be a gypsum crust. Gypsum crusts occur as Sulfur Dioxide from auto
emissions breaks down the marble into gypsum which is deposited by rain water to the undersides of a
This crust may be able to be removed by gently scrubbing with the cleansers mentioned above. If
the crust is severe, a low-pressure blasting using crushed walnut shells may have to be employed. Reg-
ular sand blasting techniques would be extremely damaging and must not be used.
One final recommendation in preserving the lions is to keep people from climbing on them. Unlike
salt-air, pollution and vehicular vibrations this is an avoidable stress. Whether by use of signage or a
chain barrier, something should be done that would not be visually distracting from the lions.
Although nothing has yet been budgeted for the maintenance of the lions these historic statues must
be preserved. I have therefore included cost estimates as well as a possible source for funding.
To be performed by LAW Engineering
Chemical analysis of black deposits $350
(process of elimination could identify the deposits during the cleaning process)
Low frequency ultra-sonic analysis of the cracks $2500 per day
(probably would take 2 days)
Visual analysis of cracks $1,500
(not necessary if low frequency ultra-sonic analysis is used)