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Conservation Program
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The Trust undertakes a wide variety of conservation projects each year.
The following projects are examples of recent work undertaken by the Trust's conservation team.
Cedar Grove
At the request of the Philadelphia Museum of Art, the Fairmount Park Historic
Preservation Trust undertook the interior restoration of Cedar Grove Mansion in West Fairmount
Park. Given staff constraints, the first step in the restoration process was hiring a consulting
conservator to study the interior finishes of the building. All interior surfaces of the house
were studied, including walls, ceilings, chair rails, window seats, and window sash, frames, and
sills. Based on the evidence uncovered in the study, the consulting conservator, the Trust's lead
conservator, and the curator for the PMA collaboratively determined the appropriate color scheme
for each room.
The Trust's lead conservator for the project implemented the paint analysis by room. All
furniture was removed by specially trained art handlers. The first step in the process was to prepare
the surface for painting, including removing all loose and deteriorating paint and
patching areas of damaged plaster with a specially formulated two-coat plastering system.
Damage to wooden elements was repaired with a flexible wood epoxy. All repaired surfaces were
lightly sanded to ensure proper adhesion of the new paint.
Once the surfaces had been prepared, the conservator, with the help of conservation interns,
applied the paint with natural bristle brushes. The paint selected for the walls and ceiling
was a special latex-based paint designed to give the depth and translucence of whitewash, but
retaining the durability of a latex finish. By applying the paint with brushes rather than
spraying or using rollers, the conservation team was able to recreate the visual impression of
the finish as it would have appeared when originally applied.
Once the paint finishes had been applied, the conservator's attention was turned to the floors.
Although the floors of the building are original to its construction, the existing finish was
applied in the twentieth century, and was both materially and visually inappropriate. The finish
was removed using a chemical solvent and soft bristled scrub-brushes, then absorbed using terry
rags. The process was labor intensive, but allowed the conservator to carefully control the
level of finish removed, and ensure that no damage was done to the wooden floorboards. When
the finish was fully removed, the floors were thoroughly cleaned and vacuumed with a HEPA-filtered
vacuum to ensure that no dust was present prior to the application of the floor finish.
A two-part water-based high-traffic finish was applied. This finish will act as a protective
layer for the floor, but will allow its natural appearance to show through.
The full interior restoration process took nine months to complete. Today, through the
information gleaned through paint analysis and its implementation, the interior of Cedar Grove
is vastly different in character, and its historic interpretation more accurate.
Lemon Hill
Lemon Hill Mansion was constructed in 1799, and is famous for its Federal-style
architecture. These features include a delicate fanlight and sidelights surrounding the front
door, narrow window muntins, and three perfect oval-shaped rooms stacked upon one another.
After two hundred years without incident, a portion of the plaster ceiling in the third floor
oval room collapsed suddenly, leaving a hole approximately four feet by five feet. The Friends of
Lemon Hill, one of the stewarding organizations for the building, immediately contacted the Trust and
requested that we evaluate the situation.
The Trust immediately began working to stabilize the ceiling surrounding the loss. Using screws
with plaster washers, Trust conservators anchored the existing plaster to the wooden lath
structure above. This stabilization measure prevented the surrounding area from collapse.
When the area was stabilized, Trust conservators evaluated the condition of the ceiling from above.
After removing years worth of dirt and debris, it became apparent that the bulges of
plaster that keep plaster attached to the supporting lath (called plaster keys) had broken in
discrete areas. However, the reason for the broken keys was not evident: there was no other
evidence of damage due to water or impact, nor was a design flaw readily evident. Without any
apparent cause of damage visible, the Trust determined that the services of a structural engineer
were necessary to definitively ascertain the cause of failure. After a thorough assessment,
the engineer determined the cause of failure to be simple fatigue. After two hundred years,
many of the plaster keys had broken under the weight of the ceiling they support.
In order to prevent failure of the remaining portion of the ceiling, the Trust conservators
together with the structural engineer designed a treatment to stabilize the remaining portion
of the ceiling. First, the natural sag or deflection in the ceiling was measured and documented.
By documenting the deflection in the ceiling, the conservators provided a baseline from which
future movement in the ceiling can be noted. The conservators then drilled small holes in the
ceiling at 16-inch intervals, secured the plaster ceiling to the joists above using screws and
plaster washers. The screws and washers were countersunk into the ceiling, and concealed with a
thin layer of finish plaster.
To repair the area of plaster loss, the Trust hired a plaster conservator. The plaster
conservator, together with the structural engineer, designed a layer of metal lath to allow future investigators to distinguish
between the modern and historic plasters. He then applied three coats of plaster: a coarse
brown coat, a scratch coat, and a finish coat of plaster, a system substantially similar in
material property to the original. Ultimately, although one small area of the ceiling was lost,
the majority of the ceiling was preserved.
Smith Memorial Playhouse Floor
The Smith Memorial Trust contacted the Fairmount Park Historic Preservation Trust
regarding the floor in the Playhouse Office. Built in 1899, Smith Memorial Playhouse is one of
the largest structures in Fairmount Park, and, as its name indicates, was designed to be used as a
playhouse for the children of Philadelphia. The original wooden floor in the Playhouse office
had been covered with synthetic tile. As the tile was cracking and failing, the Smith Memorial
Trust requested that the Trust restore the original wood floor rather than repair or replace the
failing tile.
The first step in restoring the existing wooden floors was to remove the covering of tile and
its underlayment. The tiles were easily removed mechanically. However, removal of the
underlayment of the floor proved significantly more problematic. After testing the solubility
of the paper-based underlayment, the conservators determined that the paper had been affixed to
the original wooden floorboards using hide glue. This was a common practice prior to the
popularization of synthetic glues in the mid-twentieth century; however, it posed a unique
challenge. The only solvent for hide glues is hot water, which raises the grain of exposed
wood. The conservators were forced to use small amounts of very hot water on small sections
of the floor to quickly dissolve the hide glue; once the glue had dissolved, the conservators
used sharp scrapers to remove the paper underlayment. They used the scrapers with extreme
caution so as not to remove the wood grain below. The water was quickly absorbed using terry
rags to prevent the wood grain from rising.
This process was difficult and tedious, but remarkably effective. When all of the glue and
underlayment were removed, the floor was allowed to dry thoroughly before it was gently buffed with a
conservation-grade sandpaper. All dust and debris were then vacuumed from the floor before a
water-based high-traffic clear finish was applied.
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