Lara Thomas sank the long, thin probe into the earth to a depth of about 6 inches before hearing the telltale clink of metal on rock.
Thomas repeated the process several times, testing an area of about 1 square foot until the probe sank deeply with no resistance.
She searched for the underground base of a crooked marble headstone in St. Paul’s Union Cemetery. The probe let them know where to dig safely without damaging the rock’s base.
Thomas, secretary of the Berks County Association for Graveyard Preservation, and Karla Hummel, the organization’s second vice president, led a workshop on gravestone repair and preservation at the Mertztown Cemetery last month.
“A lot more people are going (through) cemeteries, cleaning and trying to fix old headstones,” Thomas said, “sometimes with really damaging consequences.”
Videos on social media and other sites often show amateurs trying to clean or preserve old tombstones, she said.
“Unfortunately, not all methods are safe or correct,” she said, noting that some can escalate the degradation of breakable markers or damage them entirely.
Hosted by the Longswamp Township Historical Society, the program was intended to educate genealogists, hobbyists, and others about the proper methods of preserving and repairing ancient headstones.
More than half of the approximately 20 participants were connected to church cemeteries.
Thomas and Hummel began with a slide presentation at the Christian Congregation Church, formerly St. Paul’s, before heading outside to the churchyard for hands-on demonstrations.
The church was built in 1837 and many of the graveyard’s old marble stones are damaged or decayed.
Marie Maly, a member of the church’s consistory and president of the Historical Society, said she has teamed up with other volunteers to repair and preserve the tombstones, but the group doesn’t know where to begin.
“It’s so sad,” she said. “It’s overwhelming for me to look at.”
She asked the Conservation Society for help, and Hummel and Thomas came to the rescue, offering pointers and advice.
Stone is severely damaged by the environment alone and the effects of rain, snow and freeze-thaw cycles, which can lead to erosion, cracking and crumbling, Thomas said.
Natural ground movements and animal burrows can cause the rocks to shift, sink, tilt, or break and fall over.
Other damage is caused by falling trees and branches, stray vehicles, vandals and neglected maintenance. Mowers and trimmers can hit the rocks or kick up pebbles, which can cause damage.
“Sometimes we love our graveyards to death when we mow and trim,” Thomas said.
Many of the 18th- and early 19th-century tombstones remaining in Berks are made of soft, porous stone, particularly sandstone and marble, Hummel said.
Erosion on the surface of these stones creates a granular, or sugary, appearance as the stone crumbles, she said.
Harsh detergents and brushing or rubbing the stone can make the damage worse.
Only very soft pet hair brushes should be used with or without water to gently remove dirt and other particles, Hummel said.
Avoid scrubbing or rubbing, she said, which can be particularly damaging to soft and porous stones and can result in the loss of carved detail and inscriptions.
Soap is generally not required, but if used, it must be of a gentle, pH-balanced kind.
A gentle biocide called D/2 has been approved by the National Park Service and can be used to remove organic growth, she said. The biodegradable cleaner is pH neutral and contains no salts, bleach or acids. It is sprayed on and left to work.
If grout is required use only a hydraulic lime based product. Never use portland cement, concrete or any other hard mortar. Such products remain rigid as the stone expands and contracts with temperature, causing the stone to crack.
Cracked stone can be repaired with a clear stone epoxy, alone or mixed with marble or sandstone dust.
While the biocide and epoxy can be expensive, Thomas said, most of the tools needed can be found in a typical homeowner’s garage or borrowed from friends and neighbors. Spades, crowbars and spirit levels are usually all that’s needed to reset a fallen rock, she said.
The program and demonstration gave Maly and the others direction and made gravestone restoration less daunting.
“It’s possible and it’s not that difficult,” said Maly. “It just takes people willing to do it.”
For more information or to volunteer with the Berks County Association for Graveyard Preservation, visit www.bcagp.org.
For more information or to volunteer with the Longswamp Township Historical Society, visit www.longswamphistory.org.