Cleaning &/or Restoring Gravestones

So... you want to clean gravestones and or rehab them. My question to you is... are you crazy? OK, just kidding, it is very rewarding, but do you know what is involved, what to do, what not to do, and more importantly do you know or realize your limitations? These are questions that need to be asked in order to accomplish your task safely for both yourself and for the gravestone. It seems easy, just grab some water, yes; some brushes, perhaps if you have the correct brush; household cleaners, and get to work; no, no, no! Did I already say no?

For starters, the go-to chemical for cleaning gravestones is D2 Biological Solution. It is sold locally in the Albany area; in either one gallon or five gallon containers. It is expensive but it is the only approved chemical for cleaning biological growth off gravestones. Biological growth is moss, mold, or various lichens. Biological growth is not dirt. Dirt may or may not be removed with the use of D2. For actually cleaning a gravestone Orvus soap has been used by other conservators. I have no experience with using Orvus on gravestones. So I cannot speak on cleaning techniques with Orvus.

Before I decide to clean a gravestone the first thing that I do is look the stone over and ask myself the following questions. Does the stone really need to be cleaned? I do not simply clean every gravestone that is discolored. Only ones that are illegible and those that require repair are what I clean with D2. Is the gravestone damaged? If it is broken, can I easily handle it? During the inspection ask yourself this question, will I damage the stone more than it already is if I attempt a cleaning? If the answer is yes, leave it alone. Do not mess with it. Leave it to the pros. Most important, if I start working on this stone will it fall and possibly on me? If the stone is large always position your body away or on the side of the stone so that if it does fall it will not land on you.


Regarding damaged gravestones, the photo below shows what is known as delamination. Delamination occurs when weathering opens and a weak spot forms where the the outer layer of the stone begins to separate and flake off in layers. Do not attempt a repair on this unless you are a professional.

Photo courtesy gravestonematters.org.uk

Cleaning with Clorax is a huge no no. Clorax will damage the stone because it is a caustic chemical. Salts within the Clorax will soak into the porous stone, especially marble, and begin to eat away at the stone. This reaction will cause damage known as sugaring. Below is an example of sugaring.

Photo courtesy Internet search

Moss, lichens, and other plant growth that enter small cracks in the stone will also eventually cause more damage with the roots digging further into stone which will allow for water to enter the opening and begin a freeze thaw process that can break the stone at the crack.

Photo courtesy chicora.org

When repairing a broken stone; in the below picture, the stone is a tablet grave marker from a local cemetery. Notice the incorrect side bracing and what do you think the end result was.

The cleaning process that I use follows as such.

• the stone is first checked for stability and damage (we do not want to incur further damage to the stone)
• if the stone has heavy lichen growth, I begin by gently scraping the growth off with a soft scraper or popsicle stick (we want the stick to wear down and not the stone)
• next the stone is gently scrubbed with water and a soft nylon bristle brush to further remove biological growth
• the stone is then rinsed with clean water from a pump garden sprayer
• D2, poured into a spray bottle is then sprayed on all faces of the stone and allowed to remain on the stone for 15 minutes
• after 15 minutes, with fresh water the stone is again scrubbed with the soft nylon bristle brush
• more D2 may need to be applied and scrubbed in
• the stone is given a final rinse with the pump sprayer
• the stone will definitely be cleaner, but within 3 months time the stone should be noticeably brighter. One thing to remember is that all gravestones are not created equal. Some clean up better than others. Sad but true.

Restoration of gravestones involves various aspects of repair. It depends on how the stone is damaged and what needs to be done for restoration.

Gravestones, especially marble stones can be found in cemeteries in three different manners. First, many of tablet style gravestones are larger than you think. The photo below shows Mary Cline's gravestone. Her stone is almost five  feet long with the majority of the stone buried in the ground for stability. Her stone was excavated, straightened, and back filled with compacted stone dust. Over the period of years her stone began to lean due to gravity and conditions of the soil.

Next to Mary's stone is her husband, Russell. His marble stone is attached to a marble base via pins and mortar. The photo below shows another plot that was in need of attention. The pins and pin holes are clearly visible in the photo.

All three stones in need of restoration
Notice the securing pin & pin holes

Iron pins held the marker to the base and mortar was applied under the stone and around the joint where the stone meets the base. Over time the mortar fails and seems to vanish.

The iron pins are removed because they tend to rust and oxidize which causes the pin to expand and this can cause the stone to break. Have you ever notices rust like discoloring and upward cracks on the stone just above the base. That is from oxidation. The iron pins are replaced with stainless rod that is cut to length and secured with a special type of lime mortar called Lithomex. The Lithomex is placed under the stone and also pointed around the joint where the stone meets the base to seal the joint.

Notice the Lithomex seal around the base of the stone

Lithomex is porous and allows the stone to "breathe." Never repair gravestones with Portland cement. Repairs with Portland cemetery can further damage the stone because Portland is much harder and stronger than marble and lime gravestones which will cause the gravestone to break and not the Portland. When a stone is repaired with lime based Lithomex the repair will break if needed and not the stone itself.

The third way that marble stones are found in cemeteries is in the mortise and tenon or tab and socket method. This is where either a small "tab" in the center of the stone fits into a slot in the center of the base or the whole tablet fits into a large slot in the base. Below is a photo of a base where the tablet fits into the slot.

This large stone below did not have a base. For some reason the base was gone and only way to keep the stone upright was to fabricate a new base. Making a new base is relatively easy. Cement, 2 x 6s, screws, and insulating foam is all that I use. The foam is cut to custom width and depth according to the size of the stone. When the base is cured the foam is removed and you have a slot where the stone can be inserted. The slot is slightly larger than the stone and is partially filled with the lime based mortar. After the stone is inserted the joint is sealed with additional Lithomex.

Fabricated new base

Putting broken gravestones back together can be a process, especially if much of the stone is missing. The epoxy that I use is Akemi Akepox 2030. It is a two part epoxy that is very strong. Not much is needed to make repairs. Just dab along the break line, secure with clamps, and then infill with Lithomex to fill and hide the crack.

Original condition
Gravesite of my great great grandfather's sister

Initial cleaning and epoxying

Broken stone attached to base

More expoxying and clamping

Before final crack infilling

Finally, gravestones are heavy. Some are light enough that they can be picked up and set in place by hand and some cannot. Therefore mechanical means are necessary to safely lift a stone in place. Below is an example of a stone that was too heavy to lift; so the tripod, hoist, and soft nylon straps were brought in to safely make needed.

As a final note, when attempting this work, be safe, do the right thing, have fun, and enjoy!

For further information on cleaning or restoring gravestones, please see:

Online Sources
Association for Gravestone Studies
Cemetery Conservators for United Standards
Chicora.org
Iscga.org

Print Sources
Strangstad, Lynette. A Graveyard Preservation Primer. New York: Altamira Press, 2013
Jones, Melanie S. Aspects of Stone Weathering, Decay and Conservation. London: Imperial College Press, 1997