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48 PRESERVATION

BRIEFS

Preserving Grave Markers in 

Historic Cemeteries

Mary F. Striegel, Frances Gale, Jason Church, & 

Debbie Dietrich-Smith

National Park Service

U.S. Department of the Interior

Technical Preservation Services

Cemeteries found across the country are not only 

places of burial, but they also provide a vivid record 

of community history. Whether large or small, well 

maintained or neglected, historic cemeteries are an 

important part of our cultural landscape. The vast 

richness of expression through form, decoration and 

materials informs our understanding of the individuals 

buried in historic cemeteries and their cultural 

signifi cance. 

While cemeteries are often considered to be perpetual, 

their most prominent feature—the grave markers—

are not. They weather, naturally decay, often are 

poorly maintained and repaired and, on occasion, 

are vandalized (Fig. 1). Grave markers are usually 

noteworthy not only for their inscriptions but also for 

their craftsmanship. Exceptional markers are considered 

works of art. 

This Preservation Brief focuses on a single aspect of 

historic cemetery preservation—providing guidance 

for owners, property managers, administrators, inhouse maintenance staff , volunteers, and others who 

are responsible for or are interested in preserving and 

protecting grave markers. Besides describing grave 

marker materials and the risk factors that contribute to 

their decay, the Brief provides guidance for assessing 

their conditions and discusses maintenance programs 

and various preservation treatments. 

Also identifi ed are a number of excellent references that 

address materials used in all grave markers, including 

several other Preservation Briefs (listed in Additional 

Reading). This Brief highlights particular issues that 

should be considered with historic grave markers. 

Types of Traditional Grave Markers

The great variety in the types of grave markers is a 

fascinating aspect of the study and appreciation of 

historic cemeteries. Three broad categories can be used 

to describe grave markers—(1) single-element, (2) 

multiple-element, and (3) structures. Single-element 

grave markers are stone, cast iron, or wood elements 

that are set in a vertical position or placed as a horizontal 

slab on the ground (Fig. 2). Early examples of this 

simplest type of grave markers are fi eld stone and basic 

wooden or wrought iron crosses, with the name of the 

deceased person scratched into or engraved on the 

marker. Often, these rudimentary grave markers are 

overlooked, signifi cantly deteriorated, or lost. Vertical 

stone slabs and large stone ledgers laid horizontally over 

the gravesite are more sophisticated examples of this 

type. 

Multiple-element grave markers are found in a number 

of diff erent forms (Fig. 3). In the most typical form, a 

grave marker would consist of two stones—an upper 

headstone placed on top of a base stone. The upper 

headstone may be secured in a number of diff erent ways 

to the base. In the simplest of forms, the upper stone was 

placed on the base, set in a bed of mortar on top of the 

base, or joined with pins and mortar. With a “tab-andFigure 1. Sandstone and slate grave markers in the Ancient 

Burying Ground in New London, CT, display a variety of weathering 

conditions. Markers in the cemetery date from the mid-17th to the 

early 19th centuries. Photo: Jason Church.
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slot” grave marker, the tabbed upper stone was set in a 

slott ed base. More common today, the upper headstone 

is secured with a technique that uses small spacers set 

on the base and a sett ing compound. This technique or 

one that uses an epoxy adhesive may be found on older 

markers where the stones have been reset.

Stacked-base grave markers use multiple bases to 

increase the height of the monument and provide a 

stable foundation for upper elements. Tall, four-sided 

tapered monuments, known as obelisks, are typically 

placed on stacked bases. Columns or upright pillars 

have three main parts – a base, shaft, and capital. 

Multiple-element grave markers may also include 

fi gurative or sculptural components. Traditionally, 

stacked base grave markers were set on lead shims with 

mortar joints or with lead ribbon along the outer edges. 

Grave markers can also be engineered structures. 

Examples of grave marker structures include masonry 

arches, box tombs, table tombs, grave shelters, and 

mausoleums (Fig. 4). The box tomb is a rectangular 

structure built over the gravesite. The human remains 

are not located in the box itself as some believe, but 

rather in the ground beneath the box structure. The 

table tomb is constructed of a horizontal stone tablet 

supported by small corner supports or columns. 

Grave shelters, also called grave houses, can be 

simple or elaborate wooden structures built over the 

gravesite. Mausoleums are above-ground buildings 

with compartments for multiple burials. Engineered 

structures also include hillside and underground tombs. 

Guidelines for Evaluating and Registering Cemeteries 

and Burial Places, National Register Bulletin 41, provides 

a concise review of grave marker types. 

Materials

Stone, brick, concrete, metal, and wood are the most 

common materials used for grave markers and for fences 

and gravesite enclosures in historic cemeteries. This 

section briefl y describes the composition and properties 

of these diverse materials

Masonry materials 

There is a wide variety of masonry materials used 

in historic cemeteries; some are naturally occurring 

and others man-made. Although there are notable 

exceptions, most masonry materials are durable, 

have high compressive strength, and are resistant to 

weathering. As grave markers, they typically represent 

the work of masons and stone carvers.

Stone is a naturally occurring material with a wide 

range of properties and is available in a variety of colors 

(Fig. 5). Geologists classify stone according to the way 

in which it was formed with the three categories being 

igneous, sedimentary and metamorphic rock. Stone 

found in cemeteries is predominantly quarried, though 

the use of fi eld stones is not uncommon. The mineralogy 

and chemical composition of stones vary. Some are 

composed primarily of silicate minerals; granites, 

sandstones, slate, and schist are examples. Other stones 

contain calcium carbonate with marble and limestone 

in this group. Mineralogy, chemical composition, and 

physical structure of the stone infl uence weathering and 

Figure 2. These mid-19th century, single-element stone grave markers 

in the Grove Cemetery in Bath, NY, are set in a vertical position. 

Photo: Jason Church.

Figure 4. This sandstone table tomb, located in Cedar Grove 

Cemetery, New London, CT, is an engineered grave marker structure 

consisting of a horizontal stone tablet supported by four vertical table 

“legs” with and a central column,. Photo: Jason Church.

Figure 3. A multi-element grave marker 

from the early 19th century in the St. 

Michael’s Cemetery, Pensacola, FL, 

consists of a vertical element with tabs 

(left image) into a slott ed base (right 

image). Photo: Fran Gale.
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the selection of materials and procedures for its cleaning 

and protection. 

Man-made masonry materials are manufactured from 

naturally occurring raw materials. For example, the raw 

materials used to make brick include clay, sand, and 

shale. During fi ring, clay minerals and sand melt and 

come together forming silicates, aluminates, and metallic 

oxides. The resulting brick material has a hard-fi red 

outer surface with a softer interior. 

Concrete is a man-made material composed of cement, 

sand, gravel, and water. Most concrete produced after 

1870 contains Portland cement, another manufactured 

product. In its plastic or wet state, concrete can be cast 

or poured. It hardens by hydration, a chemical-curing 

process. The resulting product has excellent compressive 

strength, but much lower tensile strength. Reinforcing 

concrete with steel helps compensate for this limitation. 

All masonry materials are porous with an interior 

network of pores. The porosity of sedimentary rocks 

such as limestone and sandstone can be as high as 20 

percent while the pore volume of granite is very low. 

Because moisture is a key factor in many deterioration 

processes, porous masonry materials are more 

vulnerable to weathering. 

Metals 

Metals are solid materials that are typically hard, 

malleable, fusible, ductile, and often shiny when new 

(Fig. 6). A metal alloy is a mixture or solid solution 

of two or more metals. Metals are easily worked and 

can be melted or fused, hammered into thin sheets, or 

drawn into wires. Diff erent metals have varying physical 

Figure 5. A variety of colors of natural stone are found in historic 

cemeteries, such as this pink granite marker in the Cedar Grove 

Cemetery, New London, CT. Photo: Jason Church.

Figure 6. Decorative cast-iron grave markers like this late-19th 

century one in Oakland Cemetery in Shreveport, LA, are produced 

by heating the iron alloy and casting the liquid metal into a mold. 

Photo: Jason Church.

and mechanical properties, aesthetics, and weathering 

characteristics. 

Ferrous metals and alloys, including cast iron, wrought 

iron, and steel, all contain iron. Cast iron also contains 

carbon and silicon and has a relatively low melting 

point. When heated to a liquid state, it can be molded 

into a variety of shapes. Wrought iron is an alloy with 

low carbon content. Its fi brous inclusions (called slag) 

are sometimes visible to the naked eye. Unlike cast iron, 

wrought iron is heated to the point where it becomes 

soft and then is hammered or “worked” into desired 

shapes. Most of the wrought and cast iron in historic 

cemeteries is ornamental rather than structural. While 

cast iron, steel, and wrought iron all contain iron, steel 

and wrought iron are more resistant to corrosion. Paint 

was often applied to ferrous metals to help protect them 

from corrosion and for decorative purposes. Metal 

elements were painted in a variety of colors including 

black, white, and green, among others. 

Nonferrous metals and alloys, such as bronze, zinc, and 

lead, do not contain iron. Bronze contains about 85% 

copper, 10-15% tin, and sometimes lead. Historic bronze 

cemetery markers were created by casting processes 

that involves pouring liquid bronze into a mold. The 

completed casting is hollow. Bronze work may comprise 

a single molded component, such as a plaque, or 

multiple molded components welded or fitt ed together 

as with large statuary. Chemical patinas were applied 

to enhance color, and clear coatings for protection. 

Cast zinc monuments were popular from 1870 through 

the early 20th century. Most cast zinc is bluish-gray in 

color. Although cast zinc is resistant to corrosion, it is a 

britt le material with a tendency to “creep” or deform, 

especially when exposed to high outdoor temperatures. 

Wood 

Wood is a porous organic material composed of 

tubular cells in a parallel arrangement. The structure 

and characteristics of these cells determine the wood’s 
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appearance and infl uence wood properties. Woodcell walls and cavities contain moisture. Oven drying 

reduces the moisture content of wood. After the drying 

process, the wood continues to expand and contract with 

changes in moisture content. The loss of water from cell 

walls causes wood to shrink, sometimes distorting its 

original shape (Fig. 7).

Hardwoods come from deciduous trees such as oak, 

maple, and walnut; softwoods from conifers such as 

pine, cedar, and fi r. In general, hardwoods have higher 

density than softwoods, which makes them more 

durable materials, and are darker in color. Wood cut at 

diff erent orientations aff ects its strength and weathering. 

As an organic material, wood is also particularly 

vulnerable to termites, carpenter ants, and other wooddestroying insects and fungi. Paints, coatings, and 

fungicides such as borates are used to help protect wood 

from various insect damage and fungal rot. 

Other materials 

Old cemeteries often include a wide variety of other 

materials not normally associated with contemporary 

grave markers, such as ceramics, stained glass, shells, 

and plastics (Fig. 8). As with masonry, metals, and 

wood, each has its own chemical and physical properties 

which aff ect durability and weathering. These materials 

present unique challenges and their properties must be 

understood before establishing appropriate maintenance 

and repair. Documentation of unusual materials is 

critical when repair is not possible. 

Weathering

All grave marker materials deteriorate when they are 

exposed to weathering such as sunlight, wind, rain, high 

and low temperatures, and atmospheric pollutants (Fig. 

9). If a marker is composed of several materials, each 

may have a diff erent weathering rate. Some weathering 

processes occur very quickly, and others gradually 

aff ect the condition of materials. Weathering results in 

deterioration in a variety of ways. For example, when 

exposed to rainwater some stones lose surface material 

while others form harder outer crusts that may detach 

from the surface. 

Figure 7. As shown by this 1877 marker in Silver Terrace Cemetery, 

Virginia City, NV, exposure to sunlight can damage wood grave 

markers, making the wood more susceptible to water damage and 

cracking. Photo: Jason Church.

Figure 8. A fi red ceramic, this cameo is set in a marble grave marker, 

located in Elmwood Cemetery, Memphis, TN. Diff erent materials 

may require diff erent conservation approaches. Photo: Mary Striegel.

Figure 9. The limestone and sandstone grave markers in this 

historic cemetery have diff erent weathering processes. On the left, 

the limestone shows surface loss in areas exposed to rainwater and 

gypsum crust formation below. The sandstone marker on the right 

displays uniform soiling, but surface hardening may be occurring. 

Photo: Fran Gale. 
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Granite is a durable grave marker material considered 

resistant to weathering. It is a compact, hard rock 

with low porosity, and granite deterioration can 

be imperceptible for many years. Slate also has 

low porosity, but its layered structure can result in 

delamination. Some stones used to make grave markers, 

like sandstone, limestone and marble, are softer than 

granite and more porous. These materials are more 

vulnerable to weathering with deterioration noticeable 

during the initial years of exposure. With slate and other 

stones with layered structures, weathering sometimes 

results in delamination, defi ned as the separation 

of layers along bedding planes. Diff erent rates of 

weathering are related to the chemical composition and 

physical structure of the material. 

Deterioration aff ects other grave marker materials 

in diff erent ways. With brick, durability is related to 

its fi ring temperature, which infl uences the brick’s 

compressive strength and absorption. Brick fi red at high 

temperatures has a protective fi re skin. The weathering 

of concrete also is variable, and largely depends on 

the materials used in its manufacture. For example, 

Portland cement concrete is generally more resistant 

to weathering than lime concrete. With wood, grave 

markers fashioned from heartwood (the dead inner 

wood) are more durable than those of sapwood (the 

living exterior wood), and some wood species such as 

cedar, Osage orange and black locust contain extractives 

that provide decay resistance. 

The term “inherent vice” is used to describe a material 

with a naturally occurring problem that leads to 

premature deterioration (Fig. 10). An example of this 

problem is marble that has cracked due to natural 

locked-in stresses. Inherent vice also describes grave 

markers that are composed of incompatible materials, 

where decay is accelerated in one or both materials 

because of chemical interactions caused by their close 

proximity. An example is the galvanic corrosion that 

occurs when dissimilar metals, such as copper and iron, 

are in contact and exposed to moisture. 

Risk Factors

There are two major categories of risk factors that can 

impact historic grave markers. The fi rst comprises 

naturally-occurring deterioration phenomena known 

as the forces of nature, including weathering. The 

list of natural risk factors includes climate, biological 

issues, and natural hazards such as fi re and fl oods. 

The other category includes the many degradation 

phenomena that are related to human activities. The 

results of humans and their actions include pollution, 

lack of maintenance, inappropriate repairs, arson, 

and vandalism. While some of the factors related to 

human activities, such as improper repair, may not be 

intentional, the results can be just as damaging to grave 

markers. 

Figure 10. The sandstone cross (carved to look like wood) in this 

grave marker in St. Michael’s Cemetery in Pensacola, FL, provides 

an example of inherent vice – the severe delamination aff ecting 

the sandstone has occurred along its natural bedding planes. 

Photo: Fran Gale.

Often, it is not possible to separate natural risk factors 

from those related to human activities. For example, 

pollution is deposited on grave markers by rain and 

other forms of precipitation, resulting in discoloration 

and often material degradation. Whether due to natural 

risk factors, human activities or both, “synergism” 

occurs when the result of two or more risk factors 

is greater than the sum of the individual eff ects. An 

example is the damage that occurs to salt-laden masonry 

materials during freeze/thaw cycles. The combined eff ect 

of these two deterioration factors is severe.

Natural Risk Factors 

Climate plays an important role in weathering processes. 

Depending upon the climate, cemetery grave markers 

are exposed to rain, snow, sleet, ultraviolet (UV) light, 

humidity, high and low temperatures, and wind. All of 

these forces can damage masonry, metals, and wood. 

For example, with wood, the UV rays present in sunlight 

accelerate the weathering process.

Exposure to repeated changes in temperature can 

have an adverse eff ect on materials such as stone and 

other porous masonry. High temperatures deteriorate 

and weaken many materials while low temperatures 

cause materials to become britt le. In some climates 

there are rapid changes during spring and fall that 
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Vegetation Management

Carefully monitoring and managing of trees and other 

vegetation is an integral part of a cemetery preventive 

conservation program. Mature trees and ornamental 

shrubs can add character, shade, and seasonal color to 

historic cemeteries (Fig. A). However, if not properly 

maintained, they can damage grave markers, fencing, 

and other historic features. Mature trees may fall during 

storms and drop large limbs that topple grave markers 

and mangle fencing. Overgrown vegetation creates wet, 

shaded areas and fosters biological growth than can 

accelerate deterioration of stone, iron, and wood objects.

A treatment plan for cemetery vegetation should 

address trees, shrubs, vines, and “volunteer” 

growth. For the assessment and treatment of trees 

that pose hazards, consult an International Society of 

Arboriculture (ISA) certifi ed arborist. Prune trees and 

shrubs adjacent to grave markers to allow air circulation 

and light penetration. Certifi ed arborists and master 

gardeners should carry out this work or direct others 

in pruning trees and shrubs, as many may be historic 

features integral to the cultural landscape and worthy of 

preservation. 

Regarding lawn care, historic cemeteries were not 

designed for today’s large riding lawnmowers, yet this is 

the mower of choice for many cemeteries, as mowing is 

one of the most time-consuming and costly maintenance 

tasks generally undertaken. Mowing between tight 

spots with a large riding mower deck is destined to 

cause damage. Best practices include using a smaller, 

push mower between particularly sensitive features, and 

outfitt ing riding mower decks with protective bumpers. 

Low-cost options include using fi re hose padding or a 

foam swimming ‘noodle’ (Fig. B). Additional damage is 

caused by riding over low stones or coping, especially 

when the blade height is set low. If rolling over these 

features is unavoidable, many riding mowers have a 

hand-control adjustment to temporarily raise and lower 

the blade height. 

Improper use of a string-trimmer is also 

potentially destructive, especially when it comes 

into contact with soft materials such as marble, 

limestone, and wood. Using the lightest trim 

line and angling the trimmer head towards the 

ground will help reduce damage if the trimmer 

hits unintended targets. Consider hand trimming 

around the most signifi cant, fragile features. 

As a time-saving measure, herbicides are 

sometimes used around the base of features 

to remove unwanted grass and weeds. In most 

cases, use of herbicides for this purpose is not 

recommended, as salts within the herbicide can 

wick into the stone (especially soft stones) and 

cause spalling and deterioration. The removal of 

vegetation also exposes soil around the base of the 

grave marker, which, in a heavy rain, can cause soil 

splashing that may result in staining.

If fertilizer is applied, choose a natural organic 

fertilizer to minimize salt content for the reasons 

stated above. For any chemical application, be sure 

to rinse away residue from grave markers, etc., with 

water using a low pressure hose or spray bott le, to 

minimize continued contact.

Ongoing maintenance of cemetery vegetation is 

essential to conserve grave markers and fencing. 

Periodic inspections may warrant removing 

trees; trimming tree limbs, shrubs, and vines; and 

removing volunteer vegetation. All trees should 

be inspected at least every fi ve years. Annual 

inspections are necessary to assess the condition of 

shrubs and vines, and to identify volunteer growth 

for removal. Mowing and trimming around the 

hundreds of stone, brick, iron, and wood features 

found in many cemeteries is a weekly or bi-weekly 

chore. Lawn care is the most time-consuming, 

and, if not done carefully, potentially destructive 

maintenance activity in historic cemeteries. 

Figure A. Cemeteries are cultural landscapes made up of a 

variety of features. Grave markers are but one component of 

cemeteries that also include walkways, drives, fences, coping, 

trees, shrubs, and other vegetation. Each component adds to 

the understanding of the cemetery landscape. Photo: Debbie 

Dietrich Smith.

Figure B. A pool 

‘noodle’ can be 

fitt ed to the deck 

of a lawnmower 

to prevent damage 

to grave markers. 

Photo: Debbie 

Dietrich Smith.
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cause damaging cycles of expansion and contraction. 

Adjacent dissimilar materials may respond diff erently to 

temperature changes, resulting in distortion. High winds 

can carry water and abrasive particles causing abrasion 

and erosion, especially to soft materials. Wind may also 

drive rain water into masonry joints and permeable 

elements and materials. 

Water, in liquid, solid or vapor form, plays a critical 

role in the deterioration process. Most grave marker 

materials are porous, and moisture from precipitation, 

ground water, or frequent landscape watering can enter 

the pore system. If temperatures drop below the freezing 

point, water in interior pores, joints and cracks freezes, 

and its increased volume often applies internal pressure, 

resulting in damage to the grave marker such as cracks 

or spalling. 

Ferrous metals are particularly vulnerable to waterrelated deterioration. Iron increases in size when it 

corrodes, sometimes as much as 20 percent. As the 

corrosion process proceeds, the ferrous metal eventually 

weakens. When embedded within concrete or masonry 

materials, the corroding iron often causes cracks and 

spalls in the masonry. 

Woody vegetation can damage grave markers in a 

variety of ways (Fig. 11). Trees, bushes, and vines 

can shade grave markers, extending the time that the 

markers are exposed to moisture. Tendrils and roots 

may burrow into mortar joints and openings, causing 

mechanical damage and large plants may lift up or shift 

markers. Even leaves and twigs, when allowed to collect 

on the ground near grave markers, can aff ect water 

drainage and evaporation (Fig. 12).

Microorganisms such as algae, fungi, and lichens 

may aff ect grave markers. Microorganisms hold in 

moisture and some produce acids. With acid-sensitive 

materials such as limestone and marble, the result 

is surface erosion. Sometimes the organisms use the 

material as a food source, dissolving minerals in the 

stone and att acking the cellular structure of wood. 

Wood is especially vulnerable to fungi, algae, and other 

microorganisms when its moisture content is above 25%.

Infestation by termites, carpenter bees and ants, and 

other insects can aff ect the appearance and structural 

integrity of wood. Unsightly bird droppings can also 

aff ect paint and other surface fi nishes.

Human Activities 

Aside from vandalism and purposeful neglect, most risk 

factors att ributable to human activity are unintentional. 

Sometimes damage to grave markers is the result of 

cleaning or repair done with the best of intentions. These 

unfortunate mistakes can be the result of insuffi cient 

training and funding, misuse of tools and equipment, 

and poor planning. With proper training and 

supervision, human risk factors can be lessened.

Figure 11. Woody vegetation can damage grave markers and 

pose a risk to visitors unless well managed and maintained. 

Photo: Jason Church.

Deferred maintenance usually accelerates the 

deterioration of grave markers and can be a safety 

hazard. All materials have a service life with mortar, 

paints, and other coatings requiring periodic upkeep 

to be eff ective. For example, unless ferrous metal has a 

sound protective coating, exposure to weathering can 

result in corrosion. Loose, misaligned or detached grave 

markers may lead to further damage or deterioration if 

not corrected in a timely manner. When nearby trees 

and shrubs are overgrown and invasive vegetation is 

present, needless risks to historic grave markers may 

also occur. 

Inappropriate maintenance activities can be devastating. 

One of the most common threats stems from improper 

lawn care, particularly the misuse of mowing equipment 

and string trimmers (weed whackers). The use of large 

mowers or mishandling them can lead to displacement 

of markers. Scrapes, gouges and even breakage also 

can occur. Improper use of string trimmers in areas 

immediately adjacent to grave markers can result in 

Figure 12. A cemetery professional undertakes a tree inventory in 

American Cemetery, Natchitoches, LA, to determine the health of 

trees in the cemetery. Management decisions for trimming or removal 

are based on the inventory. Photo: Debbie Dietrich Smith.
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scratching and even cutt ing into softer stone and wood. 

Generally, the use of chemical weed killers at the base of 

grave markers should be avoided, especially if there is a 

risk that the marker would absorb the chemicals.

Repointing masonry grave markers using Portland 

cement mortars that are harder than historic mortars 

often results in accelerated deterioration of the masonry 

material. Mortar should be softer than the adjacent 

masonry, enabling trapped moisture to migrate out, and 

serve as the sacrifi cial material when cracking occurs to 

relieve excessive stress. Problems also result when using 

impervious “protective” coatings that can trap moisture 

within the masonry, resulting in damage during wet/dry 

and freeze/thaw cycles (Fig. 13). 

Harsh cleaning products and techniques can have a 

detrimental eff ect on grave markers. Acidic cleaners such 

as muriatic acid can dissolve minerals in many masonry 

materials and can att ack metals. Alkaline cleaners, such 

as bleach, are notorious for leaving residual salts that are 

deposited on the surface (a process called effl orescence). 

Both acidic and alkaline cleaning can result in staining, 

especially if rinsing is inadequate. Using high-pressure 

water, above 500 to 1,000 psi, can needlessly damage 

materials as well, increasing their vulnerability to 

weathering (Fig. 14). If the marker is fragile, even low 

pressure water can be damaging. Techniques to avoid 

include aggregate blasting with sand or other harsh 

media and the use of power tools with abrasive wire or 

NyloxTM brushes. 

Pollution

Grave markers can be both visually and materially 

aff ected by pollution. Most readily apparent is the 

discoloration that takes place when airborne pollutants 

are deposited on markers. Depending on the exposure, 

how water is shed, and the marker material and 

intricacies, discoloration on markers will usually appear 

uneven and in streaks.

1. Maintain records on conditions and treatments 

of historic markers.

2. Seek advice from persons experienced with 

preserving historic markers when initiating a 

major maintenance or repair program.

3. Discourage visitor use of chalk, shaving cream, 

and other materials to highlight carvings and 

lett ering.

4. Train grounds crews in methods to avoid 

damage to historic markers, including fl at 

grave markers which can be easily damaged by 

machinery, fertilizers and weed killers.

5. Remove graffi ti as quickly as possible, using 

appropriate methods, so as not to encourage 

further marker disfi guration and vandalism.

6. Maintain ground cover around cemetery 

markers to avoid surrounding dirt from splashing 

back and staining grave markers.

7. Never use rotary grinders to resurface or 

“clean” historic markers.

8. Avoid the use of coatings on masonry without 

proper investigation.

9. Avoid high pressure water washing to clean 

historic markers.

10. Repair rather than replace damaged and 

deteriorated grave markers. For markers encased 

in cement, leave any repair work to trained 

conservators. 

Figure 13. The impervious 

coating used to “protect” 

this sandstone grave 

marker trapped moisture 

within the stone, 

eventually resulting in 

deterioration and surface 

loss. Photo: Fran Gale.

Figure 14. Highpressure water washing 

can damage grave 

markers. The photograph 

shows “wand marks” on 

the headstones produced 

by inappropriate 

pressure washing. 

Photo: Jason Church.

Avoiding 10 

Common Maintenance Mistakes
9

While the visual eff ect of pollution is often discoloration, 

less apparent is the potential damage caused by 

pollution to the grave marker materials themselves. 

Most rain is slightly acidic, and its pH (a measurement 

of acidity) becomes more acidic when pollutant gases, 

such as sulfur dioxide and nitrous oxides, are present. 

Acid rain damages materials containing calcium 

carbonate, such as limestone and marble, resulting in 

surface loss or erosion. When erosion is severe, the grave 

marker inscription, carvings and sculptural elements 

may become discernable. Recarving the inscription 

is not recommended. Instead, a small stand-alone 

interpretative sign could be placed nearby. 

Acid rain also damages bronze grave markers. Pollutant 

gases alter the composition of exposed bronze, often 

producing water-soluble minerals. These minerals are 

washed away during subsequent rains, resulting in 

surface erosion. If the bronze element is positioned 

on a masonry pedestal or plinth, the minerals are 

deposited on the masonry below. These eff ects of acid 

rain are disfi guring to the bronze element and associated 

masonry. 

Condition Assessments

Condition assessments help identify potential safety 

hazards, required preservation work, and any additional 

conservation that is needed for stabilization and 

protection of grave markers. Assessments also provide 

important baseline information about deterioration 

aff ecting grave markers. The collected information is 

helpful in determining and prioritizing maintenance 

tasks, identifying unstable conditions that pose an 

immediate threat, and for developing a plan for any 

needed repair or conservation work. Assessments 

should be recurring, preferably every spring. Condition 

assessments also help determine the extent and severity 

of damage following a disaster. 

Figure 15a. Condition surveys are undertaken to document current 

conditions, determine safety issues, and plan both emergency 

stabilization and future treatment plans. There are a variety of 

survey forms available that can be tailored to the specifi c cemetery. 

Photo: Mary Striegel.

Figure 15b. Photographs are used to document the condition of the grave 

marker as part of a condition assessment. Photo: Fran Gale.

Depending upon the size of the cemetery and funding 

available, the initial assessment may be carried out 

by a team consisting of cemetery staff , a materials 

conservator, and, where necessary, an architect or 

structural engineer for cases involving large monuments 

and mausoleums (Figs. 15a and 15b). For smaller 

cemeteries without large monuments and mausoleums, 

and where funding is problematic, volunteers can be 

trained to prepare a condition assessment under the 

guidance of an experienced individual. 

The fi rst step in any condition assessment is to gather 

background information, including cemetery records 

and documents, historical photographs, records of 

previous repair and maintenance work, and current 

practices. The next step is to conduct an on-site survey. 

Following the survey, recommended maintenance 

procedures should be provided. If the team or individual 

conducting the survey is experienced in repairing 

historic grave markers, their assessment should include 

information about appropriate materials and techniques 

for restoration and stabilization. 

Survey forms facilitate both recording of fi eld conditions 

and needed maintenance or repair work. Most forms 

include sections for marker type (headstone, obelisk, 

etc.), construction materials, orientation, dimensions, 

soil type, and grave marker deterioration. There 

are a number of excellent examples of survey forms 

available for download, including the National Park 

Service Condition Survey Form at www.ncptt .nps.gov 

However, because each cemetery is unique, it may be 

necessary to modify an existing form. 

A tool kit for the condition assessment may include 

binoculars, digital camera, magnifying glass, measuring 

tape, clipboard, carpenter’s rule, level, magnet, and 

fl ashlight. For large monuments, a ladder or aerial lift 

may be required. Photographs of each marker, including 

overall shots and close-up details, are an essential part 

of the documentation process. Photo logs are helpful for 
10

recording the date, direction, and photographer. Digital 

photographs should be captured in a standardized size 

and format (.tif, .jpg, .raw).

Defi ning conditions can be challenging, especially 

for cemetery staff and volunteers who are new to the 

process. There are a number of illustrated glossaries 

that can assist with determining accurate terminology 

for describing conditions. The ICOMOS Illustrated 

Glossary on Stone Deterioration Patt erns htt p://www.

international.icomos.org/ and the NACE International 

Resource Center Corrosion 101 htt p://nace.org/ are 

excellent resources.

 Where deterioration is apparent, the assessment should 

address questions such as: 

● What are the physical characteristics of the defects? 

Has deterioration obscured ornamental work or made 

the inscription diffi cult to read?

● What is the extent of the aff ected area? Are all areas 

of the marker aff ected by deterioration or is there a 

patt ern? 

● Do the conditions appear to be stable or gett ing 

worse.

● Are the defects aff ecting other materials or impacting 

the safety of visitors?

● Is deterioration contributing to loss or theft? 

● Is further investigation required?

Maintenance 

The old axiom that an ounce of prevention is worth 

a pound of cure certainly applies to the preservation 

of historic cemeteries. Maintenance is essential to the 

long-term preservation of historic grave markers. The 

principal components of a maintenance program include 

regular inspections, cyclical and prioritized maintenance 

work, and annual reports and budgeting. An important 

fi rst step is the development of a support team, 

including staff , conservators, engineers, skilled masons, 

and other professionals. In most cases, the cemetery 

manager should initiate this process.

The cemetery manager can use the information from the 

condition assessment report to develop a maintenance 

plan with a list of cyclical maintenance work. Many 

tasks can be carried out by in-house staff . For example, 

maintenance cleaning of metal and stonework can 

often be accomplished by rinsing with a garden hose. 

Applications of wax coatings can be used to protect 

bronze elements. Trained staff can undertake these 

tasks. Teaching graffi ti removal techniques to cemetery 

staff may also be necessary if vandalism is an on-going 

problem. Staff should have access to writt en procedures 

that include lists of appropriate materials and forms for 

recording the work completed. 

Some work is best done by specialists (Fig. 16). For 

example, unless there is a trained mason on staff , 

replacing deteriorated or missing mortar will require a 

skilled masonry contractor. Services of a conservator or 

trained cemetery specialist should be used for removing 

severe soiling and staining from grave markers and for 

carrying out adhesive repair work such as selectively 

replacing a piece of stone when a marker is damaged by 

mechanical equipment. Care should be taken to clearly 

defi ne the scope of work when hiring a contractor. 

It is useful to reference guidelines and preservation 

standards, such as those provided by the Secretary of 

the Interior or the American Institute for Conservation, 

whenever possible. 

Treatments

In historic cemeteries, preservation treatments are used 

to preserve grave markers and protect them from future 

deterioration. Tasks such as cleaning, where appropriate, 

painting, or lime washing may be undertaken both as 

an initial treatment and on a cyclical basis as part of the 

maintenance program for the site. Other treatments, 

including repointing, patching and fi lling, and resett ing, 

should be undertaken on an as-needed basis. 

It is important to note that the Secretary of the Interior’s 

Standards for Treatment of Historic Properties provide 

concepts and guidelines for maintaining, repairing, and 

replacing historic materials. The Standards promote 

best practices that will help to protect grave markers 

in historic cemeteries and other irreplaceable cultural 

resources. If replacement is required, the new material 

should match the old in composition, design, color, 

and texture. With chemical and physical treatments, 

the Standards recommend using the gentlest means 

possible.

Figure 16. A professional mason works to insert a new piece of stone. 

Often referred to as a “dutchman”, this repair technique requires 

replacing the deteriorated stone section with a new fi nished piece of 

the same size and material. Photo: Jason Church. 
11

Selecting A Conservator 

or Preservation Professional

A conservator or preservation professional can 

provide valuable assistance in preserving historic 

cemeteries by documenting and surveying 

cemetery conditions, assisting with work plans 

and prioritizing work, and recommending 

specifi c maintenance and repair procedures. More 

commonly, they recommend more specialized 

preservation treatments for historic markers and 

carry out the actual work. 

Specialized skills are required for undertaking 

certain treatments on historic grave markers 

or where markers are highly signifi cant or are 

in more advanced states of disrepair. When 

contracting for grave marker conservation, it 

is important to interview conservators who 

have worked in cemeteries. They should be 

experienced with the historic materials and 

nature of the conditions where the work is to 

be undertaken. Prior to selecting a conservator, 

details about their previous work and training 

should be obtained and confi rmed. Most 

conservators will provide sample reports and 

photographs of previous work. 

The American Institute for Conservation 

of Historic and Artistic Works (AIC) off ers 

information about selecting a conservator and 

what to expect once you have contracted with a 

conservator. Searching the “Find a Conservator” 

database provides a list of local and regional 

AIC members who have att ained Professional 

Associate or Fellow status in the organization. 

More information can be found on the AIC 

website at htt p://www.conservation-us.org/

A conservator will inspect grave markers before 

designing appropriate treatments and submit 

a writt en plan for their proposed conservation 

work that includes materials to be used, a cost 

estimate, and a schedule for the project. As part of 

the contract, the conservator should be required 

to submit a writt en completion report that clearly 

describes their treatment of the marker/s and 

includes maintenance and care recommendations.

Cleaning

Cleaning is carried out to remove soiling, staining, and 

contamination from grave markers (Fig. 17). Cleaning 

improves the visual appearance of the marker and 

sometimes reveals existing problems such as erosion 

and cracks. For various protective treatments, cleaning 

may be a necessary step in surface preparation. 

Although cleaning often is desirable and benefi cial, the 

use of improper materials and techniques can cause 

great damage; when cleaning historic grave markers 

is undertaken, one should keep in mind the principle, 

“fi rst do no harm.” 

To avoid a heavy build-up of soiling that might require 

aggressive cleaning procedures, regularly scheduled 

cleaning should be carried out by cemetery staff . The 

frequency of cleaning depends on a number of factors, 

including climate, location and vegetation. Before 

cleaning, an on-site inspection should be conducted 

to identify monument materials, including those not 

designated for cleaning since they may inadvertently 

come in contact with cleaning products and could 

be harmed. Temporary protective measure may be 

needed to safeguard nearby grave markers. Identifying 

the types of soiling present, including pollutants and 

contaminants, is important in deciding what cleaning 

procedures to use. 

For some monuments, existing conditions may preclude 

cleaning. Even gentle cleaning may not be recommended 

for conditions such as severe erosion, advanced 

deterioration, or fragile areas. Additionally, open joints, 

unstable repairs, and large cracks may require alternate 

cleaning procedures. 

General maintenance may involve low-pressure water 

washing. In most cases, surface soiling can be removed 

with a garden hose using municipal water or domestic 

Figure 17. Volunteers can undertake cleaning of grave markers once 

they have received initial training. Cleaning methods may include 

wett ing the stone, using a mild chemical cleaner, gently agitating the 

surface with a soft bristle brush, and thoroughly rinsing the marker 

with clean water. Photo: Jason Church.

water supply from a well. To avoid risks due to freezing, 

air temperature above 40° F is recommended for the time 

of treatment and subsequent 24 hours. To help remove 

stubborn soiling and dirt, soft, natural bristle scrub 

brushes are best. Avoid metal bristle brushes or fi rm 

nylon brushes and wrap metal elements with masking 

tape to avoid scratching grave markers. 
12

Soaking and/or spraying water in a fi ne mist are eff ective 

methods to remove natural growth. Water also has a 

“swelling action” for some soiling, making it easier to 

remove with gentle scrubbing. With cyclic spraying, a 

fi ne mist of water is directed at the targeted area for a 

short time (e.g., 20 minutes or less), followed by a short 

“off ” period. This on/off process is repeated several 

times. Because high-pressure water can abrade the 

surface, this treatment is not recommended for masonry 

monuments.

For stains that are not water soluble or where organic 

solvents are ineff ective, it is sometimes necessary to 

use chemical cleaning. Chemical cleaners include 

acids, alkalis, detergents and organic solvents. Each 

has advantages and disadvantages. Acids dissolve the 

interface between the stain and substrate while alkalis 

allow for longer dwell periods but must be neutralized. 

Some detergents are near-neutral in pH (neither acidic 

nor alkaline) and easier to rinse. 

Before selecting or using a chemical cleaning agent, the 

manufacturer’s Safety Data Sheet (SDS), available with 

the product and online, should be reviewed. The SDS 

provides information about the product’s composition, 

including identifi ed hazards, proper handling and 

storage, disposal, and required personal protective 

equipment. Once a chemical cleaning product has 

been selected, the manufacturer’s instructions should 

be followed. Before undertaking large-scale cleaning, 

it is always advisable to undertake small-scale tests 

(approximately 6" x 6"areas in discrete locations), and 

then waiting several days before assessing the results. 

Chemical cleaning is used to remove metallic stains and 

other contaminants such as old coatings and graffi ti. For 

severe staining, poultice cleaning is useful as it extends 

contact time with the cleaner. A poultice is a mixture of 

clay or other inert material, such as paper pulp, and a 

cleaning agent. The mixture is applied to the surface and 

allowed an extended dwell period. The chemical cleaner 

dissolves the stain and the clay draws the stain out to the 

surface. When using a poultice, it should be applied just 

beyond the stained area and covered with polyethylene. 

The best practice is to leave the treatment on the surface 

for 24 hours and then remove the polyethylene cover 

and allow the poultice to continue drying. Once the 

poultice is dry, the mixture is then collected and the 

surface is thoroughly rinsed. For some stubborn stains, 

the application may need to be repeated. 

Chemical cleaning also may be required if biological 

growth (algae, fungi and lichen) is severe. A study 

conducted by the National Park Service provides 

guidelines for cleaning government-issued marble 

headstones and recommends biocidal cleaners that 

contain quaternary ammonium compounds. Like all 

cleaning methods, chemical cleaning can accelerate 

deterioration. Adverse eff ects include effl orescence, 

stains, and etching. 

Graffi ti Removal 

Markers with graffi ti tend to be targets for further 

vandalism (Fig. 18). Timely removal helps deter future 

vandalism and improves the marker’s appearance. 

If the graffi ti is water soluble, it can be removed using 

water and a soft cloth or towel. Rinsing the cloth 

frequently helps to avoid smearing graffi ti on unaff ected 

areas. If the graffi ti is not water soluble, organic solvents 

or commercial graffi ti removal products suitable for 

the grave marker material are recommended. Products 

should be tested prior to use. General cleaning of the 

entire marker is a good follow-up for a more even 

appearance. For deep-seated graffi ti, poultice cleaning 

(previously described) may be required to extract 

staining materials. 

Repointing 

Missing and deteriorated mortar in old cemetery 

grave markers is a common condition, and the mortar 

should be replaced to prevent water intrusion and 

potential damage (Fig. 19). Several questions should 

be considered when selecting materials for repointing. 

Figure 18. Graffi ti is carefully removed using a low-pressure dry-ice 

misting instrument. Photo: Jason Church.
13

Most importantly, what is the masonry substrate that 

requires repointing? What mortar mix is suitable for 

the historic masonry? How quickly will mortar need 

to cure? Soft mortars contain traditional lime putt y or 

modern hydrated lime. Harder mortars contain natural 

or Portland cement. If necessary, mortars can be tinted 

with alkali-stable pigments to match historic mortar 

colors. The selection of the mortar to be used is critically 

important to the success of the project. An inappropriate 

mortar can result in unatt ractive work and accelerate 

the deterioration of the historic grave marker. Always 

avoid the use of bathtub caulk and silicone sealants for 

repointing mortar joints. 

Prior to repointing, any loose and deteriorated mortar 

needs to be removed from the joint, preferably using 

hand tools. Following joint preparation, the mortar 

materials (lime, cement, and sand) are mixed, and then 

water added to form a stiff paste. The repointing mortar 

is applied using a tuck pointing trowel, typically with a 

narrow 1/8"- 1/2" fl at blade. Mortar is compacted into the 

joint, and then excess mortar is removed and the original 

joint profi le replicated. Good repointing requires skill. 

Generally, a mason or person with masonry training 

should repoint mortar joints. 

Resett ing

Resett ing is recommended for grave markers when their 

foundations are unstable or out of plumb (Figs. 20a 

through 20c). This often complex activity involves lifting 

the grave marker, leveling its foundation, and returning 

the marker to its original upright position. Workers can 

be injured and the grave marker damaged if resett ing is 

not carried out properly and safely. 

Inexperienced staff or volunteers should not att empt 

resett ing without training from a conservator, engineer, 

or other preservation professional. When dealing with 

fragile or signifi cant grave markers, or those with large 

Figure 19. Masonry markers like this box tomb may require the 

repointing of mortar joints. It is important to use a mortar that is 

softer than the historic brick. In this case a conservator uses a lime 

putt y-based mortar to repoint. Photo: Jason Church.

Figure 20a. This slate grave marker in the Ancient Burying 

Ground in Hartford, CT, is a ground-support stone. Resett ing 

requires digging a hole that will hold the base of the stone and 

then compacting the soil at the bott om of the hole by hand. 

Photo: Fran Gale.

Figure 20b. To facilitate drainage, crushed stone, gravel, and sharp 

sand line the hole and are hand-tamped around the stone after 

placement. Photo: Fran Gale.

Figure 20c. The reset ground-supported grave marker should be level 

and plumb. Photo: Fran Gale.
14

Safety

Encouraging the public to visit and explore public 

burial grounds and cemeteries increases awareness 

of the value of these sacred sites. If visitation is 

promoted, owners and property managers must 

be responsible for ensuring that their sites are safe 

for staff and visitors. This responsibility includes 

monitoring the condition of grave markers. 

Historic cemeteries can be hazardous workplaces 

for staff members, consultants, contractors, and 

volunteers. Awareness of potential hazards in a 

historic cemetery and careful planning are essential 

to avoiding injury. Maintain an appropriate fi rst aid 

kit on site for minor injuries and have an emergency 

plan in place that includes contact information for 

medical assistance. 

Creating a safe work environment in historic 

cemeteries requires appropriate planning for each 

project, starting with personal protective equipment. 

Suitable clothing and personal protective equipment 

should be fundamental safety requirements. 

Supportive shoes such as steel toe work boots or 

sturdy lace-up shoes help protect ankles and feet 

from injury, just as good work gloves help protect 

hands from cuts, scrapes, and splinters. Whether 

using a chipper, drill and other power tools or 

equipment, safety glasses or goggles are essential. 

A back brace often is recommended for heavier 

lifting tasks. Do not work alone or, if you must, tell 

someone where you are and when you expect to 

return. 

During hot weather, heat stress is a present risk. 

Besides knowing the signs of heat stress, preventive 

measures should be taken by each worker: 

● Wear light, loose-fitt ing, breathable clothing and a 

broad-brimmed hat.

● Use sunscreen, reapplying as needed.

● Take frequent breaks in the shade.

● Make sure fresh water is available and drink to 

stay hydrated. 

● Eat small meals before and during work. 

● Avoid caff eine, alcohol, and large amounts of 

sugar.

Trip and falling hazards include uneven ground, 

holes, open graves, toppled grave markers, fallen 

tree limbs, and other debris (Fig. C). Sitt ing, 

climbing, or standing on a grave marker should 

be avoided since the additional weight may cause 

deteriorated and structurally unstable monuments 

to break or collapse with serious injury potentially 

occurring to the worker and damage to the marker. 

To help prevent injuries that can result from 

unstable grave markers, it is important to routinely 

identify and fl ag severely damaged and unstable 

grave markers for corrective work and to rope off 

any marker considered to be in immediate danger 

of collapse. Prior to beginning work, the immediate 

area around the job site should be rechecked for 

safety hazards.

Snakes, wasps, and burrowing animals inhabit 

historic cemeteries (Fig. D). Snakes sun on 

warm stones and hide in holes and ledges, 

so it is important to be able to identify local 

venomous snakes. An appropriate venomous 

snake management plan should be in place, and 

Figure C. Gophers and other burrowing animals produce uneven 

ground and holes that are trip and falling hazards to visitors and 

staff of historic cemeteries. Photo: Jason Church.

Figure D. Yellow jackets that are nesting below the projecting 

molding of this grave marker pose a hazard to visitors and 

staff because, if disturbed, they will vigorously defend their 

nest. Yellow jacket, paper wasp and hornet nests should be 

removed from grave markers by trained staff or specialists. 

Photo: Jason Church.
15

all workers should be familiar with it. Workers 

and volunteers should be instructed as to safety 

measures to be taken in regards to snakes, including 

proper clothing where there is an identifi ed risk. 

The imported red fi re ant is an invasive pest, 

prevalent in the southern United States. They att ack 

en masse, resulting in painful bites that can be 

potentially life threatening to people with allergic 

reactions. It is important to be able to identify the 

presence of red imported fi re ants; be informed as 

to safety measures to take when working in areas 

known to be infested with them; and take steps to 

control them as necessary. A rescue medicine is 

available for those with serious allergic reactions.

Paper wasps, yellow jackets, and hornets are another 

concern, building nests around and on ledges and 

lips of box tombs, mausoleums, and other grave 

markers. They are very territorial around their nests 

and will vigorously defend them. There are nontoxic sprays that can be used in and around the work 

area. Nests should be safely removed. 

Burrowing animals like armadillos, groundhogs, 

gophers, and moles disrupt the ground with their 

digging and tunnels and can create tripping hazards 

or undermine grave markers. Prairie dogs have 

been known to dig up bones and destroy gravesites. 

Sinkholes created by these animals can also be 

perfect places for other creatures like snakes to 

inhabit.

Proper work practices and lifting techniques need to 

be used whenever lifting or resett ing grave markers. 

Many markers are surprisingly heavy. For example, 

a common upright marble headstone measuring 

42" long, 13" wide, and 4" deep weighs over 200 

pounds. Volunteers and workers should work in 

pairs, be able bodied, and have training in safe 

Figure E1. The simple wooden clamp system allows two people 

to safety lift a marble grave marker. Photo: Sarah Jackson.

Figure E2. The clamp system is constructed from off -the-shelf 

wooden boards. Photo: Sarah Jackson.

lifting techniques. Lift equipment and ergonomically 

correct tools should be routinely used to lift heavy 

markers (for most people this includes markers that 

weight more than 50 pounds). For smaller grave 

markers, a simple wooden clamp system can be 

constructed for a two-person lift (Figs. E1 and E2). 

stacked bases, a specialist should be contracted for 

resett ing. 

It is important to check state and local regulations to 

make sure that digging around the grave marker is 

authorized before starting any resett ing eff ort. Also, 

grave markers should be documented and cleaned 

before resett ing. It is also a good time to measure and 

record the overall size of the marker and note any stone 

carver’s marks or inscription of the company that made 

the marker. The company name is often found on buried 

portions of the base and revealed during the resett ing 

process. 

Typical materials required for resett ing include a hoist, 

shovels, plumb lines, levels, tamping devices, wooden 

stakes, and boards. To improve drainage, sand and 

small gravel or small stones are commonly used when 

resett ing. 

Prior to resett ing, it is important to establish the type 

of base. Most grave markers have one of three main 

base types: (1) ground supported, (2) slott ed base, or (3) 

stacked base. Similar tasks are undertaken for each base 

type. 

Ground-supported stones are a common type of historic 

grave marker. This type includes the traditional New 

England slate and brownstone markers and governmentissued marble headstones. The primary goal with any 

ground-supported marker is to have it level and plumb. 

To reset the marker, a few inches or more of soil is 
16

fi rst removed from around the stone. This is usually 

suffi cient to enable a stone marker to be straightened. 

The enlarged hole is then fi lled and compacted around 

the marker.

If a grave marker has fallen over and has been covered 

with soil or turf, it must fi rst be inspected for att ached 

concrete or other anchoring system. If this system is still 

att ached, the grave marker may break during lifting. 

After removing the stone, it can be cleaned and then 

temporarily set on wood supports. 

The hole left from removal of the marker will need to 

be enlarged to hold the base of the stone. Soil at the 

bott om of the hole should be compacted by hand, not 

with a power tamper. In most cemeteries, crushed stone 

or sharp pea-size gravel mixed with angular sand can 

be used to line the hole and then hand-tamped around 

the stone after it is placed in the hole. The gravel helps 

facilitate drainage and keeps the stone from sett ling. 

A bubble level can be used to ensure that the stone is 

plumb. Markers should not be set in concrete. 

 The second type of monument base is the slott ed base 

where the upright element is secured to the base using 

mortise-and-tenon style construction. The upright 

element in the slott ed base may be leaning or loose. In 

any case, the upright element should be removed from 

the base, the base leveled, then the element returned to 

the base. It is important to keep in mind the depth that 

the base was intended to be set into the ground. This 

may be indicated by the style of the base or the observed 

soil- line staining. Many bases were intended to sit 

fl ush on grade while some were set a few inches below 

ground. 

Prior to resett ing, the upright element should be 

disengaged from the base and carefully set aside. In 

most cases, the base will need to be removed to properly 

prepare the hole before resett ing the grave marker. After 

doing so, four to six inches of soil should be removed 

from the hole and the soil then tamped by hand to make 

a proper bed or foundation. The foundation area can be 

fi lled with crushed stone or sharp pea-sized gravel and 

sand, checking to make sure that the base is plumb and 

level as resett ing proceeds. Clean the headstone prior 

to resett ing. Old mortar, concrete or epoxy should be 

removed from the slot and the bott om of the upright 

element using a hammer and small chisel. Once the 

stone elements are cleaned and the base is level and 

plumb, the next step is placing the upright element into 

the slot. A lime mortar can be used to fi ll any gaps in 

the slot. This prevents water intrusion that may cause 

marker movement related to freeze-thaw cycles. 

A third common base type is the stacked base. This 

style includes at least one element placed on a base or a 

series of bases of varying sizes. Resett ing a stacked-base 

grave marker usually requires special skills and lifting 

equipment. Depending upon the complexity of the 

marker, a conservator, experienced masonry contractor, 

or preservation professional with engineering skills is 

usually needed. 

The sections of a stacked-base grave marker often are 

pinned together for support. If deteriorated, the pins 

should be replaced. Using a hammer and chisel, a 

conservator or person experienced in working with 

historic grave markers should remove any corroded 

iron, copper, or bronze pins, as well as the old mortar 

or adhesive adhered to each section. Replacement 

pins should be stainless steel all-thread, and sized 

slightly shorter and smaller than the existing hole. 

The replacement pins then can be set with epoxy, lime 

mortar, or packed in lead. Once the pins are in place, 

the sections of the stacked base can be individually 

reset using traditional or contemporary materials. These 

include lead, shims, mortars, and sett ing compounds. 

Finally, each gap or seam between sections should be 

pointed with a sett ing compound or appropriate mortar 

to prevent water intrusion.

Filling and Patching 

Hairline masonry cracks may be the result of natural 

weathering and require no immediate treatment except 

to be photographed and recorded. However, larger 

cracks often merit further att ention. Repairing masonry 

cracks involves several steps and typically a skilled 

hand (Fig. 21). The repair begins with the removal of 

loose material and cleaning. Materials that are used for 

crack repair include grouts for small cracks and epoxy 

for large cracks aff ecting the structural integrity of the 

monument. Gravity or pressure injection is used to 

apply grout or epoxy. Crack repair can be messy, so 

careful planning and experience are helpful. If the crack 

is active, a change in size of the crack will be noted 

over time. Active cracks require further investigation to 

ascertain the cause of the changes, such as diff erential 

sett lement, and to correct, if possible, the cause prior to 

repairing the crack. 

Figure 21. Cracks in a stone marker should be fi lled to keep water and 

debris out and prevent the crack from becoming larger. A patching 

mortar is designed to be used, in this case, with historic marble. 

Photo: Mary Striegel.
17

Repairing masonry markers with severely damaged or 

missing pieces requires a skilled mason or conservator. 

The materials used for patching are similar to those 

used for repointing mortar joints. With patching, it is 

critical that the physical and mechanical properties of 

the patching material be appropriate for the masonry 

material. Work includes designing a durable patch 

compatible with the substrate. Proper curing is 

especially critical for large patches and often involves 

procedures to protect the patch from premature drying. 

Repairs to stucco-covered surface should be carried 

out by a skilled plasterer using a stucco mix that is 

compatible with the original material.

Repairing delaminated slate and brownstone grave 

markers also requires a skilled mason or conservator. 

With this condition, there are openings along bedding 

planes which expose the stone grave marker to moisture 

intrusion. Treatments are design to eliminate or reduce 

moisture intrusion that would accelerate deterioration. 

The selection of appropriate repair materials and 

procedures depends on the severity of the condition. 

Traditionally, delaminated slate or brownstone grave 

markers were “capped” with a strip of lead or other 

metal. Today, this repair technique is seldom used, in 

part because the drilling procedure used to att ach the 

cap can be damaging, if the stone is britt le. Also, there 

are toxicity issues associated with the use of lead. An 

alternative approach is to fi ll the openings exposed 

by delamination with grout or patching material that 

is compatible with the stone. Adhesion of the repair 

material to the delaminated surfaces is particularly 

important. 

The decision whether to use patching material 

or undertake a dutchman repair with matching 

materialdepends on the grave marker material, 

location of the damaged area, size, and other factors. 

A successfully executed dutchman usually results in a 

repair that has long durability and maintains a similar 

weathering patt ern to the adjacent historic material. 

When working with stone grave markers, repairs using 

dutchman techniques are best done by a skilled stone 

craftsman. 

Detached fragments should be collected, documented 

and stored in a suitable facility. Reatt achment of these 

fragments should be undertaken by a conservator or 

mason. This work often requires pins to reinforce the 

joints and patching to compensate for losses. 

Protective treatments 

Protective treatments for metal, stone, and wood grave 

markers stabilize corrosion and protect the monument 

from rainwater, pollutants, and other contaminants. 

Treatments may vary not only due to material 

diff erences, but also to specifi c site conditions.

Wax coatings are often used for bronze markers (Fig. 

22). Wax provides a protective barrier against moisture, 

soiling, and graffi ti. There are several steps in the wax 

application process. Where there is litt le corrosion, 

gentle cleaning of the marker is undertaken prior to 

applying the wax coating. Apply a thin layer of wax 

to the marker using a stencil brush or chip brush. 

Mineral spirits can be added to the wax to facilitate 

Figure 22. A protective coating must be maintained on metal 

elements. Wax or lacquer coatings help preserve the bronze patina 

and slow corrosion. Conservators apply a microcrystalline wax to this 

bust at St. Mark's Church in-the-Bowery, New York, NY. 

Photo: John Scott .

brush application. A soft, clean cloth is used to remove 

excess wax and buff the surface. A second coat of wax is 

sometimes needed. 

In most climates, iron objects require coatings to protect 

them from corrosion. Clear coatings are sometimes 

used to protect wrought iron objects. A corrosion 

inhibitive primer and topcoat are used for cast iron and 

steel objects. Direct-to-Metal (DTM) coatings combine 

the two. Because of their durability, acrylic enamels, 

urethane, and fl uoropolymer coatings are preferred. 

Proper surface preparation is important, including 

the removal of surface soiling, fl aking paint, and 

loose rust. This can be accomplished with compressed 

air, wire brushing, solvent rinsing, or other cleaning 

method. Next the surface is cleaned with a damp 

cloth, repeatedly rinsing the cloth as needed. While the 

surface needs to be thoroughly dried before painting, 

it is important to repaint as soon as possible since even 

overnight condensation deposits are not desirable. 
18

Another approach for iron objects is using a rust 

converter to stabilize corrosion that involves less surface 

preparation. Commercially available rust converters 

contain tannin or phosphoric acid and react with rust 

to form more stable iron compounds. The surface must 

be painted following surface preparation with the rust 

converter. 

Limewash is a traditional coating that brightens stuccocovered grave markers (Fig. 23). Like paint coatings, it 

needs to be periodically applied. Limewash is prepared 

with lime putt y or hydrated lime and water. Curing 

begins following application. The lime putt y or hydrated 

lime reacts with carbon dioxide in the air in a process 

called carbonation. This reaction eventually forms 

calcium carbonate, a stable hard coating. Limewash is 

a “green” coating with no volatile organic compound 

content and is “breathable,” i.e., it allows for water vapor 

transmission. Although commonly white, limewash can 

be colored or tinted with alkali-stable pigments such as 

iron oxide. 

Before applying the limewash, the masonry surfaces 

should be inspected for coating residues that need to 

be removed and any required repair work undertaken. 

Stucco-covered surfaces should be repaired and allowed 

to fully cure before applying limewash. If the original 

color has been determined, the renewal coating can be 

formulated to match. In preparing the wash, enough 

water is added to lime putt y or hydrated lime to produce 

slurry with the consistency of skim milk. A mixture of 

four parts water and one part lime usually works well. 

A Zahn or Ford cup can be found at a hardware store 

and used to measure the thickness of the limewash and 

ensure consistency with each batch. Although many 

traditional recipes include additives, a simple mixture 

of lime and water performs best. Using a power drill 

with a paddle att achment to stir the limewash will help 

ensure that the lime particles are fully suspended in the 

Figure 23. Limewash is a breathable coating sometimes used to 

protect the surface of the grave marker and provide a decorative 

fi nish. Limewash is applied by brush in fi ve to eight thin coats (with 

each coat about the consistency of skim milk). The surface is allowed 

to slowly dry between coats. Sometimes the surface is covered by 

damp burlap to slow the drying process. Photo: Sarah Jackson.

mixture. Any pigment for coloration is added during the 

fi nal mixing. 

The surface must be cleaned of old coating residues, 

soiling, and other contaminants. After dampening 

the surface, the limewash is applied in 5-8 thin coats, 

allowing each coat to dry between applications. 

Limewash is translucent immediately after application 

and then becomes opaque when dry. 

Proper curing of limewash is critical to its durability. To 

prevent premature drying, the treated surface may need 

to be covered with damp burlap. Limewash must not be 

applied when frost or freeze conditions are predicted or 

in temperatures above 90° F. Ideally, limewash should 

be applied during spring or fall when temperatures are 

around 70° F, avoiding direct sunlight where possible. 

Clear water repellents and consolidation treatments 

are sometimes considered for severely deteriorated 

grave markers, including unpainted wood markers and 

masonry. For wood markers, epoxy consolidants are 

used to patch and repair. For masonry materials, it is 

important to remember that they are porous, and water 

vapor and liquid water can travel through their internal 

network. Protective treatments must allow for water 

vapor transmission to prevent trapping moisture inside 

the marker. Although a wide variety of water repellents 

have been employed on masonry (wax, acrylic, epoxy 

resins, etc.), silane and siloxane treatments have been 

the most successful. These organosilicon compounds 

are “breathable,” penetrate below the surface, and form 

chemical bonds with silicate minerals.

When erosion is severe, consolidation treatments (e.g., 

ethyl silicate) have been used to replace mineral binders 

lost to weathering (Fig. 24). Because these treatments 

are not reversible, laboratory and on-site testing 

are essential. Application by a conservator or other 

experienced preservation professional is advised. 

Figure 24. A severely deteriorating monument or grave marker can 

be treated with a stone consolidant. The treatment is usually applied 

using a spray system. The consolidant soaks into the stone and 

replaces mineral binders that hold the stone together. On-site and 

laboratory testing and evaluation are performed prior to using this 

non-reversible type of treatment. Photo: Lucas Flickinger.
19

Conclusion

Maintenance is the key to extending the life of historic 

cemetery grave markers. From ensuring that markers 

are not damaged by mowing equipment and excessive 

lawn watering, to proper cleaning and resett ing, good 

cemetery maintenance is the key to extending the life of 

grave markers. Whether rescuing a long-neglected small 

cemetery using volunteers or operating a large active 

cemetery with paid staff , the cemetery’s documentation, 

maintenance and treatment plans should include 

periodic inspections. Only appropriate repair materials 

and techniques that do not damage historic markers 

should be used and records should be kept on specifi c 

repair materials used on individual grave markers. A 

well-maintained cemetery provides an att ractive sett ing 

that can be appreciated by visitors, serves as a deterrent 

to vandalism, and provides a respectful place for the 

dead. A community history recorded in stone, wood and 

metal markers, cemeteries are an important part of our 

heritage, and are deserving of preservation eff orts (Fig. 

25). 

Figure 25. Involving the community in activities helps to develop an 

appreciation for the cemetery and serves to deter vandalism. Events 

may include children through school or scouting organizations and 

can help teach across the curriculum. Photo: Debbie Dietrich Smith.

Additional Reading

Stragstad, Lynett e. A Graveyard Preservation Primer. 

Altamira Press; Second Edition (August 28, 2013)

Jackson, Sarah Marie, Tye Bott ing and Mary Striegel, 

“Durability of Traditional and Modifi ed Limewashes,” APT 

Bulletin, Vol. 38, No. 2/3, 2007.

Matero, Frank G. and Judy Peters. “Survey Methodology for 

the Preservation of Historic Burial Grounds and Cemeteries.” 

In APT Bulletin, Vol. 34, No. 2/3 (2003), pp. 37-45.

Grissom, Carol A. and Ronald S. Harvey. “The Conservation 

of American War Memorials Made of Zinc.” In Journal of 

the American Institute for Conservation. Vol. 42, No. 1, 

Architecture Issue (Spring, 2003), pp. 21-38 

National Park Service publications, NCPTT:

Best Practice Recommendations for Cleaning GovernmentIssued Headstones. Mary F. Striegel, 2011. 

Wooden Artifacts in Cemeteries: A Reference Manual. Ronald 

W. Anthony and Kimberly Dugan. 2007

Identifi cation of Unmarked Graves. Rinita A. Dalan, Steven L. 

DeVore and Earl Clay. 2008

National Park Service publications, Technical 

Preservation Services:

A Glossary of Historic Masonry Deterioration Problems and 

Preservation Treatments. Anne E. Grimmer. 1984, reprinted.

Keeping It Clean. Anne E. Grimmer. 1988. 

Preservation Brief 1: Cleaning and Water-Repellent 

Treatments for Historic Masonry Buildings. Robert C. Mack, 

FAIA, and Anne E. Grimmer. 2000.

Preservation Brief 2: Repointing Mortar Joints in Historic 

Masonry Buildings. Robert C. Mack, FAIA, and John P. 

Speweik. 1998.

Preservation Brief 15: Preservation of Historic Concrete. Paul 

Gaudett e and Deborah Slaton. 2007.

Preservation Brief 22: The Preservation and Repair of Historic 

Stucco. Anne Grimmer. 1990.

Preservation Brief 38: Removing Graffi ti from Historic 

Masonry. Martin E. Weaver. 1995.

Preservation Brief 42: The Maintenance, Repair and 

Replacement of Historic Cast Stone. Richard Pieper. 2001.

Preservation Tech Note 1: Conserving Outdoor Bronze 

Sculpture. Dennis Montagna. 1989.

National Park Service , National Register Bulletins:

Guidelines for Evaluating and Registering Cemeteries and 

Burial Places. Elisabeth Walton Pott er and Beth M. Boland. 

1992.

National Park Service publications, Museum 

Management Program: 

Conserve O Gram, 10/4 Caring for Outdoor Bronze Plaques, 

Part I: Documentation and Inspection. 2005

Conserve O Gram, 10/5 Caring for Outdoor Bronze Plaques, 

Part II: Cleaning and Waxing. 2005. 
20

About the Authors

Dr. Mary Striegel directs the Material Conservation 

Program at the National Park Service’s National Center 

for Technology and Training (NCPTT) in Natchitoches, 

Louisiana. Frances Gale is the former Training Chief 

(NCPTT) and currently is a Senior Lecturer and Director 

of the Architectural Conservation Laboratory, University 

of Texas at Austin. Jason Church is a Materials 

Conservator with NCPTT. Debbie Dietrich-Smith is the 

Chief, Historic Landscape Program, NCPTT.

Acknowledgements

The authors wish to thank Francis Miller, Conservator, 

ConserArt LLC; Mark Wolfe, Executive Director and 

Jennifer McWilliams, Cemetery Preservation Program 

Coordinator, Texas Historical Commission; Gus Fraser, 

Vice President of Preservation and Facilities, Mount 

Auburn Cemetery; Sara Amy Leach, Senior Historian 

and Jennifer Perunko, Historian, National Cemetery 

Administration, Department of Veterans Aff airs; and 

Jenny Parker Technical Preservation Services, National 

Park Service for their insightful comments in reviewing 

the brief. Thanks also go to Kirk Cordell, Executive 

Director, NCPTT, and Brian Goeken, Chief, Technical 

Preservation Services. Charles Fisher, Technical 

Preservation Services provided invaluable assistance in 

the editing and preparation of this brief. 

This publication has been prepared pursuant to the 

National Historic Preservation Act, as amended, 

which directs the Secretary of the Interior to develop 

and make available information concerning historic 

Whether large or small, well maintained or neglected, historic 

cemeteries are an important part of our cultural landscape. This 

historic cemetery at Cape Lookout National Seashore, NC, provides 

a record of the families who lived in Portsmouth Village during the 

19th and early 20th centuries. Photo: Fran Gale.

properties. Additional information off ered by Technical 

Preservation Services is available on our website at 

www.nps.gov/tps. Further information on the programs 

and resources of the National Center for Preservation 

Technology and Training can be found at www.ncptt .

nps.gov. Comments about this publication should be 

made to: Technical Preservation Services, National Park 

Service, 1849 C Street NW, Washington, DC 20240. 

This publication is not copyrighted and can be 

reproduced without penalty. Normal procedures for 

credit to the authors and the National Park Service are 

appreciated. Excepting for the photographs by the 

authors, the photographs used in this publication may 

not be used to illustrate other print or electronic media 

without permission of the owners. Photographs by the 

authors should be credited with author’s name, NCPTT. 

September 2016