A stone's throw: Asheville's legacy of Pebbledash & Roughcast

              The Historic
Dimension Series
A student publication series by the UNCG Department of Interior Architecture
A Stone’s Throw:
Asheville’s Legacy of Pebbledash & Roughcast
by Sunny Townes Stewart 		 Spring 2013
While the Appalachian
Mountains may
be known for their quintessential log
cabins, the dominant architectural style
of Asheville, North Carolina—located in
the southwestern corner of the state near
the Tennessee border—does not fit the
traditional stereotype. Instead, the hilly
streets of the city’s suburbs are dotted with
quaint, picturesque homes reminiscent of
English cottages, clad in false half-timbering,
wooden shake siding, exposed stone, and
a coarse stucco that many in Asheville call
pebbledash (though most examples in the
city are more accurately a related rendering
style called roughcast).
Introduced to the region by English
architect Richard Sharp Smith (1852-1924),
pebbledash is abundant in neighborhoods
that were built at the turn of the twentieth
century, such as Biltmore Village (see
Figs. 6 and 7) and Montford (see Figs. 8
and 9). Smith is regarded as Asheville’s
most influential architect during the late
nineteenth and early twentieth centuries—a
period marked by rapid population growth
and construction—and other designers and
builders quickly adopted his distinctive
styles. By the 1930s, the “earthy, richly
textured pebbledash” had become a defining
characteristic of Asheville’s residential
districts (Asheville-Buncombe HRC).
History of Pebbledash
Pebbledash and roughcast are heavily
textured and durable forms of stucco, a
plastering technique used by builders in
ancient Egypt, Greece, and Rome (Millar,
2). While most interior and artistic plaster
is smoothed flat, stucco—often used
for outdoor surfaces—includes a sandy
substance to provide a “sugary texture” (see
Fig. 3). Pebbledash and roughcast (see Figs.
4 and 5) feature a more prominent aggregate
like gravel or pebbles, glass, shells, broken
pottery, or mineral shards, depending on
what was locally available in the region
(Taylor).
The technique was common in England,
particularly in coastal regions and other
areas with harsh weather. According to
Anne Grimmer, author of the National Park
Service (NPS) Preservation Brief on historic
stucco, render of all types was a weather-repellent
coating that offered a layer of
insulation and protected the building from
wind and rain penetration, as well as fire.
As such, stucco as an architectural feature
“probably has a history as old as lime
mortar itself” (Taylor).
Roughcast render was often used during the
Middle Ages to cover the panels between
buildings’ timber framing (see Fig. 2). In his
1897 treatise Plastering: Plain and Decorative,
craftsman William Millar noted that
roughcast was “one of the oldest forms of
external plastering” because of its durability
(210). Though it was often shunned during
the Victorian era, the roughcasting tradition
was renewed with the cottage ornée (or
decorated cottage), Tudor revival, and Arts
and Crafts movements of the nineteenth
century (Taylor). According to architectural
“Roughcast, as
conservationists
prefer to call the
earliest material,
probably has a
history as old as
lime mortar itself.”
-Jonathan Taylor,
conservator
“Plastering is one
of the earliest
instances of man’s
power of inductive
reasoning, for
when men built
they plastered: at
first, like the birds
and the beavers,
with mud, but
they soon found
a more lasting
and comfortable
method, and the
earliest efforts
of civilisation
were directed to
plastering.”
-William Millar,
nineteenth-century
craftsman
UNCG The Historic Dimension Series: 2
Fig. 2: A seventeenth-century cottage featuring half-timbering
and roughcast render in Hampshire, England.
conservator Jonathan Taylor, however, it was Richard
Norman Shaw’s popular Queen Anne style that was
likely most responsible for roughcasting’s popularity.
Its “asymmetric composition of steeply pitched roofs,
jettied floors, small-paned windows and rough textures
evoke an atmosphere of cosy cottage comforts with
roaring log fires” (Taylor). All of these late nineteenth
and early twentieth century styles tend to combine
a variety of textures, including brick, tile, wooden
shingles, exposed wood timbers, native stone, and
roughcast renders.
It is obvious that Richard Sharp Smith was influenced
by the popularity of these styles before immigrating
to the United States, as he often mixed their motifs
into his designs (see Figs. 6-9). He moved to Asheville
in 1888 (from England via New York) to supervise
the construction of Biltmore, George Washington
Vanderbilt’s sprawling French chateau retreat that was
designed by Smith’s employer, Richard Morris Hunt.
After its completion, Vanderbilt commissioned Hunt
and Smith to design a village that would support the
operation of the mansion.
Embracing its role as a manorial village, of sorts, the
architects utilized designs reminiscent of medieval
England. They blended arts and crafts, Tudor revival,
and cottage ornée styles featuring steeply pitched,
gambrel roofs; false half-timbering; decorative
bracketing; and roughcast siding (see Figs. 6 and 7).
After Hunt’s death, Smith settled permanently in the
mountains, continuing to utilize similar motifs in the
hundreds of homes that he designed throughout the late
nineteenth and early twentieth centuries. The rough,
rustic nature of the technique of roughcasting and or
pebbledash complemented the natural surroundings and
the other decorative elements. By the turn of the century,
the technique had been adopted by other architects in
the region, entering into the “building vocabulary” of
Asheville (Bishir et al., 429).
Techniques for Mixing and Application
The techniques for pebbledash and roughcast renders
are very similar, and in fact during the Arts and Crafts
era were often used interchangeably, though there
were regional variations (for example, Millar notes that
harling was the term of choice in Scotland). Like other
forms of plaster, both require multiple coats. When the
pebbledash is used to cover textured masonry like brick,
stone, or concrete block, the first layer is applied directly
to the wall. In other instances, like when it is being used
to cover log construction or smooth panels, lath—either
small wood slats or, especially in the late-nineteenth and
early-twentieth centuries, metal meshing (see Fig. 11)—
is necessary to encourage the render to form a strong
bond, or key (Grimmer).
Millar called the makeup of the first layer coarse-stuff
because it included sand and horse or ox hair to
encourage the plaster to form a stronger key. Before it
dried, the craftsman usually scratched the surface in
order to encourage the second coat to key (Millar, 210).
During the application, it is necessary to keep the surface
being covered—be it wood lath, masonry, or a layer of
cured render—damp to “ensure a good bond ... [and]
prevent them from pulling moisture out of the stucco
too rapidly, which results in cracking, loss of bond, and
generally poor quality stuccowork” (Grimmer, 7).
The difference between the application of stucco,
roughcast, and pebbledash comes with the next step.
With regular stucco, a more refined mixture would
be used to form the third and final, skillfully textured
layer (Fig. 3). For traditional roughcast or pebbledash
applications, however, the aggregate was thrown
forcefully onto the still-soft second coat of stucco, as
the names (pebbledash and roughcast suggest). Millar
instructed that the material to be dashed should be no
Fig. 3:
Traditional stucco
Fig. 5:
Roughcast
Fig. 4:
Pebbledash
UNCG The Historic Dimension Series: 3
more than ¼- and ½-inch in size, which he said should
be placed in a tub of hot lime and water in a “semi-fluid
state” (210). The craftsman should retrieve the material
as needed, Millar continued, and then
“quickly and evenly throw or dash [it] on with a
‘scoop’ or hollow trowel, then brush [it] with liquid
to give a uniform tint. A good craftsman can dash
the shingle very regularly, and leave the face of
the work with a uniform, though rough surface.
The dashing should be begun at the top, gradually
working down, taking in all angles and sides of
panels” (210).
Today, though some craftsmen continue the tradition of
dashing, it is more common for the aggregate to be added
to the mixture before application and painted after it
dries (see Fig. 10).
Though weatherproof by nature, renders were often
made even more protective with coats of wax or oil
(Grimmer). Millar provided instructions for different
tints to add to the dash, if desired. For a buff color, for
example, he suggested craftsmen add copperas and
fresh cow manure, noting that adding an alum solution
“will give brilliancy and permanency to the colours”
(558). Though the terms were (and still are) often used
interchangeably, when textured render is left natural or
tinted, it is generally called pebbledash (Fig. 4) and when
it is painted it is called roughcast (Fig. 5).
Evolution of Binders
Millar notes that the Egyptians, Greeks, and Romans
all used plaster “of most exquisite composition” (4).
Ancient builders used plasters bound with either burnt
gypsum, a naturally occurring, crystallized mineral
mined from ancient lake and sea beds, or lime, a
chemical compound formed by grinding and heating
limestone (4). Quicklime—or ground and heated lime
ready to be mixed for plaster—is highly reactive and
must not be allowed contact with the air before it is
time to mix it with water (a process called slaking the
lime), and the resulting plaster takes several months to
dry completely. On the other hand, natural gypsum-based
cements, like plaster of Paris, cure quickly, set
in minutes, dry completely in two to three weeks, and
make a more rigid plaster.
However, there were downsides to gypsum-based
plaster, including vulnerability to water damage
and a less-adhesive nature. Whereas lime plasters
“could survive occasional wind-driven moisture or
water wicking up from the ground. Gypsum plaster
needed protection from water. Furring strips had to
be used against masonry walls to create a dead air
space, [preventing] moisture transfer” (MacDonald,
4). As such, lime, which Millar called “one of the most
important materials in the building trades,” would
continue to be the main ingredient in renders of all
types throughout the nineteenth century (38). In Millar’s
manual—which has provided modern-day scholars and
practitioners insight into traditional Victorian methods
for mixing and applying various kinds of renders (as
well as their histories and relative strengths)—he noted
that “100 yards superficial of rough-casting (two coat
on lath),” called for “25 cubic feet of lime, 50 cubic feet
of sand, 16 lbs. of hair, and ¾ yard of prepared gravel
for the dash coat. A quarter tub of lime putty should be
mixed with every tub of gravel for the dash” (558).
The development of portland cement, however,
quickly made builders less dependant on lime renders.
Developed by a bricklayer and plasterer in Leeds,
England in 1824, it was first manufactured in the United
States in 1871 (Millar, 55). When Millar published
Plastering: Plain and Decorative in 1897, he noted that
portland cement could be substituted for the first layer
of coarse stuff (210). By the twentieth century, craftsmen
Fig. 6: A front elevation drawn by Smith c. 1900 for a
Montford home featuring a roughcast render (see detail).
Fig. 7: A Biltmore Village cottage featuring the signature
Richard Sharp Smith roughcast exterior.
UNCG The Historic Dimension Series: 4
had transitioned to stucco composed of mostly portland
cement bases mixed with a small quantity of lime
(Grimmer).
Millar notes that the advantages of portland cement
were “its hydraulic properties [i.e., its ability to
harden when combined with water], great strength at
comparatively early dates, its continually increasing
strength, and its power of carrying very large
proportions of sand or other aggregate when made into
mortar or concrete” (55). Grimmer also highlights the
ways in which renders improved after the introduction
of portland cement:
“No longer used just as a coating for a substantial
material like masonry or log, stucco could now
be applied over wood or metal lath attached to a
light wood frame. With this increased strength,
stucco ceased to be just a veneer and became a more
integral part of the building structure” (Grimmer, 3).
Ultimately, the more coarse stuccos were “ideal for a
portland cement render” (Taylor). More finely finished
stuccos made with cement often cracked quickly after
application because the heavy troweling needed to
achieve the smooth finish pulled the aggregate and the
moisture to the surface. According to British conservator
Jonathan Taylor, pebbledash and roughcasting mixed
with cement are less likely to crack because the
mixture does not require much troweling and the stone
aggregate actually strengthens the binding.
Assessment of Damage and Deterioration
Like other kinds of render, pebbledash and roughcast
are assumed to be more resilient and weatherproof than
plain stucco, but they suffer from many of the same
issues as its less-textured cousin. According to Grimmer,
“age and lack of maintenance hasten the deterioration
of many historic stucco buildings. Like most historic
building materials, stucco is at the mercy of the
elements, and even though it is a protective coating, it is
particularly susceptible to water damage” (1). Most often
the water infiltrates the building from joints and seams
in its construction— such as the roof, around chimneys,
and windows and doors—or rising damp. Underlying
issues should be taken care of before addressing the
necessary stucco repairs.
When assessing historic stucco of any variety, it is
important to determine what kind of base was used in
the original mixture. Lime renders are rarely used today;
however, using gypsum plaster to repair work originally
done with lime can be problematic. Experts caution that
binders behave differently, and if two different binders
are mixed (using gypsum plaster to repair historic lime-based
render, for example), the surface will soon crack
where the two come together (Howell).
Grimmer notes that it is important to watch out for
deterioration caused by previous badly done repairs
“particularly if executed in portland cement, which
tends to be very rigid, and therefore incompatible
with early, mostly soft lime-based stucco that is more
‘flexible’” (7-8). It is also important to be aware of
vibrations caused by nearby traffic or construction, as
well as foundation shifts and settlement. All of these
factors can contribute to failure of the material.
Once the stucco begins to crack, water accumulates and
can cause further damage from freeze-and-thaw cycles,
especially in harsh climates like Asheville. Taylor warns
that this can “cause render to fall away in sheets” or
allow salt crystals (left behind from evaporated water)
to grow in the substrate. To determine how extensive
the damage is, gently tapping the surface with a wooden
handle will identify unsound areas (Taylor).
Maintenance and Repair
Because of the general resilience of the material,
general preventative maintenance and monitoring for
deteriorating should keep textured renders sturdily in
Fig. 9: Small batches of concrete and aggregate are
mixed for application. If patching historic roughcast,
modern materials are acceptable, but care must be used.
Fig. 8: The Carolina Bed and Breakfast, located in
Montford Historic District in Asheville, which used
pebbledash in a recent renovation (Figs. 8-13).
UNCG The Historic Dimension Series: 5
tact. Harsh chemicals and pressure washers should be
avoided; if cleaning is absolutely required, the gentlest
means possible should be employed. Harsh methods can
cause the aggregate to break apart, causing the potential
for further damage.
Because stucco is often applied on top of masonry or
wood, it is possible that it is hiding deterioration that can
cause water to penetrate the structure. A close inspection
at the point of water entry should reveal underlying
problems. The render may have to be removed (as
gently as possible) in order for the issue to be resolved
and then re-applied.
Repair. Finding the materials for and/or the craftsmen
who are familiar with historic rendering techniques,
however, can be challenging. When repairing
pebbledash and roughcast renders, the heavy texture
is far more forgiving than stucco, and therefore, less
likely to show imperfections arising from mismatched
materials. Grimmer addresses the difficulty in accessing
historically accurate components in the NPS brief on
historic stucco. She encourages the use of substitute
materials, noting that “it may not be worthwhile, nor
in many instances possible, to attempt to duplicate all
of the ingredients,” unless authentic reproduction is
absolutely necessary (Grimmar, 8).
As noted, it is important to match the strength and
flexibility of the binder used in the historic material.
Research on the structure’s history might provide some
insight, though Grimmar warns that the timing of the
switch from lime to portland cement is imprecise. A
more accurate method is to analyze the historic stucco to
provide useful information on its basic ingredients. For
example, “a dilute solution of hydrochloric (muriatic)
acid will dissolve lime-based stucco, but not portland
cement” (8).
Products to avoid. Modern caulking products should be
avoided, as they tend to attract more dirt, making them
“highly visible and unsightly,” though a commercial
bonding agent can be used to fill hairline cracks.
(Grimmer, 9). Small cracks can be filled with a “thin
slurry coat consisting of the finish coat ingredients, or
even paint or whitewash” (Grimmer, 9). Larger cracks
will have to be cut out. Rarely does an entire wall
need to be recast. Whatever the case, the heavy texture
of roughcast and pebbledash requires slightly less
precision, though the difficult nature of the technique is
best executed by a skilled professional. When modifying
an existing structure (like the window being resized in
Figs. 13-15) or a new addition constructed, the plasterers
should be diligent in matching materials and colors of
the historic materials.
Patching. When patching is necessary, the area to be
repaired is often squared off; however, clearing off an
irregular-shaped section cut on an angle can sometimes
make the patch less obvious and encourage a stronger
bond between the historic and replacement render.
Grimmer stresses the need to use sharp tools (such as a
cold chisel, hatchet, diamond blade saw, or masonry bit)
when cutting away and clearing damaged stucco, lest
oversounding, or “breaking keys of surrounding good
stucco,” occur (Grimmer, 9).
A bristle brush should be used to clean the damaged
area, clearing away the loose render and aggregate
down to the lath or bare masonry. To ensure that the
patch forms a strong key, the area to be patched should
be cleared of all dirt, loose paint, and other contaminants
Fig. 10: The first layer of stucco is applied in small sec-tions
to mesh lath. Scratching the surface allows the
second, roughcast layer to form a key, or strong bond.
Fig. 11: Though it seems like it would be forgiving, the
messy job (see Fig. 1) of dashing the roughcast is dif-ficult
to master.
UNCG The Historic Dimension Series: 6
and, if the substrate is brick or stone, the mortar joints
should be scraped back approximately half an inch.
Deteriorated lath should be either repaired or replaced
with wire mesh. Grimmer instructs that the patch and
the old stucco must not overlap.
Removal. Homeowners not enamoured with the effect
of the textured stucco may wish to remove it. Though
revered in places like Asheville as a nostalgic, rustic
material, in some places—particularly the United
Kingdom—it has earned the reputation as a tacky,
drab cover-up for shoddy construction. According to
Taylor, one architectural critic wrote in 1962 that “‘one
often recoils with acute distaste from [pebbledash’s]
coarse and lumpy texture and its drab yellowbrown
colour.’ These views were widely shared by a generation
reacting to the architecture of the previous generation.”
In both the United States and United Kingdom, renders
have also been misidentified as “a sacrificial coating”
and removed to reveal underlying materials, such as
stone, brick or logs, that were always intended to be
covered (Grimmer, 1). While stucco can be successfully
removed, before undertaking such a project, research
should be conducted to determine the home’s original
design. Removing any sort of wall finish is a tedious task
that often damages the substrate, so caution is advised.
Asheville Specifications. Because of the importance
of pebbledash to the character of Asheville’s built
environment, the Historic Resources Commission
of Asheville & Buncombe County (HRC) is diligent
about its use and upkeep in the city’s historic districts.
The HRC includes information on the maintenance
and repair of pebbledash and roughcast renders in
design guidelines for neighborhoods where the style is
prominent, like Montford and Biltmore Village. These
common-sense suggestions—such as regular inspections
for water and vegetation damage, structural cracks,
and deterioration—reflect the Secretary of the Interior’s
Standards for Rehabilitation and Bernard Feilden’s
Ethics of Architectural Conservation.
The HRC encourages owners to “use the gentlest means
possible” when cleaning masonry (64). High pressure
washing of pebbledash is not allowed, as this causes the
aggregate to break off and allows moisture to permeate
the substrate. Repairs or replacement of damaged
materials must comply with “recognized preservation
methods for piecing-in, consolidating, or patching
damaged or deteriorated masonry” (65). The guidelines
mandate that replacement materials should “match
the visual and physical properties of the original” and
“new pebbledash should match original in texture and
application” (65-6).
To maintain the visual character of the historic districts,
HRC often requires owners to incorporate pebbledash
in renovations and additions. For example, when
James and Susan Murray applied for a certificate of
appropriateness for the expansion of their Montford
neighborhood bed and breakfast (a Richard Sharp
Smith-designed home clad in painted pebbledash, as
seen in Fig. 8), the HRC requested they cover one of the
walls with roughcast rather than the proposed wood-shake
siding (a material also common in the district).
Conclusion
While renders like roughcast and pebbledash are not
always popular with homeowners, they represent
a rich historic building material and technique that
should be preserved through regular upkeep and
repair when needed. In Asheville, in particular, its
prominent role in the region’s history and vernacular
architectural style enhances its significance. Given its
natural resistance to moisture and longevity, pebbledash
and roughcast require a relatively small amount of
effort and should be able to be effectively preserved by
Fig. 14: To match the historic render (right foreground),
the first layer must be set back to allow for the thickness
of the roughcast layer.
Figs. 12 (l) and 13 (r): To match the historic render (right
foreground), the first layer must be set back to allow for
the thickness of the roughcast layer.
UNCG The Historic Dimension Series: 7
following the Secretary’s Standards of Rehabilitation and the well-documented procedures for maintenance and restoration. When repairs or new application is needed, experts encourage the use of a professional in its application, as achieving the right balance of materials and perfecting the application is more difficult than it might seem.
Bibliography
Asheville-Buncombe Historic Resources Commission [HRC]. (2010) “Montford Historic District Design Re­view Guidelines.”
Bennett, Bob. (n.d.) “The Development of Portland Cement.” Retrieved 5 March 2013 from http://www.buildingconservation.com/articles/prtlndcmnt/prtlnd­cmnt.htm.
Bishir, Catherine W., Michael T. Southern, and Jennifer F. Martin. (1999) A Guide to the Historic Architecture of Western North Carolina. Chapel Hill: The University of North Carolina Press.
Carlisle, Daloni. (10 February 2001) “Pebbledash is ren­dered trendy.” The (London) Times, 19.
Howell, Jeff. “Property: Get really plastered with lime-and-hair.” The (London) Independent. Retrieved 11 April from http://www.independent.co.uk/news/business/property-get-really-plastered-with-limeandhair-1291626.html.
Gibson, Scott. (n.d.) “How to Repair Sagging Plaster Ceilings.” Retrieved 5 March 2013, from http://www.oldhouseweb.com/how-to-advice/how-to-repair-sag­ging-plaster-ceilings.shtml.
Grimmer, Anne. (n.d.) “The Preservation and Repair of Historic Stucco.” National Park Service Preservation Brief #22.
Gurley, Robert M. (1994) Richard Sharp Smith. Thesis, University of South Carolina.
MacDonald, Mary Lee. “Repairing Historic Flat Plaster Walls and Ceilings.” National Park Service Preservation Brief #22.
Marshall, Alli. (September 24, 2008). “Working on a Building.” Mountain Xpress. Retrieved from http://www.mountainx.com/article/19782/Working-on-a-building.
Millar, William. (1905) Plastering: Plain and Decorative. London: B.T. Batsford.
Murray, Susan. (March 24, 2012) “Pebble Dash at the Carolina Bed & Breakfast.” Retrieved from http://www.carolinabb.com/2012/03/pebble-dash-at-the-carolina-bed-breakfast/.
“Pebbledashing Trade Application Guide.” (n.d.) Re­trieved 5 March 2013, from http://www.exterior house­painters.com/painting.pebbledash.php.
Southern, Michael T., ed. Asheville’s Historic Montford. (1985) Asheville: The Preservation Society of Asheville & Buncombe County.
Taylor, Jonathan. (n.d.) “Edwardian Pebbledash and Roughcast.” Retrieved 5 March 2013, from http://www.buildingconservation.com/articles/pebbledash/pebble­dash.htm.
_____. (n.d.) “Tools of the Trade.” Retrieved 5 March 2013, from http://www.building conservation.com/ar­ticles/toolsoftrade/toolsoftrade.htm.
Image Credits
Figs. 1, 8, 9, 10, and 11: Courtesy of Carolina Bed and Breakfast.
Fig. 2: Photo by “Anguskirk” via Flickr Creative Commons < http://www.flickr.com/photos/anguskirk/7164173075/>
Fig. 3: Photo by “bluekdesigns” via Flickr Creative Commons < http://www.flickr.com/photos/bluekdesign/3929984207/>
Fig. 4: Photo by Jonathan Taylor < http://www.flickr.com/photos/12624116@N03/6966547730/>
Fig. 5: add user name, (Flickr Creative Commons, www.flickr.com)
Fig. 6: Richard Sharp Smith; “Cottage - Chestnut St. - For Miss Annie West--Front Elevation;” Richard Sharp Smith Collection (aam_RS); item no. aam_RS0316_0001; NCSU Libraries’ Digital Collections: Rare and Unique Materials; Retrieved 10 April 2013 from http://d.lib.ncsu.edu/collections/catalog/aam_RS0316_0001
Fig. 7: Photo by “Teemu008” (Flickr Creative Commons, www.flickr.com)
Figs. 12-14: Photos from Pegasus Plastering <http://www.pegasusplasterers.co.uk/>
Special Thanks To James and Susan Murray, Carolina Bed and Breakfast, Asheville, North Carolina (www.carolinabb.com)
Stacy Merten, Director, Historic Resources Commission of Asheville & Buncombe Co.
Pegasus Plastering, London, England (www.pegasusplaster­ers.co.uk)
Jack Thomson, Preservation Society of Asheville and Bun­combe County
The Historic Dimension Series is a collection of briefs prepared by UNCG students under the direction of Professor Jo Ramsay Leimenstoll. For information on other topics in the series please visit the website at go.uncg.edu/hds