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Preserving Historic Ornamental
Plaster
David Flaharty
From the time America
struggled for a new identity as a constitutional
republic--and well into the 20th century--its architecture
and its decorative detailing remained firmly rooted in the
European classicism of Palladio, Wren, and Mansart.
Together with skilled
masons and carpenters, ornamental plasterers saw their
inherited trade flourish from the mid-18th century until the
Depression years of the 1930s. During this two hundred year
period, as the Georgian and Federal styles yielded to the
revivals--Greek, Rococo, Gothic, Renaissance, and
Spanish--decorative plaster reflected each style, resulting
in the wide variety of ornamentation that survives. The
traditional methods of producing and installing interior
decorative plaster were brought from Europe to this country
intact and its practice remains virtually unchanged to this
day.
Like flat walls and
ceilings, historic ornamental plaster is made of gypsum and
lime which are stable and durable materials. An extremely
versatile material, plaster can be modeled, cast, incised,
colored, stamped, or stencilled. However, as an integral part
of the building system it is subject to the typical problems
of water intrusion, structural movement, vibration and
insensitive alterations, both incrementally and from adaptive
use projects. This Preservation Brief has been prepared to
assist property owners, architects, contractors, and Federal
agency managers in identifying the causes of ornamental
plaster failure, specifying repair and replacement techniques
and engaging qualified professionals to do the work. The
scope of this Brief is limited to the repair and restoration
of existing ornamental plaster; certain forms of decorative
plaster such as scagliola, composition ornament, and
artificial Caen Stone are not addressed, nor is the design
and installation of ornamental plasterwork in new
construction. Finally, guidance on using substitute materials
to match the historic appearance of ornamental plasterwork--a
legitimate option within the Secretary of Interior's
Standards for Historic Preservation Projects--is not
discussed here, but will be the subject of another Brief on
interiors.
The Ornamental Plaster
Trade
Shop Personnel. As
builders and architects were hired by an increasingly
affluent clientele, ornamental plaster shops developed from
the single artisan operations of the 18th century into the
complex establishments of the early 20th century. American
plaster studios employed immigrant and, later, native
craftsmen (see Fig. 1). Plasterers' guilds were in existence
in Philadelphia in the 1790s. In 1864, a plasterers' union
was organized in the United States with members from the
British Isles whose work there had been limited to palaces
and churches. English and European craftsmen came to America
where the demand for their skills had increased by the
decade, offering them the unparalleled opportunity to open
their own shops. Over the years, plaster elements became so
popular in decorating interior spaces that a major industry
was established. By the 1880s, catalogs were available from
which property owners could select ornamentation for their
splendid new buildings (see Fig. 2).
Methods of Production.
Historically, ornamental plasterwork has been produced in two
ways: it would be run in place (or on a bench) at the site;
or cast in molds in a workshop. Plain plaster molding without
surface ornamentation was usually created directly on the
wall, or run on a flat surface such as a plasterer's
workbench and attached to the wall after it set. Ornament
such as coffering for ceilings, centers for light fixtures
(medallions), brackets, dentils, or columns were cast in hide
glue (gelatin) or plaster molds in an offsite shop, often in
more than one piece, then assembled and installed in the
building.
Decorative Plaster
Forms--Cornices, Medallions, Coffers. Three decorative
plaster forms in particular--the cornice, the ceiling
medallion, and the coffered ceiling--historically comprised
much of the ornamental plasterers' business. These forms
appear individually or in combination from the 18th to 20th
century, irrespective of stylistic changes.
For example, an elaborate
parlor cornice consisted of plain moldings made of gypsum and
lime run atop temporary lattice strips around the room.
Tooling for plain-run moldings called for a sheet metal
template of the molding profile mounted on a wooden "horse"
(see Figs. 3 and 4). Mitering was accomplished using a
plaster and lime putty gauge (mix) tooled with miter rods at
the joints (see Fig. 5). Decorative "enrichments" such as
leaves, egg and dart moldings, and bead and reel units were
cast in the shop and applied to the plain runs using plaster
as an adhesive (see Fig. 6). Painting, glazing, and even
gilding followed. Large houses often had plain run cornices
on the upper floors which were not used for entertaining;
modest houses also boasted cornice work without cast
enrichment.
Among the most dramatic
of ornamental plaster forms is the parlor ceiling medallion.
Vernacular houses often used plain-run concentric circles
from which lighting fixtures descended, usually hung from a
wrought iron hook embedded in the central ceiling joist. More
elaborate medallions were composed of shop-cast pieces, such
as acanthus foliage often alternating with anthemia or other
decorative designs. Medallions usually related stylistically
to the cornice ornament found in the room and could be
created with or without a plain-run surround (see Fig. 7). Of
particular importance to the art of ornamental plaster was
the mid-19th century double parlor plan. Architects often
specified matching medallions of robust proportions and
ornamentation. Later, in 20th century American Colonial
Revival architecture, architects called for Federal style
ceiling medallions. Some of the more successful were graceful
one-piece units, utilizing classical motifs such as garlands
and swags, and in their simplicity, reminiscent of Adamesque
designs of the 1760s.
Yet another significant
decorative form is the coffered ceiling. Coffering units were
cast in the shop or onsite, then installed with hanging wires
to form the ceiling (see Fig 8). Ceiling design varied from
period to period as to depth, panel shape, and ornamental
complexity. Not always flat, coffering is seen inside domes,
within barrel vaults and groin ceilings, along overhead ribs
and soffits. Rosettes are usually centered in the panels and
often enrich the intersections of elaborate stiles bordering
the panels. Flat ceiling coffers are generally identical in
reflected plan; on domed or barrel ceilings, coffers differ
from course to course so as to appear identical from various
sight lines. The finish treatment of a coffered ceiling
frequently exhibits the height of the painter's craft.
Foremost examples of ceiling coffering include the United
States Capitol, and Washington D. C.'s Union Station. As a
popular decorative form with inherent acoustical benefits,
the coffered ceiling is seen across the United States in many
large public spaces such as theaters, courthouses, railroad
stations, and hotels (see Fig. 9).
Unfortunately, these
supposedly enduring decorative forms created by ornamental
plaster tradesmen are subjected to the ravages of both nature
and man and, consequently, seldom remain as originally
designed. Minor changes of taste are perhaps the least
injurious to plasterwork. Considerably greater damage and
deterioration are caused by radical changes in building use
and poor maintenance practices. Fortunately, in most cases,
the form, detailing, and finish of historic ornamental
plaster can be recaptured through careful repair and
restoration.
Causes of
Ornamental Plaster Damage
Ornamental Plaster
Substrate. For flat plaster walls and ceilings, as well as
decorative forms, the system to attach interior plaster to
walls and ceilings primarily consisted of 1/4" x 11/4" wooden
lathing strips nailed 3/8" apart against studs and joists.
First a scratch coat consisting of sand, lime, and cattle
hair was troweled on the lath and pressed through the slots
so as to slump over and form "keys." Next, a brown coat was
applied to establish flat and plumb surfaces. The earliest
plasterwork consisted of two coats of lime and sand plaster;
later in the 19th century,
a third or finish coat was
applied that consisted of both lime and gypsum. Decorative
units were generally attached to the substrate using plaster
as an adhesive.
Signs of Failure. Failure
of the substrate is more typical than failure of the plaster
ornament itself. Among the reasons for deterioration,
structural movement (see Fig. 10) and water intrusion (see
Fig. 11) are the most deleterious. Buildings move and settle,
causing deflection and delamination which result in stress
cracking. These cracks often begin at the corners of windows
and doors and extend upward at acute angles (see Fig. 12).
Roof or plumbing leaks make finishes discolor and peel and
cause efflorescence, especially on plain-run or enriched
cornices. Unheated buildings with water intrusion are subject
to freeze-thaw cycles which ultimately result in base coat
and ornamental plaster failure (see Fig. 13).
In addition, keying and
adhesive properties may be further jeopardized by weak
original mixes (see Fig. 14) that were improperly applied.
Substrate failure typically results from faulty lathing or
rusty lath nails, causing ceilings to fall. In the 20th
century, vibration from heavy vehicular traffic, nearby
blasting, and even repeated sonic booms may contribute to
damaging ornamental plaster. Inadequate support in an
original design may also be to blame when particularly heavy
units have simply broken off over time (Fig. 15). Finally,
new mechanical systems, suspended ceilings and partition
walls insensitively installed in adaptive use projects, show
little regard for the inspired decorations of earlier periods
(see Fig. 16).
Repairing and Replacing.
Plaster failure is a matter of degree. For example, top coat
failure can be repaired by applying a new finish coat over a
sound early substrate. Also, if cracking or loss of all three
coats has occurred and is not combined with major structural
failure, it can be repaired much like flat wall plaster. For
ornamental plaster, however, repair beyond patching is often
equivalent to targeted replacement of entire lengths or
portions of run-in-place and cast ornamentation. Pieces that
are deteriorated or damaged beyond plain patching must be
removed and replaced with new pieces that exactly match the
existing historic plaster. For this reason, partial
restoration is often a more accurate term than repair. But
whichever term is used, it is not recommended that repair of
ornamental plaster be undertaken at any level by property
owners; it is a craft requiring years of training and
experience. A qualified professional should always be called
in to make an inventory of ornamental plaster enrichments and
to identify those details which are repairable onsite and
which should be removed for repair or remanufacture in the
shop.
Immediate Action
Once the cause and extent
of damage have been determined, treatments such as shoring,
stabilization, and limited demolition can begin, preparatory
to repairing or restoring historic ornamental plaster.
First, roof or plumbing
leaks must be repaired to eliminate the problem of water
intrusion. General structural repairs should be undertaken to
arrest building movement, which weakens the base coat
plasters to which the ornamental enrichments are attached.
Ornamental plaster deflection should be corrected by shoring
from below followed by re-anchoring (see Fig. 17).
Testing for poor adhesion
of base coat to lath or ornament to base coat, should be
conducted to reduce further loss of enrichment. Adaptive use
intrusions should be carefully removed to protect the
existing decorative plasterwork.
Code-required fire
suppression systems should be evaluated at this time. Modern
building codes may require heat/smoke/flame detectors and
automatic sprinkler systems of various types and
applications. Fire suppression systems as well as all
mechanical systems (HVAC, plumbing and electrical) systems
should be designed so that they accomplish their purpose with
minimal impact on the decorative plaster. Plumbing for an
automatic sprinkler system, for example, can be run above new
and existing coffering so that the sprinkler heads barely
protrude from the rosette centers in the coffered design.
Access should be provided for future system maintenance or
repair.
A 20th Century Shop
Tour--Personnel, Materials, and Processes
Before discussing how
decorative forms such as cornices, medallions, and ceiling
coffers are repaired onsite and in the shop by ornamental
plasterers, the "shop tour" explains traditional casting
processes used in conjunction with updated materials. A shop
tour can be exciting, but confusing to the layman without
some explanation of modeling, molding, and casting
activities. For a prospective client, a visit to the plaster
studio or site can be of value in choosing a qualified
plastering contractor.
Shop and Personnel.
Generally, a highly functional shop should look well
organized--that is, not in disarray with remnants of past
projects lying about to impede current production. Old molds
may be in abundance, but hanging from the wall or otherwise
"on file." Machinery (saws and drill presses) and hand tools
should appear well maintained. In short, one might evaluate
such a studio as one does an auto mechanic's shop: does it
inspire confidence? This is the time to look around and ask
questions. What is the shop's past project work experience?
Is the firm mostly involved in new construction work or total
reconstruction? More important than the way the shop looks,
is the personnel sufficiently experienced in making repairs
to historic decorative plaster? What about training and
apprenticeships? How did the staff learn the trade? The more
that is known about the total operation the better.
Molding Rubber.
Familiarity with contemporary molding rubbers is desirable.
There are several formulations currently on the market. In
the past, flexible molds were made with hide glue melted in a
double boiler and poured over plaster originals which had
been prepared with an appropriate parting agent. Of the newer
rubbers, latex (painted on the model coat by coat) is time
consuming and has little dimensional accuracy; polysulfide
distorts under pressure; and silicone is needlessly
expensive. Urethane rubber, with a 30-durometer hardness, is
the current choice. Urethanes are manufactured as pourable
liquids and as thixotropic pastes so that they can be used on
vertical or overhead surfaces. The paste is especially useful
for onsite impressions of existing ornament; the liquid is
best used in the shop much as hide glue or gelatin was
historically. Urethane rubber has the ability to reproduce
detail as fine as a fingerprint and does not degrade during
most ornamental plaster projects. No flexible molding
material lasts forever, so spare casts should be maintained
for future remolding.
Molding Plaster. Molding
plaster will also be in evidence; it is the product most
similar to that used historically. This plaster is finely
ground to accept the detail of the rubber molds, not so hard
as to prohibit tooling, and combines readily with finish
lime. High-strength plaster is available in varying
densities, some with added components for specific purposes.
Most shops maintain these varieties, but use molding plaster
for typical work.
Sheet Metal Templates.
The contractor's familiarity with sheet metal is critical.
Accurate template blades are required to reproduce both
straight and curved sections of moldings (see Fig. 3, above).
The blades must be carefully cut, filed, and sanded in order
to form exact reproductive units. A tour of a sizeable shop
will include observation of running techniques and the
results of this activity should be much in evidence.
Regardless of size, these runs should be smooth and true when
made by qualified
craftsmen.
Models. Models, whether
of capitals, cornices, medallions or cartouches, are made as
whole units or in parts depending on project demands.
Completeness, accurate dimensions, and attention to historic
styles are essential ingredients of successful models. Each
part of a model has a name, i.e., dentil, guilloche, rinceau
or bolection molding, modillion, egg and dart, and the
designers and restorers of these ornaments should know their
names. Failure to identify these parts correctly should be of
concern to a prospective client.
Molds. Molds are
"negative forms" produced from completed models. Simple flood
molds require a separator or barrier coat over the original
and a surrounding fence to prevent the liquid rubber from
leaking out. Larger or more complicated molds are made in
pieces or with a layer of rubber supported by a plaster shell
or mother mold attached to a wooden or metal frame. Following
completion of a successful mold, the original model is
discarded because it is now possible for it to be accurately
reproduced.
Casting the Molds.
Casting operations should appear clean and efficient. A
skillful caster's output can be voluminous and often looks
effortless as it is being produced. Raw materials are close
at hand, molds are rarely without curing plaster in them,
production is stored so as not to warp while it is still wet
and each cycle, from mixing to pouring, setting, and
demolding is accomplished so as not to waste time or break
plaster casts. A good caster generally obviates the need for
a finishing department.
Two other aspects should
be noted. Shipping facilities are critical to move the
product to the restoration site safely. Drawing and design
space should be separate from the production floor. In
summary, the modern ornamental plaster shop inevitably looks
quite different from that pictured earlier in this
Preservation Brief (see Fig. 1, above), but, with the
exception of contemporary tools and materials, the operations
are the same. The following sections discuss how repairs are
made by today's plaster tradesmen.
Repairing
Historic Ornamental Plaster
Cornice. A plain run or
ornamented plaster cornice which has undergone damage or
severe deterioration can often be repaired. Footage which is
beyond repair should be identified and be carefully
demolished to expose the underlying structure beneath to
which the molding was secured. To replace the missing
lengths, the first step is to obtain a cross-section, or
profile, through the cornice from finish ceiling to finish
wall lines. This is best accomplished using one of these
methods:
1. A section through the
cornice may be determined by sawing through the molding,
inserting a sheet metal blank in the slot and tracing the
profile directly on the template. This is considerably more
accurate than the profile gauge, but will require repointing
the saw kerf; alternatively, the cut may be made on one of
the deteriorated pieces, provided it was removed as an intact
unit.
2. The section may be
obtained by making a thixotropic rubber impression of the
molding, casting the result in fresh plaster and sawing
through the cast to transfer the cross-section to a sheet
metal template.
With the section
determined, it is drawn onto 22-gauge galvanized sheet metal,
cut with tin snips and carefully filed to the line. The
template is checked periodically against the original profile
to assure a perfect match. With the template blade finally
complete, it is nailed to stock and slipper (see Fig. 3,
above), ready for running the replacement footage.
Short lengths of new
cornice are best run on a bench using gypsum and lime; the
reproduction molding should be somewhat longer than the
required length (see Fig 18). The new footage is cut and fit
in place to match the existing cornice, then securely
countersunk-screwed to studs, joists and/or blocking. The
resulting joints are pointed with flat mitering rods, flush
with adjacent members (see Fig. 5, above).
Longer lengths of cornice
may be run in place, much as they were historically. Care
should be taken that the position of the running mold engages
with the existing work at either end of the run. Yet another
method is to bench run the cornice to five or six feet, make
a rubber mold of the model, and precast the replacement parts
either at the site or in the shop.
If the damaged cornice is
ornamented, samples of the enrichment should be removed,
making sure that whole original units are obtained. This is a
difficult process, since these units were stuck into
plain-run recesses called "sinkages" using plaster as an
adhesive. In order to insert a flat chisel behind the
ornament to break the bond, some units may have to be
sacrificed. Sacrifice should be minimal. The excised
enrichment should then be removed to the shop for rubber
molding and casting either with or without the paint buildup,
depending on the demands of the project. Whereas molding with
several layers of paint make it hard to discern new casts
from originals, paint-stripped molding reveals the remarkable
talents of the period model-makers. As noted, contemporary
rubber materials have "fingerprint detail" capability. Modern
casts are then applied to the new or original runs, again
using plaster as an adhesive.
Ceiling Medallion.
Ceiling medallions are often in greater jeopardy than
cornices because the joist-lath-base-coat support system is
susceptible to deflection and the force of gravity. The
problems of ceiling failure are more frequent in the centers
of parlors because circular-run and shop-cast ornament is
often quite heavy and was not historically attached with any
additional mechanical fasteners such as bolts and
screws.
If the lath or keys have
failed, plaster ceiling ornament may be saved, in whole or in
part, by removing floor boards above, then drilling and
injecting each lath with an elastic acrylic or epoxy material
to reattach plaster to lath, and lath to the joists. This is
a recently developed procedure which should only be
undertaken by experienced professionals. The consolidation
and reattachment process has been used successfully in period
structures with dramatic results when important plaster and
painted surfaces would otherwise have been lost.
Historic lighting
fixtures often hung from elaborate ceiling medallions. When
these fixtures were later converted to gas and electrical
service, the central ornamental plaster canopies were
sometimes damaged by insensitive tradesmen. More recent
adaptive use projects may have caused additional
damage.
Damaged ceiling
medallions (see Fig. 19a) can be repaired by carefully
removing representative plaster ornamentation, molding and
recasting in the shop (see Fig. 20) and replacing the new
enrichments so that they align perfectly with the original
pattern. Polyvinyl acetate bonding agents are applied to the
background and ornament so that the adhesive plaster grips
tightly. Alternatively, a severely damaged medallion (see
19b) can be replaced using the fragments as physical
documentation to cast a visually accurate replacement.
Sections of plain-run
circular molding may also be repaired by determining a
section through the run and the radius from molding to pivot
point. As with cornices, the run should be made on a bench to
a length greater than required, then cut and fit in place.
Circular run sections are installed using plaster adhesives
on bonded surfaces or modern construction adhesives after
referring to manufacturers' instructions as to whether the
adhesive is recommended for use on wet or dry materials.
Coarse-threaded, galvanized screws are often countersunk to
aid the bond; if possible, the screws should be inserted at
points that will ultimately be covered with cast
enrichments.
Ceiling medallions
frequently appear in matching double parlors. It is not
unusual for one ceiling to fail while its mate remains
undamaged. The flat plastered ceiling over the location of
the missing medallion often has a "ghost," confirming that a
ceiling medallion once ornamented the parlor. The missing
medallion may be remanufactured by securing a section,
dimensions, and samples of cast enrichments from the
surviving ornament and accurately following the original
procedure (see Fig. 7, above). The ceiling on which the new
work is to be set should be examined for its soundness and,
if necessary, relathed (with self-furring metal lath) and
plastered. The pivot point for a circular run is screwed into
a wooden block, force-fit into the center electrical box, and
removed after the run is completed.
After 1850, particularly
in the South, ceiling medallions were often designed with
cast ornament only; no plain-run surround was used. Repair of
such medallions proceeds as described above but without
bordering molding.
An important point needs
to be made about adding ceiling medallions (or any other kind
of ornamental plaster element) when there is a lack of
historical evidence. If there is no ghost mark or other
documentation, indicating a medallion once existed, then the
room should remain unornamented as it was historically.
Adding conjectural ornamentation of any type or material
(i.e., shop-cast or glass fiber reinforced plaster or
polystyrene foam substitutes) can create a false sense of
historical development contrary to the preservation
principles stated in The Secretary of the Interior's
Standards for Historic Preservation Projects. However, if
there is clear indication that a ceiling medallion once
existed, but there is inadequate documentation for its
replacement, a medallion compatible with the room's historic
character may be considered. Professional advice should be
sought.
Coffered Ceiling. Like
cornices and medallions, coffered ceilings suffer from poor
maintenance practices and structural problems; however, these
individually cast ceiling units are particularly vulnerable
when a building is being rehabilitated and great care is not
taken in executing the work. In the most serious of cases,
portions of a roof can collapse, dropping heavy debris
through the hanging coffering panels, and demolishing large
portions of the ornamentation (see Fig. 21).
But even this level of
damage can usually be remedied by restoration professionals.
Immediate action calls for shoring the areas adjacent to the
damage, and inspecting the hanging apparatus for unforeseen
detachment and deflection. New channel iron is used to
stabilize the existing coffers and ties reinforced, as
necessary. An intact coffering unit is then identified and
carefully removed to a casting shop for molding and casting
(see Fig. 22). When rehung, the units are painted to match
the historic coffering (see Fig. 23).
Coffered ceilings appear
with plain run or enriched cornices. In most cases it is
recommended that the cornice be repaired first in order to
achieve straight and level moldings. Then the damaged coffers
should be replaced with the matching new coffers and the
joints between pointed. Access from above is critical.
Finding and
Evaluating a Contractor
When ornamental plaster
damage or deterioration has been identified, the historic
property owner, architect, or developer should secure the
services of a reputable restoration contractor before
proceeding further. It is clear as more and more projects are
undertaken, that there is a wide disparity of skills within
the trade today. This is partly due to the introduction of
gypsum board as a substitute for traditional plastering. As
gypsum board became popular after World War II, plasterers
saw the demand for their skills decline. Plastering
techniques were forgotten because they were often not passed
down within shops and families. However, ornamental plaster
studios have seen a resurgence in demand for their services
in the last decade, particularly as more historic buildings
are rehabilitated (see Fig. 24).
Locating an experienced
contractor who is suitable for your particular project is the
goal. First, many professional preservation organizations can
provide references for suitable restoration contractors.
Local plasterers' unions should also be able to identify
contractors with experience in ornamental plaster restoration
projects. Architects with preservation and restoration
project experience may recommend contractors they feel have
done a good job for them in the past. Museums with period
rooms have engaged craftsmen to assemble the backgrounds for
display of antique furniture and decorative arts. Finally,
historical societies, either national, state, or municipally
organized, may have funded projects which repaired and
restored ornamental plaster.
Once several contractors
have been identified, their specific abilities need to be
evaluated. Prospective contractors should be invited to visit
the job site to see and define the scope of work; written
proposals, including prices, from all bidders, are essential
for comparison. References should be provided and
investigated. An outside consultant may be engaged or an
informal adviser designated to aid in evaluating the
experience and proposals of the bidders. To get a total
picture, a completed project should ideally be visited by the
prospective client with the contractor present to answer
questions which often arise.
Finally, although this
may not always be achievable, the bidder's studio may be
visited, preferably on a normal working day (see A 20th
Century Shop Tour, above.) Alternatively, the bidder may be
visited while working onsite. Some ornamental plasterers
simply do not have shops. They prefer to cast onsite,
adhering the casts while the plaster is wet, and coordinating
the job closely with the architect, who inspects each unit as
it is cast and before it is installed.
Conclusion
Decorative plasterwork is
usually a component of the historic character of interiors
and, consequently, The Secretary of the Interior's Standards
for Historic Preservation Projects call for its protection,
maintenance, and repair. Where decorative plasterwork has
deteriorated beyond repair, it should be replaced to match
the old. Based on physical documentation, both repair and
replacement can be accomplished using traditional molding
plaster and casting procedures, together with the best of the
modern molding materials available. Once a "lost art" after
the Depression years, the skills of today's ornamental
plasterers are increasingly in demand as part of historic
preservation project teams. The ingenious and inspired
decorative work created by our earlier architects and
artisans can now be assured an extended life.
Bibliography
Bankart, George. The Art
of the Plasterer. London: B. T. Batsford, 1908.
Dalton, Byron William.
Practical Plastering and Cement Finishing and Related
Subjects. Chicago, Illinois: Byron William Dalton,
1949.
Flaharty, David.
"Ornamental Plaster Restoration." Fine Homebuilding. No. 57,
December, 1989/January 1990, pp. 3842.
Garrison, John Mark.
"Decorative Plaster: Running Cornices." The OldHouse Journal.
Vol. XII., No. 101, December, 1984, pp. 214219.
----------. "Casting
Decorative Plaster." The Old-House Journal. Vol. XIII, No. 9,
November, 1985, pp. 186189.
Gypsum Construction
Handbook. Chicago, Illinois: United States Gypsum Co.,
1986.
Harris, Cyril M., editor.
Illustrated Dictionary of Historic Architecture. New York:
Dover Publications, 1983.
Millar, William.
Plastering, Plain and Decorative. London: B. T. Batsford,
1897.
Phillips, Morgan.
"Adhesives for the Reattachment of Loose Plaster" Association
for Preservation Technology Bulletin, Vol. XII, No. 2,1980,
pp. 3763.
Van den Branden, F. and
Hartsell, Thomas L. Plastering Skills. Homewood, Illinois:
American Technical Publishers, Inc., 1984.
Acknowledgements
Thanks go to the
technical experts in the field who reviewed and commented
upon the draft manuscript: M. Earle Felber, Andrew Ladygo
(Jefferson Poplar Forest), Lee H. Nelson, FAIA, Gilbert Wolf
(National Plastering Industries), and Stephen Zychal
(Ornamental Plastering, Inc.). This Brief was developed by
the Technical Preservation Services Branch, Heritage
Preservation Services Division, National Park Service, U.S.
Department of the Interior, Washington, D.C. It is not
copyrighted and can be reproduced without penalty. Normal
procedures for credit to the author and the National Park
Service are appreciated.
Last Modified:
January 30, 1998
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