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Moravian College • Preservation Master Plan
off after treatment. Failure to do so will cause
premature paint failure of the new coating.
Sandblasting is extremely harmful to historic
material surfaces and should never be used. It
leads to water penetration and deterioration.
Water-blasting is only appropriate for loose paint
on masonry surfaces if used at low pressure
(150-200 psi maximum). Pressure-washing wood is
detrimental as it raises the grain and forces moisture
into the walls. It leads to paint failure, wood decay,
and structural problems.
Propane or butane torches, electric hot-air guns,
and electric heat plates are never recommended for
paint removal because they can scorch the surface
of the wood and ignite debris behind clapboards.
Likewise, electric sanders can cause irreversible
damage by removing the wood surface in addition
to paint.
Substrates to be painted must be properly prepared
and primed. Manufacturer recommendations
must be followed for each type of substrate to be
painted. Primer helps the finish coats bond to the
new and previously-painted surfaces and combats
deterioration caused by moisture absorption.
When choosing a paint system, pick one that is
appropriate to the existing coating, the surface to be
painted, and the site’s environmental microclimate.
The extra cost of high-quality paint is a good
investment because it maintains a better surface
for a longer period. New paint must be compatible
with the old paint. Surfaces previously painted
with oil-based paint should only be repainted
with oil paint. Alkyd and oil paint should not be
combined in multiple layers. Apply paint with a
brush, because spray-on paint has poor adherence,
a thinner coat, and greater failure rate.
Historic Paint Colors
While paint offers an important protective coating
for architectural materials, it also provides valuable
information on the aesthetic intent and changing
tastes over time. Often when a historic building is
restored or renovated, there is a desire to repaint
using original or historically appropriate colors.
When a historically accurate restoration is needed,
a materials conservation professional should be
engaged to do a paint analysis or seriation study.
This study analyzes a paint sample in cross-section
using a microscope under special lighting conditions
to study the colors and sequences of all the coating
layers (seriation) on the surfaces of architecturally
significant elements and building surfaces. Historic
paint analysis can aid in the investigation of the
history and development of a building, as well as
provide information on coatings applied over time.
It is valuable in determining appropriate colors for
repainting.
Alternatively, for less sensitive spaces or simpler
finishes, it may be appropriate to choose from a
palette of period colors for repainting. Prior to the
nineteenth century, the color palette was typically
confined to natural colors, such as grays, buffs,
tans, ochre yellows and iron oxide reds. Bright
colors were restricted to greens and Prussian blue.
Care was taken to produce high gloss finishes,
particularly on woodwork. In the early nineteenth
century, new colors became available, including
chrome green and yellow and reds. The color
palette was slightly brighter and less gray. New
paint formulations brought about a fashion for
low-gloss finishes circa 1830. Factory-made paints
became widely available circa 1875 during a time of
exuberant color choices in the Victorian era. Tertiary
colors, a mix of secondary colors, such as olives
and red-browns, were popular. High gloss finishes
were used on woodwork; low-gloss paints were
used on wall surfaces. The turn of the century saw
a pendulum swing back to subdued colors with the
growing popularity of the Classical Revival styles.
In addition to color, other factors affect the
appearance of historic paints and must be
considered when applying new paint. Prior to
the widespread commercialization of paints circa
1875, paints tended to have coarser pigment grains
causing an unevenness of color. Unless the paint
layers were later rubbed smooth, brush marks
were often visible; the type of brush used left
distinctive lap and brush marks. The content and
thickness of the binder affected the final gloss level.
It is important to understand that gloss level and
application methods, as well as color, affect the
final appearance of paint.
9.11 Interiors
Much of the activity surrounding architecture takes
place on the interior. Interiors offer rich histories
about the use of the building over time. Pristine,
unaltered interiors may reveal a specific aesthetic
of a certain era, use, or owner. Interiors that have
been altered by each succeeding generation present
tales of change and technological improvements.
John Milner Associates • October 2009 • Chapter 9 • Building Guidelines • 312