Moravian Preservation Master Plan.indb - Society for College and ...

Moravian College • Preservation Master Plan
the roofs and away from buildings causes multiple
and expensive deterioration problems in wood and
masonry walls. Roof drainage systems should be
holistically evaluated as an architectural, landscape,
and civil engineering issue. This evaluation should
investigate how water drains from the roofs, where
the water runoff falls to the ground, and how the
water is carried away from the building.
Historic gutters and downspouts should be replaced
in-kind to match all visual qualities including
materials, profiles, and details. Replacement
gutters should not alter the character of the
building’s architectural trim. Type-K (moldingshaped)
corrugated gutters and downspouts are
not appropriate on historic buildings. The use of
synthetic materials such as PVC and vinyl is not
recommended; they are incompatible with the
historic context of historic buildings at Moravian
College and have a short life-cycle. Galvanized
steel gutters and downspouts should only be used
to replace steel. Gutter guards should be considered
to reduce the collection of leaves and other material.
Because of the winter climate in Bethlehem, all
sloping roofs should have snow guards above
the eaves and up the lower portion of the roof to
prevent snow and ice from falling on pedestrians.
The placement and quantity of downspouts on
historic buildings should be carefully planned.
They should be securely attached to the wall
with a sufficient number of anchors. Splash
blocks or downspout extenders should be placed
beneath downspouts to carry water away from
the foundation and to limit soil erosion and
subsidence. Downspouts should not interrupt
or cross significant features such as cornices,
pilasters, or trim. All historic buildings should
have downspouts adequate to shed water from the
entire roof. They should also be put in unobtrusive
locations to the greatest extent possible. Modern
downspout extensions should be unobtrusive to
avoid visual impacts on the historic building and
its immediate setting.
Existing connections to underground drainage
pipe systems should also be tested; the clay tile
pipes typically used in the early- to mid-twentieth
century grow brittle with age and are prone to
cracking and breaking. Soil erosion at boots is
usually a sign of clogged or broken underground
connections. Below-grade pipe replacement with
modern PVC pipe is appropriate. When replacing
underground drain systems involving excavation
in historic areas, particularly at the Priscilla Payne
Hurd campus, consultation with archeologists
should take place before and during work.
Rooftop Additions and Attachments
New rooftop construction is a sensitive issue
in any historic building project. Large-scale
rooftop additions or equipment installations are
inappropriate on most historic buildings. Even
small rooftop additions alter the height, profile,
and overall exterior character of a building and
are not recommended. Only small, low-profile
mechanical equipment should be considered for
rooftop mounting on historic buildings, and then
only in a secondary location. Visibility is a key
issue; sight lines from nearby buildings, streets, and
other vantage points should always be evaluated.
In general, elevator overruns and areas of fire
refuge on historic buildings usually involve minor
changes. Nonetheless, they should be studied
for the overall visibility from all viewpoints and
compatibility with the building’s historic materials
and visual qualities.
Roof Replacement or Alteration
All historic roofs eventually need major or total
replacement. Skilled maintenance staff or roofing
contractors should carefully examine gutters,
leaders, valleys, and flashing before determining
that wholesale roof replacement is necessary. If
replacement is required, the historic materials
should be replaced in-kind, matching the existing
in color, texture, size, profile, seaming, patterning,
proportion, and other visual qualities. Slate and
tile roofs are durable and can last for many years
if well maintained. Traditional roofing materials
are expensive, but a life-cycle cost analysis
demonstrates that their use is actually very
cost-effective; for example, slate typically lasts for
a hundred years, while the average asphalt shingle
lasts about twenty years.
Slate roofs were installed on historic buildings
for both their visual appeal and longevity. Slates
vary in color, shape, pattern, and detailing, and
should always be replaced in-kind. Compatible
contemporary roofing systems, such as synthetic
slate, are readily available, but their cost is
comparable to the traditional material. Variation
from the existing slate type in making roof repairs
can be deleterious to the existing roof structure
and detract from the integrity and aesthetics of
the historic building. Generally, replacement of
John Milner Associates • October 2009 • Chapter 9 • Building Guidelines • 302