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

Moravian College • Preservation Master Plan
• Capacity to shed rainwater during major rain
events without ponding.
• Unobstructed flow of water from the roof to
the ground and away from the building.
• Overall watertight roof surfaces.
• Watertight, free-flowing gutters and drains.
• Intact flashing around chimneys, parapets,
dormers, skylights, and valleys.
• Roof venting to prevent moisture
condensation.
• Drainage system that carries water away
from the foundation.
Inspections should include a comprehensive survey
to identify potential problems. Evidence of any of
the following conditions should trigger an in-depth
diagnosis and remediation.
• Ponding water at roofs and gutters.
• Excessive water runoff or overflowing
gutters.
• Water escaping between the seams of
downspouts.
• Rotted wood and peeling paint, especially at
wood cornices.
• Movement or cracking in masonry walls and
surfaces.
• Efflorescence on masonry surfaces.
• Missing or deteriorated mortar joints.
• Interior water penetration such as
cracking, plaster failure, powdery residue,
efflorescence, and dampness.
• Wood-destroying insects.
• Biological growth at foundation walls or at
adjacent surfaces.
• Soil erosion at the foundation and around
downspouts and boots.
Chimneys are subject to the same forces of decay
that affect other masonry features, and should be
inspected on an annual basis for leaning or cracking,
deteriorated brick or masonry, failed pointing and
flashing, faulty flue liners, and bird nests and other
intrusions. If in active use, interior soot and residue
should be cleaned annually.
Roof and Roof Drainage System
Repair
The baseline preservation approach is to repair
deteriorated roof components, features, and
materials promptly. Repair of deteriorated sections
of historic roofing material should be considered
before complete replacement. Leaky roofs can be
temporarily covered with plastic tarpaulin or roll
roofing nailed in place. Plastic drainage pipes can
be used to temporarily redirect water drainage
and several buildings at Moravian’s North Main
Street campus have their downspouts connected
to PVC pipe lengths. However, these are not a
permanently acceptable solution. Without this
type of intervention, the deterioration of surviving
building materials will be accelerated. However,
implementation of appropriate repairs should
be the highest priority whenever roof and roof
drainage systems are discovered.
Repair, including materials and workmanship,
should be executed in-kind to match historic
conditions. For example, copper gutters should
be replaced with copper, and galvanized with
galvanized. Significant materials should be
replaced to match the historic, especially on visible
roof surfaces. The gutter profiles and mounting
system should be consistent with the historic
versions. When in-kind replacement is not feasible,
replacement materials should match the visual and
physical characteristics of the historic roof system.
Repairs should be made using building-appropriate
materials and techniques that are meant to last for
the long-term and are not simply a short-term fix.
For example, patches and roofing compounds do
not solve the real problem; they are subject to early
failure and are often unsightly. Likewise, the use
of inappropriate contemporary materials should
be avoided in the repair of historic roofs. This is
particularly unadvisable when the replacement
material has a much shorter service life than the
historic material, i.e. using asphalt shingle to
replace historic slate roofing.
Slate Roofi ng
Slate is a common material for historic building
roofs at Moravian College, and some of the
buildings on campus still retain their original
historic slate. Improvements in transportation led
to an expansion of the slate industry, which peaked
around 1890-1914; however, slate has always been
a popular durable roofing material for institutional
John Milner Associates • October 2009 • Chapter 9 • Building Guidelines • 300