Identify, Retain and Preserve
Identifying, retaining, and preserving roofs--and
their functional and decorative features--that are important
in defining the overall historic character of the building.
This includes the roof's shape, such as hipped, gambrel,
and mansard; decorative features such as cupolas, cresting
chimneys, and weathervanes; and roofing material such
as slate, wood, clay tile, and metal, as well as its
size, color, and patterning.
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These slate and copper mansard roofs are distinctive
features of their urban setting and need to be
retained and repaired, or if too deteriorated to repair, replaced in kind to match. Photo: NPS files.
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Radically changing, damaging, or destroying roofs which
are important in defining the overall historic character
of the building so that, as a result, the character
is diminished.
Removing a major portion of the roof or roofing material
that is repairable, then reconstructing it with new
material in order to create a uniform, or "improved"
appearance.
Changing the configuration of a roof by adding new
features such as dormer windows, vents, or skylights
so that the historic character is diminished.
Stripping the roof of sound historic material such
as slate, clay tile, wood, and architectural metal.
Applying paint or other coatings to roofing material
which has been historically uncoated.
Protect and Maintain
Protecting and maintaining a roof by cleaning the
gutters and downspouts and replacing deteriorated flashing.
Roof sheathing should also be checked for proper venting
to prevent moisture condensation and water penetration;
and to ensure that materials are free from insect infestation.
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This new step flashing overlaps the next in
a downward slope to shed water draining down the
face of the chimney and the roof. Photo: ©
John Leeke.
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Providing adequate anchorage for roofing material
to guard against wind damage and moisture penetration.
Protecting a leaking roof with plywood and building
paper until it can be properly repaired.
Failing to clean and maintain gutters and downspouts
properly so that water and debris collect and cause
damage to roof fasteners, sheathing, and the underlying
structure.
Allowing roof fasteners, such as nails and clips to
corrode so that roofing material is subject to accelerated
deterioration.
Permitting a leaking roof to remain unprotected so
that accelerated deterioration of historic building
materials--masonry, wood, plaster, paint and structural
members--occurs.
Repair
Repairing a roof by reinforcing the historicmaterials
which comprise roof features. Repairs will also generally
include the limited replacement in kind--or with compatible
substitute material--of those extensively deteriorated
or missing parts of features when there are surviving
prototypes such as cupola louvers, dentils, dormer roofing;
or slates, tiles, or wood shingles on a main roof.
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After removing the deteriorated slate and sliding
the new slate into place, it is secured with a
copper nail. A copper bib (shown here) is formed
to protect the newly created nail hole. Finally,
a slate hammer is used to push the bib in place
over the nail head. Photo: Jeffrey S. Levine.
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Replacing an entire roof feature such as a cupolaor
dormer when repair of the historic materials and limited
replacement of deteriorated or missing parts are appropriate.
Failing to reuse intact slate or tile when only the
roofing substrate needs replacement.
Using a substitute material for the replacement part
that does not convey the visual appearance of the surviving
parts of the roof or that is physically or chemically
incompatible.
Replace
Replacing in kind an entire feature of the roof that
is too deteriorated to repair--if the overall form and
detailing are still evident--using the physicalevidence
as a model to reproduce the feature. Examples can include
a large section of roofing, or a dormer or chimney.
If using the same kind of material is not technically
or economically feasible, then a compatible substitute
material may be considered.
Removing a feature of the roof that is unrepairable,
such as a chimney or dormer, and not replacing it; or
replacing it with a new feature that does not convey
the same visual appearance
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Asphalt shingles are an incompatible replacement
substitute for the original Spanish clay tiles.
Photo: NPS files.
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The following work
is highlighted to indicate that it represents
the particularly complex technical or design aspects
of Rehabilitation projects and should only be
considered after the preservation concerns listed
above have been addressed.
Design for the Replacement of Missing Historic
Features
Designing and constructing a new feature when
the historic feature is completely missing, such
as chimney or cupola. It may be an accurate restoration
using historical, pictorial, and physical documentation;
or be a new design that is compatible with the
size, scale, material, and color of the historic
building.
Creating a false historical appearance because
the replaced feature is based on insufficient
historical, pictorial, and physical documentation.
Introducing a new roof feature that is incompatible
in size, scale, material and color.
The following work is
highlighted to indicate that it represents the
particularly complex technical or design aspects
of Rehabilitation projects and should only be
considered after the preservation concerns listed
above have been addressed.
Alterations/Additions for the New Use
Installing mechanical and service equipment on
the roof such as air conditioning, transformers,
or solar collectors when required for the new
use so that they are inconspicuous from the public
right-of-way and do not damage or obscure character-defining
features.
Designing additions to roofs such as residential,
office, or storage spaces; elevator housing; decks
and terraces; or dormers or skylights when required
by the new use so that they are inconspicuous
from the public right-of-way and do not damage
or obscure character-defining features.
Installing mechanical or service equipment so
that it damages or obscures character-defining
features; or is conspicuous from the public right-of-way.
Radically changing a character-defining roof
shape or damaging or destroying character-defining
roofing material as a result of incompatible design
or improper installation techniques.
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