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Historic Preservation - Technical Procedures
Guidelines For Rehabilitating Historic Buildings: Roofs
National Park Service, Preservation Assistance Division
Guidelines For Rehabilitating Historic Buildings: Roofs
GUIDELINES FOR REHABILITATING HISTORIC BUILDINGS: ROOFS
U.S. Department of the Interior
National Park Service
Preservation Assistance Division
An illustrated booklet addressing the Secretary's Standards and the
guidelines is available from the U.S. Government Printing Office.
The title is "The Secretary of the Interior's Standards for
Rehabilitation & Illustrated Guidelines for Rehabilitating Historic
Buildings", ISBN 0-16-035979-1.
Each of the guidelines included in the booklet mentioned above have
been separated into individual entries for specific use in HBPP.
This entry represents one of many guidelines included in the
booklet and describes RECOMMENDED and NOT RECOMMENDED applications
of the Secretary of the Interior's Standards as they relate to
Roofs. For a list of the Secretary of the Interior's Standards for
Rehabilitation, see 01091-04-S; For general information relating to
the purpose, organization and content of the individual guidelines,
see 01091-05-S. Both of these entries should be referenced along
with the information contained in this document.
The roof -- with its shape; features such as cresting, dormers,
cupolas, and chimneys; and the size, color, and patterning of the
roofing material -- can be extremely important in defining the
building's overall historic character. In addition to the design
role it plays, a weathertight roof is essential to the preservation
of the entire structure; thus, protecting and repairing the roof as
a "cover" is a critical aspect of every rehabilitation project.
IDENTIFYING, RETAINING AND PRESERVING
- 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.
- 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
- 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"
- 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.
PROTECTING AND MAINTAINING
- 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 insure that materials are free from insect
- 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
- Providing adequate anchorage for roofing material to
guard against wind damage and moisture penetration.
- Allowing roof fasteners, such as mails and clips to
corrode so that roofing material is subject to
- Protecting a leaking roof with plywood and building paper
until it can be properly repaired.
- Permitting a leaking roof to remain unprotected so that
accelerated deterioration of historic building materials
-- masonry, wood, plaster, paint and structural members
- Repairing a roof by reinforcing the historic materials
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.
- Replacing an entire roof feature such as a cupola or
dormer when repair of the historic materials and limited
replacement of deteriorated or missing parts are
- 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
- Replacing in kind an entire feature of the roof that is
too deteriorated to repair -- if the overall form and
detailing are still evidence -- using the physical
evidence to guide the new work. 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.
NOTE: THE FOLLOWING REPRESENTS PARTICULARLY COMPLEX TECHNICAL OR
DESIGN ASPECTS OF REHABILITATION PROJECTS AND SHOULD ONLY BE
CONSIDERED AFTER THE PRESERVATION CONCERNS LISTED ABOVE HAVE BEEN
DESIGN FOR MISSING HISTORIC FEATURES
- Designing and constructing a new feature when the
historic feature is completely missing, such as a 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
replace feature is based on insufficient historical,
pictorial, and physical documentation.
- Introducing a new roof feature that is incompatible in
size, scale, material, and color.
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.
- Installing mechanical or service equipment so that it
damages or obscures character-defining features; or is
conspicuous from the public right-of-way.
- 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.
- Radically changing a character-defining roof shape or
damaging or destroying character-defining roofing
material as a result of incompatible design or improper
END OF SECTION