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The Standards are neither technical nor prescriptive,
but are intended to promote responsible preservation
practices that help protect our Nation's irreplaceable
cultural resources. For example, they cannot,
in and of themselves, be used to make essential
decisions about which features of the historic
building should be saved and which can be changed.
But once a treatment is selected, the Standards
provide philosophical consistency to the work. The four treatment approaches are Preservation, Rehabilitation, Restoration, and Reconstruction, outlined below in hierarchical order and explained:
The first treatment, Preservation, places a high premium on the retention of all
historic fabric through conservation, maintenance and repair. It reflects a building's
continuum over time, through successive occupancies, and the respectful changes and
alterations that are made.
Rehabilitation, the second treatment, emphasizes the retention and repair of historic
materials, but more latitude is provided for replacement because it is assumed the
property is more deteriorated prior to work. (Both Preservation and Rehabilitation
standards focus attention on the preservation of those materials, features, finishes,
spaces, and spatial relationships that, together, give a property its historic character.)
Restoration, the third treatment, focuses on the retention of materials from the most
significant time in a property's history, while permitting the removal of materials from
other periods.
Reconstruction, the fourth treatment, establishes limited opportunities to re-create a
non-surviving site, landscape, building, structure, or object in all new materials.
Choosing the most appropriate treatment for a
building requires careful decision-making about
a building's historical significance, as well
taking into account a number of other considerations:
Relative importance in history. Is the
building a nationally significant resource--a
rare survivor or the work of a master architect
or craftsman? Did an important event take place
in it? National Historic Landmarks, designated
for their "exceptional significance in American
history," or many buildings individually listed
in the National Register often warrant Preservation
or Restoration. Buildings that contribute to the
significance of a historic district but are not
individually listed in the National Register more
frequently undergo Rehabilitation for a compatible
new use.
Physical condition. What is the existing
condition--or degree of material integrity--of
the building prior to work? Has the original form
survived largely intact or has it been altered
over time? Are the alterations an important part
of the building's history? Preservation may be
appropriate if distinctive materials, features,
and spaces are essentially intact and convey the
building's historical significance. If the building
requires more extensive repair and replacement,
or if alterations or additions are necessary for
a new use, then Rehabilitation is probably the
most appropriate treatment. These key questions
play major roles in determining what treatment
is selected.
Proposed use. An essential, practical
question to ask is: Will the building be used
as it was historically or will it be given a new
use? Many historic buildings can be adapted for
new uses without seriously damaging their historic
character; special-use properties such as grain
silos, forts, ice houses, or windmills may be
extremely difficult to adapt to new uses without
major intervention and a resulting loss of historic
character and even integrity.
Mandated code requirements. Regardless
of the treatment, code requirements will need
to be taken into consideration. But if hastily
or poorly designed, a series of code-required
actions may jeopardize a building's materials
as well as its historic character. Thus, if a
building needs to be seismically upgraded, modifications
to the historic appearance should be minimal.
Abatement of lead paint and asbestos within historic
buildings requires particular care if important
historic finishes are not to be adversely affected.
Finally, alterations and new construction needed
to meet accessibility requirements under the Americans
with Disabilities Act of 1990 should be designed
to minimize material loss and visual change to
a historic building.
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