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Notation: Space

Definition

"The contribution which related places and related objects make to the cultural significance of the place should be retained."

Article 11, Australia ICOMOS Burra Charter, 1999, Australia ICOMOS

Interior sections or area of classified by one or more systems including: historical significance, use, accessibility, circulation, codes, security, environment — and other criteria.

References

Preservation Note 28: Building Zones, Special Procedures-01350, 01-General Requirements, Historic Preservation Note Series (displays all notes, equal to 134 pages of text; a large file), Historic Preservation Technical Procedures, Historic Buildings Program, U.S. General Service Administration, January 1999.

The General Services Administration's (GSA) historic buildings must provide functional office space for federal tenants. Changes in the work place demand certain alterations in historic buildings, such as the increased electrical need by computers. In order to preserve the most important and historic spaces, alterations should occur in areas with minimal architectural or historical significance.

A majority of the National Capital Region's (NCR) historic buildings have been surveyed to assist in locating areas that can be altered. The Historic Structure Reports are the surveys that provide assistance, usually as Chapter 9, Design Guidelines/Rehabilitation Guidelines.

IntroductionCriteria for New Accommodations and InstallationsCriteria for Modification or Adaptation of Existing Features

Introduction

Original finish materials and architectural features of special significance can and should be preserved. Rehabilitation projects should be designed and implemented so that no irreparable changes or alterations will be made, and installation of new materials will not harm those materials and features. Because changed programmatic factors make restoration of all areas unfeasible, buildings are divided into three zones which designate a recommended level of intervention:

Restoration (Zone 1): areas of high architectural and/or historical significance should be restored to their appearance at the time of initial fit-out. "Restoration is the process of accurately recovering, by removal of later work and the replacement of missing original work, the form and details of a structure or part of a structure, together with its setting, as it appeared at a particular time."

  • Zone 1 areas occupy a significant portion of the building, and, with few exceptions, are used by all occupants and most visitors. Should future intervention be required in restoration zones, the intrusive quality of projects, such as installation of mechanical and electrical systems and barrier-free access ramps, should result in little or no visible impact through careful coordination of new work with existing architectural features and finishes. Where repair or restoration of existing features is required, that work should conform to current technical standards.

Rehabilitation (Zone 2): areas of moderate architectural and/or historical significance containing significant architectural details which should be preserved or restored as part of any repair or alteration project. Defined by the Secretary of the Interior's Standards, Rehabilitation is "the process of returning a property to a state of utility, through repair or alteration. Rehabilitation makes possible an efficient contemporary use while preserving those portions and features of the property which are significant to its historical, architectural, and cultural values." (While the Standards advocates in-kind-replacement of missing, or deteriorated historic fabric, that approach is typically implemented on a "where prudent and feasible" basis.)

  • Zone 2 areas occupy the largest portion of the building, and are used by all occupants and most visitors. Retention, preservation, and exposure of significant details in those areas in conjunction with compatible alterations can preserve the overall continuity of the building. Use of contemporary design elements compatible with recommendations contained in The Secretary of the Interior's Standards for Rehabilitation and Guidelines for Rehabilitating Historic Buildings, as well as restoration and preservation of significant details will reveal the additive nature of alterations to the building over time.
  • Because extensive future intervention will most likely be required in Zone 2 areas, the potentially intrusive nature of projects, such as installation of electrical and mechanical systems, should be carefully controlled. This goal can be achieved by careful coordination of new work and existing architectural features and finishes and the use of contemporary design elements intended to be readily distinguishable from and deferential to historic building fabric. Where repair or preservation of existing features is required, that work should conform to current technical standards.

Renovation (Zone 3): areas of minimal architectural or historical significance and containing no significant architectural details which should be preserved or restored as part of any overall repair or alteration project. "Repairs involve the replacement of deteriorated materials which it is impractical to save such as broken window glass, severely rotted wood, etc. Repair activities also include the rehabilitation, strengthening or reclamation of items worn to the point that they can no longer perform their intended function. In historic buildings, stock used for repairs should be as close as possible to the original in composition of materials, in methods of fabrication and in manner of erection." Repairs and/or alterations in Zone 3 areas should not adversely affect restoration and/or rehabilitation zones.

  • Zone 3 areas occupy the smallest portion of the building and are used by few occupants or visitors. Since those areas are not and will not be publicly accessible, and because significant architectural details tend not to be located in those areas, retention, preservation, and exposure of such features is of minimal importance. Use of contemporary design elements compatible with recommendations contained in The Secretary of the Interior's Standards for Rehabilitation and Guidelines for Rehabilitating Historic Buildings is recommended as a means of preserving the overall continuity of those areas of the building. Although substantial redesign of these areas is acceptable, alterations should temper the intrusive quality of projects such as installation of mechanical and electrical systems through careful coordination of new work with existing architectural features and finishes to the greatest extent feasible. Where repair or preservation of existing features is required, that work should conform to current technical standards.

Criteria for New Accommodations and Installations

Architectural character reflects the building's underlying structure and original program as well as its appearance. Preservation of significant portions of those aspects of its past and present can complement and strengthen that character. Because the impact of preservation goes well beyond the return of missing or damaged artifacts to their original appearance, factors such as the relationship between new alterations and existing historic fabric must be carefully considered. A successful resolution of that relationship is the essence of rehabilitation, and a compatible relationship between rehabilitation and preservation need not be limited to concealing new alterations or presenting them in a mode derived from historical forms.

New alterations involving rehabilitation of existing mechanical, electrical, plumbing, and security systems and introduction of additional life safety compliance measures can be expected. When concealing new alterations is impossible, the Secretary of the Interior's Standards should be used. The following excerpts give some guidance for new alterations.

The Secretary of the Interior's Standards [for Rehabilitation] discuss introduction of new materials.

Standard (9) requires that

. . . new work shall be compatible with the massing, size, scale, and architectural features [of the historic property] to protect the historic integrity of the property and its environment.

Additionally, Standard (10) states that

New additions and adjacent or related new construction shall be undertaken in a manner that if removed in the future, the essential form and integrity of the historic property and its environment would be unimpaired.

The recommended approach for necessary alterations, that cannot be concealed, advocates the development and implementation of an architectural vocabulary that would allow new work to meet the following criteria in regard to existing historic fabric:

  • result in minimal change,
  • be visually and physically compatible, and
  • be reversible without causing excessive damage.

Criteria for Modification or Adaptation of Existing Features

Restoration Zone (Zone 1)

Recommendation: Restore to appearance at the time of initial fit-out.

Zone 1 areas include the most architecturally and/or historically significant and publicly accessible portions of the building. When required, modification or adaptation of existing features to accommodate new alterations should be accomplished by methods involving the least possible amount of disruption to existing historic building fabric. Recommended approaches to this goal include the following:

  1. Location of new work within existing voids. This approach would render new work invisible by virtue of its concealment within existing spaces such as chases, ducts, closets, and radiator enclosures. It would require no removal or alteration of historic building fabric. The approach would be limiting in certain instances because installations of new work would be restricted to vertical runs, many of which are of shallow depth. Use of the approach would be limited to a fairly small range of alterations whose components are of relatively modest size such as those associated with some mechanical, electrical, plumbing, communications, and security systems.
  2. Location of new work within newly formed voids. This approach would also render new work invisible by concealment within newly formed spaces hollowed-out from existing building fabric such as masonry walls and floors, and plaster and hollow-metal partitions. Although similar in effect to the approach described above, it would require removal or alteration of historic fabric of limited visibility. The approach would be advantageous in certain instances because installation of new work need not be restricted to vertical runs. Because the amount of fabric that could be removed would be relatively small, use of the approach would be also be limited to a fairly small range of alterations whose components are of relatively modest size such as those associated with mechanical, electrical, plumbing, communications, and security systems.

Rehabilitation Zone (Zone 2)

Recommendation: Retain, preserve, and expose significant details in Zone 2 areas in conjunction with introduction of alterations compatible with recommendations contained in The Secretary of the Interior's Standards for Rehabilitation and Guidelines for Rehabilitating Historic Buildings as a means of preserving the overall continuity of the building. While restoration of all rehabilitation zones is not recommended, restoration of selected rehabilitation zones such as corridors or certain offices is warranted to permit the full context of the building to be accurately represented.

Zone 2 areas include the most intensely used portions of the building. Although most are of secondary architectural and/or historical significance, their central role within the overall concept of the building makes them appropriate for preservation and exposure of significant details in conjunction with compatible alterations. Where restoration of these spaces is not required, modification or adaptation of existing features to accommodate new alterations should be accomplished by methods involving the least possible amount of disruption to historic fabric. Recommended approaches to this goal can but need not include those advocated for Zone 1 areas as well as the following:

  1. Exposure of new work. This approach would not attempt to render all new work invisible by concealing it within existing or newly formed voids. Instead, exposure of appropriately designed and clearly distinguishable alterations would be acceptable. Those alterations could range from creation of new partitions and chases to outright exposure of equipment. Allowable limits for removal or alteration of historic building fabric would be clearly defined in all cases. Use of the approach can apply to a broad range of alterations such as those associated with mechanical, electrical, communications, lighting, and security systems.

Renovation Zone (Zone 3)

Recommendation: Use contemporary design elements in zone 3 areas which are compatible with recommendations contained in The Secretary of the Interior's Standards for Rehabilitation and Guidelines for Rehabilitating Historic Buildings as a means of preserving the overall continuity of the building. Restoration of Zone 3 areas is neither required nor recommended.

Zones 3 areas comprise the "back room" portions of the building. These areas are historically inaccessible to the public and most users, and continue to remain so. Significant architectural details were not found in these areas, and exposure of such details, where they occur, is of limited importance. Recommended approaches to these spaces can, but need not, include those advocated for Zone 2 areas.

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