2020-3-10 Att3 - Guidelines for Zoning-MA-Donohue (1).doc

GSA New England Region 1

Harold D. Donohue FB

Building Preservation Plan March 10, 2020 Attachment 3 – Guidelines for Zoning Historic Buildings

Attachment 3: GUIDANCE for ZONING HISTORIC BUILDINGS I.

BACKGROUND

Zones are GSA’s response to the need for guidance for accommodating new requirements and tenant needs while preserving a building’s historic character. Zoning aids GSA in planning major and minor repairs, alterations, and maintenance through a hierarchy of significance that categorizes exterior and interior areas and spaces.

The BPP uses a three-zone system of treatment categories to reflect the relative architectural importance, visibility, and integrity of the building’s exterior and interior spaces.

“Restoration” zones are significant spaces worthy of restoration.

“Rehabilitation” zones are spaces of secondary significance containing historic materials that should be preserved during rehabilitation efforts.

“Renovation” zones are spaces of little or no significance, or that have been extensively altered, that are able to accommodate substantial alteration without compromising the overall integrity of the historic property.

II.

GUIDANCE

A. Understanding Building Evolution Zoning requires research on the building’s evolution, to identify significant spaces that may be compromised by alterations, and onsite inspection, to document current conditions and develop recommendations for the short and long term care of the building. An important GSA goal is maintaining continuity in the character and quality of each building’s public spaces. Consideration is given to how the original designers intended visitors and occupants to experience the building, focusing on the experience from the entrance, through lobbies, along corridors and up stairways or elevators, to the visitor or occupant’s destination.

B. Assessing Spaces

Zoning should consider that spaces are seen and experienced three dimensionally as volumes, not surfaces. Accordingly, zones should encompass a volume and field of vision, typically a 360 degree view, for enclosed spaces, or a 180-270 degree view for partially enclosed spaces or exterior areas. Facades encompass visible roofing and adjoining grounds and streetscape features. Flat or very shallow pitched roof areas not visible as part of a facade may be zoned separately with recommendations providing guidance on the appropriate placement of building equipment, utilities, penthouse structures, and other alterations to avoid adversely affecting restoration or rehabilitation zoned facades.

C. Suggested Workflow

1. Review original and current floor plans, elevations, and photographs of the building to understand the historic and evolving spatial hierarchy, sequence, and flow.

2. Using information on the building’s design, construction, function, and evolution, identify space types based on function and visibility, keeping in mind related functions may be vertical as well as horizontal.

3. Compare the location, spatial volumes, and richness and relative quality of architectural finishes and details within and among the major functional divisions.

4. Identify and delineate contiguous areas in the building where there is a consistent level of detail, quality, and richness of elements and finishes.

5. Document conditions or anomalies worth noting either for their contribution to the building’s historic character, or as intrusions that detract from the building’s integrity.

6. Assign tentative zone levels of restoration, rehabilitation, or renovation.

7. Walk through the building, progressing from exterior to interior, lower levels to upper levels, to confirm or adjust zone assessments.

III. ZONE DEFINITIONS

The Building Preservation Plan’s three-zone system of treatment reflects the relative architectural importance, visibility, and integrity of the building’s exterior and interior spaces. At the end of the zoning process, the site, all facades, and all interior spaces shall have been assigned one of the three zoning designations. Zone assignments provide recommended treatments and are not intended to be binding.

A. Zone 1 - Restoration Zone Restoration zones are significant spaces worthy of preservation (if intact) and restoration (if not). Typically, they include primary facades and their settings, landscaped courtyards, public lobbies, principal/ceremonial corridors, open stairways, original elevators containing original finishes, courtrooms, hearing rooms, other ceremonial spaces, libraries, and executive suites.

These spaces are usually distinguished by the richness or quality of their architectural finishes, detailing, and spatial attributes, e.g., high ceilings, compared to the other spaces. These architecturally significant spaces merit retention (preservation) of their original features, as well as restoration to remove inappropriate alterations and reinstall missing features important to their historic character. In historic modern era buildings, restoration zone spaces may be identified by finish materials such as polished stone or bush-hammered concrete; generous spatial volumes compared to other spaces in the building; contoured or pyramidal surfaces; and/or custom-fabricated, architecturally integrated lighting or indirect lighting that highlights distinctive architectural surfaces and features.

Many spaces will have been altered to some degree over time because they remain in active use. Alterations do not preclude zoning an otherwise significant space as a restoration zone, as long as the space remains essentially intact and can be restored without extensive reconstruction.

To justify restoration in GSA project planning and budgeting, these primary spaces must be designated restoration zones. A building’s BPP recommendation narrative should explain priority restoration goals such as removal of inappropriate alterations within the building’s principal entrance lobby, courtrooms, and primary ceremonial corridors. Recommendations for restoration of modern interiors containing finish materials intended to be periodically replaced should include guidance for appropriate replacement consistent with the original design intent.

B. Zone 2 - Rehabilitation Zone Rehabilitation zones are spaces of secondary significance that contain historic materials or features worthy of preservation. Examples include intact secondary corridors, standard offices containing historic materials, and toilet rooms retaining original finishes and features such as marble or structural glass partitions. Rehabilitation zones may also include tenant spaces where alterations have occurred but significant original materials remain, e.g., windows, trim, doors, or plaster walls. To justify preserving a historic corridor’s overall configuration and character-defining historic materials, while allowing flexibility to accommodate contemporary workspace layouts, the corridor should be designated a rehabilitation zone. Rehabilitation goals, e.g., to increase spatial openness or introduce transparency for improved office daylighting, may be discussed in the “Recommended Treatment” section.

C. Zone 3 - Renovation Zone Renovation zones typically include spaces that do not contribute to the significance of a building, such as attics, basements, utilitarian office space, and areas which have been so altered that little or no original material remains. In modern era buildings, renovation zones may encompass large portions of an interior, as spaces in this era were typically intended to be altered as needed to meet changing needs.

Renovation zone spaces may be demolished in their entirety, as long as the alterations do not adversely affect adjoining rehabilitation or restoration zone spaces. Alterations to ceilings, walls, doors, and other features adjoining rehabilitation or restoration zones must be undertaken in a manner that preserves the appearance and integrity of adjoining significant spaces. For example, configuring suspended ceilings to preserve the full height of windows as seen from the outside of the building preserves the character of the exterior restoration zone facades.

IV.

SPECIAL SITUATIONS

A. Circulation Spaces In determining whether circulation spaces should be designated a restoration or rehabilitation zone, consideration should be given to relative architectural significance and integrity, compared to other public spaces and circulation spaces;

importance of the circulation path component as part of the originally intended public or ceremonial pathway into and through the building; and anticipated changes that will be required to maintain the building’s functionality or viability.

Circulation spaces linking primary entrance lobbies and other public spaces such as auditoriums, courtrooms, hearing rooms, and libraries are more likely to merit restoration zoning as a reflection of architectural merit and importance in the building’s ceremonial pathway. Less distinguished secondary corridors, particularly ends of corridors where flexible space planning can be accommodated without disrupting the continuity of circulation between ceremonial spaces, may be designated rehabilitation zones. Recommendations for retaining a reading of the corridor within planned open space, e.g., by retaining flooring, ceiling, or wall portions, may be included in the “Recommended Treatment” section, where appropriate, to guide anticipated alterations.

B. Contiguous Spaces Contiguous spaces, such as those designed as components of a suite, should typically be placed within one zone to maintain their character as an integrally designed spatial unit. Restoration zones containing courtrooms, historic executive suites, and ornamental meeting rooms should normally include associated ancillary spaces and the corridors connecting them, if these spaces remain intact and integral as part of a spatial continuum or suite.

V.

DOCUMENT and PLAN PREPARATION A. Zone Explanatory Text The zone explanation text at Section III, above, shall be included in the BPP text under “Building Evaluation and Analysis.”

B. Computer Aided Drafting

Zone plans and elevations will be produced using Computer Aided Drafting (CAD), with the Contracting Officer's Representative to determine the specific application and version of CAD required for this contract.