Codes and Regulatory Requirements for Rehabilitating Historic Buildings

Rehabilitating historic buildings involves compliance with building codes that establish minimum levels of safety and performance, including accessibility, fire and life-safety, mitigation of hazardous materials, seismic upgrades, energy performance, and other requirements. Code adoption varies by jurisdiction, so it is not possible to address every code and code requirement in depth, but National Park Service (NPS) publications such as Preservation Brief 51: Building Codes for Historic and Existing Buildings: Planning and Maximizing their Application (2024) and other NPS guidance are intended to assist building owners and design professionals in better understanding code requirements as they relate to historic buildings. Consultation with code officials, State Historic Preservation Offices (SHPOs), and the NPS in the early stages of the planning process can also help ensure that historic rehabilitation projects satisfy applicable code requirements while still meeting the Secretary of the Interior’s Standards for Rehabilitation and preserving a property’s historic character.

The purpose of NPS guidance and information on this topic is to provide a broad overview of code and regulatory requirements as they impact historic buildings and to acknowledge the complexities of accommodating them in a manner that is sensitive to the historic building and that preserves its character. The section on code-required work in the Secretary of the Interior’s Standards for the Treatment of Historic Properties with Guidelines for Preserving, Rehabilitating, Restoring & Reconstructing Historic Buildings was revised and expanded in 2017, including added sections on code-required work as part of the other three sets of treatment guidelines in addition to the Rehabilitation Guidelines.

Other NPS publications provide more specific guidance on accommodating these regulatory requirements in rehabilitation projects:

• Preservation Brief 32: Making Historic Properties Accessible
• Preservation Brief 41: The Seismic Rehabilitation of Historic Buildings
• Preservation Brief 51: Building Codes for Historic and Existing Buildings: Planning and Maximizing their Application

Meeting code requirements while still preserving historic buildings and their character-defining features, spaces, and materials as much as possible is essential for their long-term preservation and viability. Historic buildings must be adapted to meet current performance requirements for accessibility, fire and structural safety, and energy conservation, as well as emerging requirements addressing protection from natural disasters and climate change.

Accessibility and the Americans with Disabilities Act (ADA)

The NPS was instrumental in implementing the Americans with Disabilities Act (ADA) in 1990 and worked with numerous public and private partners to make these requirements sympathetic to historic buildings while still meeting accessibility requirements. Historic buildings can incorporate upgrades and other changes to make them more accessible and in way that is compatible with their historic character and consistent with the Standards.

In addition to the 2017 Treatment Guidelines, Preservation Brief 32: Making Historic Properties Accessible provides more detailed information and examples on this topic.

Fire and Life-Safety

The NPS was involved in the development by the International Code Council (ICC) of the International Existing Building Code (IEBC) and continues to participate in model code development as a member of the ICC. In contrast to earlier codes written primarily for new construction, the International Existing Building Code (IEBC) model code, adopted in 2003, acknowledges the unique construction and circumstances of historic buildings and includes specific provisions to address them.

Many jurisdictions have since adopted the IEBC which provides several paths for complying with the code requirements, including the Performance Compliance Method which evaluates each building on its individual characteristics. This allows greater cost savings and further protection of historic resources. In addition, many states and jurisdictions adopt their own codes, sub-codes, or amendments to the IEBC that are specific to historic buildings. Greater flexibility, cost savings, and protection of historic resources can be experienced in states with such codes.

In addition to the 2017 Treatment Guidelines, Preservation Brief 51: Building Codes for Historic and Existing Buildings: Planning and Maximizing their Application provides more detailed information and examples on this topic.

Hazardous Materials

Hazardous materials present in historic buildings generally require some level of mitigation. This mitigation must meet applicable environmental codes, and it should minimize the impact on the building’s historic integrity while still protecting the health and safety of occupants. Asbestos, asbestos-containing materials, and PCBs in fluorescent light fixtures are some of the materials routinely remediated as part of historic rehabilitation projects.

One of the most prevalent hazardous substances is lead-based paint. The U.S. Department of Housing and Urban Development (HUD), Office of Lead Hazard Control and Healthy Homes has provided guidance on different approaches from “abatement” to “interim controls,” encouraging practices that are less costly than previous treatments and more sensitive to historic resources. “Interim controls” are treatments lasting at least six years and are generally tied to proper maintenance and good hygiene. The most common “interim control” is paint stabilization in areas of friction and high impact. In other instances, abatement may be the preferred method of remediation.

The 2017 Treatment Guidelines and Preservation Brief 51: Building Codes for Historic and Existing Buildings: Planning and Maximizing their Application provide additional general guidance. Preservation Brief 37: Appropriate Methods of Reducing Lead-Paint Hazards in Historic Housing is currently under revision, but HUD has published guidance on Lead-Based Paint and Historic Buildings and has other resources available to assist property owners.

Seismic Retrofit

Depending on where in the United States a building is located, rehabilitations of historic buildings may require adding seismic reinforcement to structural and non-structural components to meet codes. Assembling an experienced professional team and early identification of the seismic risk factors of a historic building are very important in implementing a successful seismic retrofit plan.

Prescriptive code requirements can often result in excessive removal of historic materials or significant alterations to the historic character of a building. However, with careful planning it is possible to introduce new structural reinforcement in a manner that minimizes alteration or removal of spaces, features, and finishes that give a building its unique historic character while still meeting code requirements. Recognizing those features that are important in defining the historic character of a building is essential in order to determine what means and methods are best suited for a successful seismic retrofit plan.

In addition to the 2017 Treatment Guidelines, Preservation Brief 41: The Seismic Rehabilitation of Historic Buildings provides more detailed information and examples on this topic.

2007; rev. July 2024