Preservation - Trost Society

Why Preservation?

Historic buildings and properties are the real places that tell the real stories of Texas. They bring the diversity of Texas’ rich history to life and enhance the distinctive character of every town and community. The Texas Historical Commission works to identify, preserve, and protect historic properties across the state. On this page, learn the answers to some basic questions about historic buildings and properties.

What is a historic property?

Historic properties are buildings, structures, objects, sites, or districts with historical or archeological significance. This includes a wide range of resources, from building to bridges, acequias, trains, rock carvings, battlefields, and cultural landscapes. In order to better understand the range of resources that fit into these categories, please see Guidelines for Local Surveys: A Basis for Preservation Planning (National Register Bulletin #24).

To be considered “historic,” a property must possess three essential attributes: it must have sufficient age, a relatively high degree of physical integrity, and historical significance:


A property’s significance must be evaluated based on historical perspective. Generally, a property must be at least 50 years old to be considered historic. This “50-year rule” exists because it is rarely possible to evaluate historical impact, role, or relative value immediately after an event occurs or a building is constructed — the passage of time is necessary to apply the adjective “historic” and to ensure adequate perspective. That said, properties with clear exceptional significance can be recognized as historic before they are 50 years old. One such example is the Apollo Mission Control Center at Johnson Space Center, which was designated a National Historic Landmark before reaching 50 years of age for its exceptional importance in the manned spacecraft program of the United States.


A property must have integrity to be considered historic. This means that the property must retain the physical characteristics that existed during its period of significance. It is a given that historic properties change over time, and changes made to continue a property’s function during its career may even acquire significance in their own right. The National Park Service recognizes a property’s integrity through seven aspects: location, design, setting, materials, workmanship, feeling, and association, all of which combine to convey a property’s significance.


A property must have significance at the local, state, or national level to be considered historic. While the specific criteria vary between designation types, generally a property must be significant in prehistory or history, whether for its association with important events or persons, for its architecture or design, or for its potential to yield archeological information.

What properties are considered historic?

State and Federal Historic Designations

Many historic properties have already been identified across the state of Texas. There are several established ways in Texas of publicly determining whether properties are historic and worthy of being preserved. Historic Designations in Texas gives a summary of federal and state-level designations and the protections they afford to historic properties. Preservation covenants and easements can also be used to protect significant historic properties.

The Texas Historical Commission maintains the Texas Historic Sites Atlas, which features nearly 300,000 site records on historic properties throughout the state. Properties with Recorded Texas Historic Landmark or subject markers, properties listed in the National Register of Historic Places, courthouses, and State Antiquities Landmark buildings (not archeological sites) can all be found on the Atlas.

Local Designations

Properties may also receive designations through a local government or municipality. Local governments can pass ordinances that specify standards and procedures for designating historic properties, with their own criteria and designations. Often this is accomplished through the participation in Texas Historical Commission’s Certified Local Government program, which is designed to help cities and counties develop high standards of preservation to protect a wide range of important historic properties.

Historic Resources Survey

Identification of historic properties is the first step towards designation and preservation. The Texas Historical Commission’s Historic Resources Survey program maintains files of existing surveys and encourages new survey activity statewide.

Section 106 Reviews

The National Historic Preservation Act of 1966 requires that federal agencies consult with the Texas Historical Commission prior to undertaking projects that may impact historic resources in Texas. An important step of this process is the identification of historic properties in the area that may be affected by a project. This consultation process, referred to as a Section 106 review, identifies a significant number of historic properties each year in Texas.

What guides work to historic properties?

Standards and Guidelines

When it comes to doing work to a historic property, the Texas Historical Commission — along with other local, state, and national preservation organizations — utilizes the Secretary of the Interior’s Standards for the Treatment of Historic Properties as their guidelines. The Texas Historical Commission can provide technical assistance and guidance to owners of historic properties, regardless of whether their building officially designated, to ensure that work to a building will not result in a loss of integrity.

Building Codes

The purpose of all building codes is to provide minimum requirements for new and renovated buildings in order to protect the health, safety, and welfare of the public. Some building codes have sections that specifically reference and allow greater flexibility for work to historic buildings that provides an equivalent level of safety.

Providing Access to Historic Properties

The Americans with Disabilities Act, Texas Architectural Barriers Act, and Texas Accessibility Standards promote the elimination of unnecessary barriers encountered by persons with disabilities. Historic buildings and sites are not exempt from compliance but may qualify for variances.

Historic Preservation and Sustainability

Most historic buildings are, due to their materials, design and context, inherently efficient. Historic preservation projects can incorporate sustainable design to conserve materials and energy while prolonging the life of existing buildings. Energy efficiency benchmarks may be mandated by local code requirements, or sustainability measures may be voluntarily pursued.

Project Review

Texas Historical Commission review may be required in some cases before work to a historic building or property may proceed. Staff conducts project reviews as required by state and federal laws, historical designations, and other legal protections for historic properties. These include:

The Texas Historical Commission also reviews applications for the federal rehabilitation tax credit program.

CREDIT: Text courtesy of Texas Historical Commission

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