Alterations to Historic Resources

Applications to alter designated historic resources (excluding demolition) are reviewed in accordance with Implementing Zoning Ordinance Section 15.050 and 15.070. Review under those sections includes an evaluation of conformance with district guidelines (when applicable) and the Secretory of Interior’s Standards for the Treatment of Historic Properties.

The review of all proposed alterations begins with gaining an understanding of the historic features of the property. Prior surveys may have documented those features but, frequently, a qualified professional is needed to conduct research and prepare a Historic Resource Evaluation if one has not previously prepared. Please see the information below pertaining to the required qualifications and ways to locate a qualified professional.

Once you have gained an understanding of historic features and composed plans for alterations in conformance with applicable guidelines and standards, a Historic Site Plan and Architectural Review application is filed. Links to required application forms are provided below. Depending upon the nature and extent of alterations proposed, application are considered and acted upon by either Planning Division staff or the Historic and Cultural Preservation Committee.


Demolition Policy

The review of applications for demolition permits is considered under Implementing Zoning Ordinance Section 15.060 and City Council Resolution No. 2017-122 N.C.S. (‘Demo Policy’). The basic purpose of each is to address concern over the incremental loss of the historic building stock. The proposed demolition of any structure built before 1945 is subject to review. Demolition is defined as,

“Demolition means the removal of 50% or more of the exterior walls of a building or structure. Demolition may also include the addition of a second story if not appropriately designed and differentiated from the original structure to convey its history as determined by the Planning Manager. Demolition also includes the relocation of a building from one parcel of land to another or the raising of an existing structure beyond what is required for construction of a new foundation.

The removal and replacement in kind of deteriorated, non-repairable material required for the restoration or rehabilitation of a building which results in no change to its exterior appearance or character is not considered a demolition. The initial determination of whether a project meets the above description of demolition shall be made by the Planning Manager or their designee. Any dispute over whether a project meets this definition will be decided by the Historic and Cultural Preservation Committee.”

Depending upon the historic significance of the building in question, applications for demolition permits are evaluated as part of the Building Permit process, an Administrative Site Plan and Architectural Review application, or Major Site Plan and Architectural Review application. Please contact Planning Division staff for guidance on the appropriate review process and necessary supporting evidence.


How to Find a Qualified Professional

The Northwest Information Center (NWIC), associated with Sonoma State University and the State Office of Historic Preservation, maintains a list of Historic Resources Consultants who have documented that they meet one or more of the following professional categories identified in the Secretary of the Interior’s Standards for the Treatment of Historic Properties:

  • Archaeology
  • Architectural History
  • Architecture
  • Historic Architecture
  • History


To search for Historic Resources Consultants qualified to prepare Historical Surveys and Evaluations who work in or near Sonoma County, visit the California Historical


Resources Information System website and:
1. Select “Architectural History”, “Historic Architecture”, or “Architecture” under “Select a Discipline”
2. Select “Sonoma” under “Select a County”
3. And press “Search

Questions regarding the List of Historic Resources Consultants may be directed to the Northwest Information Center at (707) 588-8455 or [email protected].
Property owners may also contact Petaluma Planning Division staff for a list of qualified professionals who have prepared Historic Surveys or Evaluations for review in the recent past.


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