BY WILLIAM BRACKEN, PE, FRSE, SI
On Jan. 26, 2026, the Florida Building Commission, the Florida Department of Business and Professional Regulation, and the Building Officials Association of Florida issued a Florida Building Code binding interpretation (report number 318) regarding the replacement of windows and doors in Threshold Buildings.
The interpretation was issued in response to a petitioner’s question.
Is replacement of windows considered a modification to the building’s structural system and therefore required to meet the requirements of Section 110.8.1 of the Florida Building Code, Building, 8th Edition (2023)?
The three organizations responded with the following answer:
The answer to the Petitioner’s question is yes. The replacement of windows constitutes a modification of the building’s structural system. Accordingly, this work is required to comply with Section 110.8.1 of the Florida Building Code, Building, 8th Edition (2023).
Simply put, windows and doors are critical components of the building’s envelope, and while not part of the Main Wind Force Resisting System (MWFRS), they are component and cladding elements that receive and transmit wind loads to the MWFRS. Therefore, window and door replacements are considered a modification to the building’s structural system and as such are required to comply with the Florida Building Code, Building, Section 110.8.1 Threshold Buildings.
Section, 553.71, Florida Statutes: A Threshold Building is any building greater than three stories or 50 feet in height, or which has an assembly occupancy classification that exceeds 5,000 square feet in area and an occupant content of greater than 500 persons.
Section 110.8.1 of the Florida Building Code, Building, pertains to any project involving the modification of a Threshold Building’s structural system or structural loading, whether it’s new construction or work on an existing building. In short, it requires that a structural inspection plan be submitted at the time of permitting and that the corresponding inspections be performed by a Special Inspector. It also states that the purpose of the structural inspection plan is to provide specific inspection procedures and schedules so that the building can be adequately inspected for compliance with the permitted documents. The structural inspection plan is to be prepared by the engineer or architect of record and submitted to the enforcing agency prior to the issuance of a building permit.
Therefore, Florida licensed engineers who also hold either a Special Inspectors certification or a Special Inspector (Limited) certification will be able to perform Threshold Inspections of the replacement of windows and doors on existing Threshold Buildings.
Special Inspector (Limited) – Professional engineers offering threshold building inspection services for Threshold Buildings with Repair (without Substantial Structural Damage), Alterations 1, Alterations 2, and Alterations 3 (without Substantial Structural Alterations) of existing threshold buildings shall be certified by the Board to be a Special Inspector (Limited) under the qualifications set forth in Rule 61G15-35.0021(2), F.A.C.
Whereas, the installation of windows and doors in new construction, along with the entire range of services required of Special Inspectors, will require a Florida licensed engineer who is certified by the Board to be a Special Inspector under the qualifications set forth in Rule 61G15-35.003, F.A.C.
As stated within the interpretation, it is binding and not subject to acceptance and approval by the local building official. To research this or any other binding interpretation, please use the Florida Building Commission’s binding interpretation search. For more on the Florida Building Commission or the code development process, please visit the Florida Building Commission’s website.
Mr. Bracken’s career has spanned nearly four decades and has centered on the practice of civil/structural engineering while specializing in its application in the fields of Design, Construction, Building Codes, and Standards of Care. He has served as the vice-chair and chair of the Florida Board of Professional Engineers, as an Urban Search & Rescue Structural Specialist, and currently works as a Technical Trainer for the International Code Council. Mr. Bracken is a recognized Fellow within the Structural Engineering Institute (SEI), the American Society of Civil Engineers (ASCE), and is a Board-Certified Diplomate and Fellow of the National Academe of Forensic Engineers (NAFE).