South Florida is home to numerous historically significant neighborhoods and individually designated historic properties, from the Art Deco district of Miami Beach to the historic homes of Old Fort Lauderdale and the pioneer-era residences in West Palm Beach. Owners of these properties face a unique challenge when it comes to hurricane protection: they need the life-safety benefits and insurance advantages of impact windows, but they must also preserve the historic character and architectural integrity that gives their property its special significance. Navigating the intersection of historic preservation requirements and modern building code mandates requires careful planning, the right products, and experience working within the guidelines established by local historic preservation boards.
Historic preservation guidelines typically address the appearance of windows from the exterior, including the window style, proportions, profile dimensions, color, and the overall visual character of the window within the facade. The Secretary of the Interior's Standards for Rehabilitation, which most local historic preservation programs follow, generally require that replacement windows match the appearance of the original windows as closely as possible. This means that the replacement impact windows should replicate the original window's configuration, such as the number and arrangement of panes, the sightlines and profile widths of the frame and sash, and the material appearance. Many impact window manufacturers now offer product lines specifically designed for historic applications, featuring narrower frame profiles, simulated divided lite configurations with between-the-glass or applied muntin bars, and traditional styling details that closely replicate the appearance of historic wood windows while providing full impact certification.
The approval process for replacing windows in a designated historic property typically involves submitting an application to the local historic preservation board or architectural review committee before beginning work. This application usually requires detailed information about the existing windows, the proposed replacement windows including manufacturer specifications and profile drawings, and photographs showing the current condition. Some boards require physical samples of the proposed windows. The review process evaluates whether the proposed replacement windows meet the applicable preservation guidelines for the property or district, and the board may approve the application as submitted, require modifications, or in some cases deny the application if the proposed windows are deemed incompatible with the historic character. Working with a contractor who has experience with historic preservation projects can significantly smooth this process, as we know what information the boards require, what products are most likely to receive approval, and how to present applications that address the board's preservation concerns.
One approach that some historic property owners use is to install impact windows that exactly match the exterior appearance of the original windows while providing modern performance on the interior side. This can include impact windows with wood or wood-look exterior cladding that matches the original material appearance, or aluminum windows with custom color-matched finishes that replicate the look of painted wood. For properties where the original windows had true divided lites with individual small panes, impact window manufacturers can create simulated divided lite configurations with applied exterior and interior muntin bars combined with a spacer bar between the glass layers, creating a convincing illusion of individual panes while maintaining the structural integrity of a single laminated glass panel. The cost of these specialized historic impact window products is typically higher than standard impact windows due to the custom profiles, finishes, and configurations required, but the investment preserves the historic value of the property while providing the hurricane protection and insurance benefits that every South Florida homeowner needs. We have completed impact window projects on several designated historic properties in South Florida and understand the sensitivity and precision these projects require.