How to Repair Circle-Top Windows

Also called radius windows, circle-top windows have spindles radiating from the bottom center of a circle top window. This structure requires replacing one or more glass panes within a circle top window.

How to Repair Circle-Top Windows: What to Know

Repairing a circle top window requires multiple considerations:

• Replacement cost: Circle top windows are expensive, and generally cost from $400 to $1,000 or more depending on size and structural complexity and glazing.
• Availability: Circle-top windows are often sold as part of a window package that includes the bottom window. Finding a single circle-top window may require purchasing it through a firm specializing in architectural renovation and reproductions, or directly from a window manufacturer. This can lead to shipping and "guesstimating" how a replacement circle top window will fit over the main window below. Ordering parts or a replacement window from the original manufacturer is your best option for finding a proper match to the lower window.
• Architectural and historical integrity: Consulting a windows contractor experienced in historical and architectural window repair and renovation is important. Original circle-top windows may contain lead or other materials not allowed under current building codes. Your windows contractor can help find safe alternatives that maintain your home's appearance while meeting building codes. Specialty glass suppliers can help with locating reproduction glass appropriate for your project.
• Glazing: When replacing a single panel of a circle-top window, finding glass to match the rest of the window can be difficult if your circle-top window contains stained and/or textured glass. Having the entire window re-glazed may be necessary for matching glass panels within your circle-top window.

Repairing a circle-top window yourself may be possible if you're skilled in glazing techniques; how to repair circle-top windows depends on window structure, age, and materials.