What Is a Flush Fin Window?

What Is a Flush Fin Window?

A flush fin window, also called a flange, z-bar, or jump frame window, is designed to replace the window in an existing home. Flush fin windows are easier to install than many other types of windows and they're a great replacement option for stucco homes. Here’s some more information about flush fin windows and the things you should know before installing windows in stucco walls.

What Is a Flush Fin Window?

A flush fin replacement window sits within an existing window frame, and it has an exterior fin that covers the old frame and sits on top of the home’s siding or stucco. Flush fin windows can be wood, vinyl, or aluminum. The fins can make them look more prominent from the outside than many other types of windows, and flush fin windows look like any other window type from the inside of a room as long as they are properly trimmed. They really a type of insert window because they are placed in/over existing window frames.

Milgard's Z-Bar window frame is an example of a flush fin window. Most companies call them flush fin windows or stucco frame windows.

Things You Should Know About Installing Windows in Stucco Walls

Flush fin windows are an ideal option for stucco homes, and they can help you take care of the unique challenges that replacing windows on a stucco house present. Here are some things you should know about installing windows in stucco:

Stucco Isn’t Waterproof

Stucco is a very durable material that resembles plaster, but it’s not waterproof. Stucco homes usually have a layer of flashing or building paper between interior and exterior walls to prevent leaks. While people call this material paper, it’s usually made from plastic and fiberglass insulation.

Damaging this material by replacing an entire window frame could make leaks more likely. To remove the frame, a professional will need to smash holes in the stucco around it. This could create cracks in your stucco that might lead to mold or mildew, and you’ll need to have the opening waterproofed before you add a new window. After you replace the window and repair the stucco, the exterior walls of your home could look patchy, discolored, or uneven.

Removing It Could Be Hazardous

The stucco↗ in many older homes contains asbestos, and it can lead to lung damage if you breathe in dust that contains it. If you choose not to use a flush fin window, you’ll need to wear protective equipment while you remove the window frame.

Flush fin windows are the easiest option when replacing windows in stucco homes, and they’re available in many colors, styles, and insulation levels. Contact us at Brennan Enterprises for installation help from one of our experienced professionals.


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