Three Types of Extruded Windows: Bay, Bow, and Box

December 16, 2009

Ever wonder what the differences and similarities are among these three types of windows that extend beyond the exterior walls? Read on to find out.

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Bay Windows

Bay windows are composed of three or more panels that are at 30 degree or better angles to each other. The usual arrangement of a bay window is a center panel that is parallel with the wall with a flanking window on either side. Some or all of the windows may open.

Bay windows are often associated with Victorian style homes, especially those in San Francisco, although they are not restricted to use in that architecture. The original glass in some bay windows built in the mid 19th century was curved. If you are replacing curved glass and are determined to maintain authenticity, be prepared to have the window custom made.

Bay windows take their name from the fact that they form a bay, not because they face the San Francisco Bay (since there are bay windows in houses in just about every state).

Bow Windows

Bow windows are composed of four or more panels and are set at 10 degree angels to each other forming a bow shape (as in a drawn archery bow). As is the case with bay windows, some or all of the panes may open.

Sometimes the interior floor follows the extension of the window beyond the exterior wall. This arrangement is called a "bump out." Otherwise, the window is considered a standard bow or bay.

Both bow and bay windows may extend from ceiling to floor, but often they are designed with a window seat to encourage enjoyment of the view.

Box windows

Box windows have panels that are set at right angles to each other forming a three-sided box. These windows usually have a stationary center pane since the depth of the box prevents easy opening of the center window.

Box windows are designed to not so much to take advantage of a view as to provide space and light for growing plants. The top of the box is usually glass whereas the tops of bay and bow windows are often metal, or have covers that match the outside roofing material.

All three types of extruded windows usually require building permits. There may be weight or weather conditions that will determine the maximum size or shape of your installation. Egress from a room is also a major consideration. Work with your contractor or window supplier to determine the right configuration of window for your plans.


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