How to Repair Transom Windows

December 15, 2015

Transom windows have been utilized in home design for several hundred years. In early designs, the main purpose of the windows was to allow additional light into a room as well as providing ventilation. More recently, transom windows have been incorporated into architectural designs more-so for their aesthetic value. Whether you live in an older home, or something more modern, at some point you may be forced to repair or replace the transom windows in your home.

The first thing you need to do is to determine if your transom window is one solid piece of glass or if it is made up of several smaller individual panes. If you get up close and look at the sectional dividers (muntins) you should be able to see if the glass is one continuous piece or not.

Repairing One Piece Transom Windows

If the transom glass above your door or window is one continuous piece you will need to change out the entire assembly. In most cases this is a matter of removing the exterior trim surrounding the transom assembly. Use a sharp utility knife to cut through the paint and caulking so you can see where the trim and the frame meet. Use a small pry-bar to remove the trim, being careful not to damage the trim so it can be reused.

Once the trim is removed you can gently pry the transom window assembly out of the framework. Carefully measure the exterior dimensions of the transom frame so you can purchase a replacement that will easily slide into place. Once the new window is in place you can reinstall the trim. Use new finishing nails to secure the trim.

Repairing an Individual Transom Window Pane

In many older homes, the transom windows are individual panes of glass. In this case, gently remove the glazing around the single broken window pane. If the glass has multiple cracks, you may want to cover the entire pane in masking tape to keep the pieces together for safety. Once removed, accurately measure the glass so you can order a replacement from your local window repair shop. With the new pane in place you can re-glaze the window.

Finishing Touches

In both cases you need to re-caulk the perimeter of the transom window to seal and protect the wood beneath. Allow the caulking and/or glazing to fully cure before applying a fresh coat of quality exterior paint and primer.

Contact Us:

Have more questions about replacing or repairing the transom windows in your home? Contact One Source Renovation, LLC at or give us a call at (815)-634-8922.