How to Repair Bay Windows

October 10, 2010

Bay windows, when properly installed and insulated, can last for years without much maintenance. But bay windows, because they are so large, can have problems that other windows flush with the walls do not have. Two common bay window problems are sagging and rotting wood.

Find Window Experts Fast

How soon do you want to begin this project?

How to Repair Bay Windows with Sagging Problems

These windows, because of their sheer size and weight, can sometimes sag, making it impossible to open the windows. To get bay windows back into place, use two hydraulic jacks in each corner of the window. Lift slowly to avoid any stress on the window.

Make sure you support the jacks on planks (2 x 8s are fine), so the jacks don't shift or sink into the ground. Perform the process slowly until the window is about one-eighth inch above your desired window height. You will then want to support the window from the top with a few structural metal brackets (wood is also okay to use). Once the brackets are secured, carefully lower the jacks.

Rotting Wood on Frame, Sashes

If only a small area has rotted, you can usually repair it using a fiber glass repair kit from your hardware store. You can also fix the crack or hole with small wood pieces. However, if you have extensive rotting in your bay windows, you will probably have to replace the wood. There also may be hidden rotten wood if you have vinyl or aluminum cladding. The tell-tale signs of this problem include:

  • Casement window screws are loose
  • Sashes don't close properly
  • Mushy spots in the window

Larger rotting problems may require the help of a window expert, unless you are previously well-experienced in how to repair bay windows.


To find a door or window expert now,
call toll-free: 1-866-969-5157