A window jamb is a vertical structural component forming the side of a window opening. This element provides support for the window sash and is essential for the secure and proper operation of the window. They are the flat, vertical boards that line each side of the window opening, running from the sill at the bottom to the head jamb at the top.
The structural integrity of the window relies heavily on these side pieces. They ensure the window remains square and prevents drafts by creating a tight seal when the window is closed. Historically, well-crafted side elements were key to a building’s energy efficiency and overall durability, playing a role in preventing water infiltration and maintaining a comfortable indoor climate.