Wood windows have evolved over time from simple coverings for holes in exterior house walls to more complex enclosure systems. Each wood window is comprised of various components. Each component serves a purpose within the window.
The sash is the frame that surrounds the glass pane. The exterior window frame surrounds the group of sashes for each window. Fit the sash to the pane using custom measurements for each glass piece. Bind the sash together around the pane using joints, glue or nails. Install muntins to separate the glass panes when using a double pane window. Customary wood windows have two sashes making up the top and bottom of the window.
Rails and stiles are parts of the sash. Rails are the top and bottom edges of a sash; stiles are the sides of the sash. Attach the ropes, weights and pulleys to the rails; attach the locks and pull handles to the stiles. The rail that is made up of where two sashes meet is called the check rail.
Panes are the glass contained within the window. Each pane fits into a single sash. There can be any number of panes within a window depending on the size of the window.
The frame is the exterior wood holding the remaining components together. Set the functional parts, such as the rope, weights and locks on the frame. Attach the window to the building using the frame. The frame is comprised of the jamb – the four sides of the window frame; and the sill – the horizontal piece placed below the bottom jamb.
Trim is what surrounds the window frame once the window is in place. The trim covers the gaps around the window frame and the wall opening. The trim installed at the base of the window is called the apron. Install insulation around the window between the wall and the window frame before applying the trim around the window.