With the frame in place, the window sash is then installed. The sash, which holds the glass panes, is carefully attached to the frame using the pre - installed hinges. The hinges are adjusted to ensure that the sash opens and closes smoothly and that it aligns properly with the frame when closed.

The hardware, including locks, handles, and the crank mechanism for manual - opening windows, is then installed. Locks are an important safety feature, and they are installed to ensure that the window can be securely closed. Handles are attached for ease of operation, and the crank mechanism is connected to the opening system of the window sash. For automated windows, the motors or actuators are installed and connected to the control system, which may include wiring and a power source.

 Sealing and Finishing

Once the window sash and hardware are installed, sealing is a crucial step. A weatherproof sealant is applied around the perimeter of the window frame, both on the interior and exterior sides. This sealant creates a barrier against water, air, and dust, preventing them from entering the building through the gaps around the window.

On the exterior, flashing may be installed to further enhance the water - resistance of the window. Flashing is typically made of metal and is placed above and around the window to divert water away from the wall. Interior trim, such as moldings or casings, can be installed to cover the gaps between the window frame and the wall and to give the window a finished look. Finally, the window is thoroughly inspected to ensure that all components are installed correctly and that the window operates smoothly.