What is a casement window?

The different types of casement window

• Side hung

  The most common type of casement window that is hinged at the side and the window opener will swing outwards.

• Single casement

  A basic window that has just one panel and is usually side hung.

• Double frame or french casement

  Two panel windows that are both side hung. The window has a central mullion with the window handles in the centre and opens outwards to create a large aperture opening.

• Top hung or awning window

  A window that opens from the bottom and is hinged at the top. The window swings outwards so rain doesn’t come into the room in wet climates.

• Bottom hung or hopper window

  The window opens at the top of the frame with a hinge at the bottom - tilt and turn use a bottom hinge. Ideal for apartments and upper floor rooms to allow safe opening.

• Flush casement

  A sleek frame where the window sits flush in the frame when closed. A contemporary finish that is becoming more popular, especially for aluminium frames that have a slim profile.

• Fixed casement

  A casement window that doesn’t open. Usually part of a configuration that has window openers on either side. Popular in bay windows.

1. Window Frame
   The window frame holds the casement window in place. It is made up of a head and a sill that runs horizontally along the top and bottom, combined with two jambs that run vertically on either side.
2. Window Sill
   Forming the bottom of the window frame, window sills (also called cills) are slanted to effectively direct water away from the window frame and the building.
3. Casement
   The casement is the part of the window that opens, securing the glazing in place.
4. Mullion
   A window mullion is the vertical strip of supporting uPVC, timber or aluminium that divides separate window units.
5. Transom
   A window transom is the horizontal strip of supporting uPVC, timber or aluminium that divides separate window units.
6. Lock Handle
   The casement window's locking mechanism is located on the casement jamb.
7. Trickle Vent
   Fitted at the top of the window, trickle vents consist of a grill on the outside and a closing vent on the inside.
8. Georgian Bars
   Fitted inside the sealed unit, Georgian bars are the vertical and horizontal bars that create the classic appearance of the glass being divided up into small squares.
9. Astragal Bars
   Similar to Georgian bars, Astragal bars are applied to one single piece of glazing; fitted on top of the window, internally and externally.