Throughout Britain and Ireland, casement windows were common before the
sash window was introduced. They were usually metal with
leaded glass, which refers to glass panes held in place with strips of lead called
cames (leaded glass should not be confused with
lead glass, which refers to the manufacture of the glass itself). These casement windows usually were hinged on the side, and opened inward. By the start of the Victorian era, opening casements and frames were constructed from timber in their entirety. The windows were covered by functional exterior shutters, which opened outward. Variants of casement windows are the norm in many European countries. They are sometimes opened with a
crank,
lever, or
cam handle, which is placed around hand height or at the bottom and serves as a window lock.{{cite book Often, the glass panes are set in a
rabbeted frame and sealed with
beveled
putty or
glazing compound to secure the glass. The hinging of casement windows is referred to using the following abbreviations:
FCL refers to a left-handed window, where the hinges are located on the left and the locking mechanism is on the right.
FCR is a right-handed window with the hinges on the right and the locking mechanism on the left. These definitions apply to a window when looking at it from the exterior ("from curb" or FC). In some countries
architectural diagrams of casement windows show a dashed triangle with the hinged side identified by the point of the triangle (e.g. USA), while in others they point to the lever, showing a simplified perspective of the opened window (e.g. Hungary, Germany). Furthermore, in some countries (e.g. Hungary, Germany) diagrams also make distinction between windows opening inwards (dashed line) or outwards (solid line). FCL windows feature a triangle pointing to the left; FCR windows have a triangle pointing to the right. ==Energy efficiency and natural ventilation==