Anatomy

Describing the various parts of a sash window often leads to confusion and misunderstanding, so we have included an illustration of a sash window below to see the labelled parts, click on the window below and then roll over the ‘hot-spots’ to see the names of the parts.

The word “sash” is believed to derive from the French word “chassis”, meaning “frames”. To add to the confusion, different parts of the erstwhile British Empire (USA, Ireland, Canada), used various names for what we usually call here in Ireland “sash windows”.

They are also called:

  • “double hung windows” (independent counter-weight for both sashes)
  • “box frame” windows” (a box required on each side to house the weights)
  • “sliding sash windows”
  • “guillotine windows” (French influence from the 1790s, most likely!)
  • “up-down sliding windows”
  • “vertical sliding windows”

All the above names describe the same basic window design, which achieved its highest technical development in the early years of the eighteenth century. This window design remained the industry standard, until steel windows became more popular in the 1930’s.

The number of glass panes in each sash was governed by the technology of the time. In early Georgian times (early 1700s) panes could not be made much bigger than approx. 10” x 16” so, large “sash” windows typically had to have six glass panes in each sash. An arrangement of nine panes over six or nine was not unusual in very large windows. As glass production technology improved, larger and larger panes could be produced, so that, by Victorian times, one could have as few as two panes per sash, and that was considered to be very posh. By Edwardian times, after the turn of the twentieth century it became possible to have just one pane over one; that was considered to be even more posh, as this glass was very expensive. Very often the front windows would be one pane over one, while the back of the house had windows with 2 panes over 2, to cut down the cost.

See design styles page for further details about window and glazing bar design. Call us on 01 213 0213, email us  or contact us for  further information.