In the early 18th century Georgian style sash windows had small panes because of the limits of the glass manufacture. What is more, in each sash you could find as much as sixteen small panes. But as the period developed, the number of the panes in a Georgian sash window reduced to six for each sash by creating „six over six“ pane style. Also, because of the bigger availability of cheaper softwoods from Baltic states and Scandinavia, the width of the glazing bars began to decrease. By the end of the eighteenth century, timber glazing bars in Georgian sash windows were as little as ten millimeters wide.
The sliding sashes were balanced with lead weights so that they could give a smooth operation. The weights were enclosed in timber enclosures to the side of the panes.