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Double Glazing Knowledge

Box Sash Windows

Box sash is the style of window that dates back to the 1600’s. Normally two sash panels when either could slide up an down, held on ropes over a pulley and sometimes linked so they open in tandem. Whilst the fenestration has changed throughout the Georgian, Victiorian, and Edwardian periods (as glass making improved) the mechanicals haven’t, a sash window open at the top and bottom is still the most efficient style of window for ventilation.

Known today as sliding sash or vertical sliders, they are generally more expensive than casements. Metal springs (called balances) have replaced the ropes and pulleys because two sheets of glass make sashes extremely heavy, but they still look fabulous, and many local conservation areas are now insisting sash windows get replaced with sash windows.

High end sash window companies now make windows that are “virtually identical” to timber originals.

Tip, if security if an issue, then ensure windows are BS5750 approved, this is the standard the police look for to get their “Secured by Design” accreditation (SBD)