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Category: Masterframe


Lightweight, 1/8th glass (3mm) meant the lower rail of the upper sash in Georgian properties could be slender, normally 1 ½” (38mm). Victorians later thickened up this section so that heavier plate glass could be supported and added sash horns to prevent mortice and tennon joints opening.
Using modern materials we’ve now created an opportunity to have the same slender, elegant Georgian proportions yet carry the vastly heavier glass weights that today’s energy efficient sash windows demand.
Our Bygone Symphony range has this ultra slim lower rail as standard and it is an optional upgrade on Bygone Harmony. Being just 39mm it is by far, the slimmest sash rail of any of our products or any PVC sash window on the market.
PVCu is a soft material which has the tendency to sag with the weight of glass and deflect with wind pressure, very easily, that’s why they should always be reinforced with galvanised steel sections. The new meeting rail however is an incredible 19 times stronger than the existing slim meeting rail (52mm) and nearly 5 times stronger than our large sash (62mm). In fact the new slender bar is so much stronger that there is virtually no maximum width of window, the only governing parameter will be the sash weight for balances.
With the new slender bar, comes more daylight. More solar gain means an even higher Window Energy Rating.