Our single glazed double-hung traditional timber box sash windows are manufactured using through mortise and tenon construction, with weight and pulley counter-balance system as standard and solid through glazing bars.

These bespoke copies of original Georgian windows incorporate hand-blown cylinder glass where required. A standard single-glazed box sash window will incorporate either 4mm float glass or 3mm hand-blown cylinder glass, all finished externally with linseed oil putty and fitted with draught proofing.

A commonly held assumption is that local planning authorities will not approve double glazing in grade II listed properties. Our double glazed box sash windows have previously been approved in grade II listed projects by multiple local planning authorities across the UK, including Westminster, South Shropshire and Herefordshire.


Examples of single glazed box sash windows in a variety of period properties. In keeping with the character of these period buildings, 
most of these replacement windows are glazed with hand-blown
cylinder glass and finished with linseed oil putty