Most existing sashes and casements can have their glazing rebates deepened to accept our ultra slim double glazed sealed units. Where it is not possible to re-cut the existing sashes, then we manufacture new Hardwood sashes and casements to copy the existing but with double glazing and fitted to your existing sash boxes or frames. This is usually also much less costly than replacing the complete window and one is retaining much of the original ‘antique’ and avoiding much of the disruption to internal decoration normally associated with a complete window replacement.