We can manufacture sash and case windows to suit any thickness of double glazed unit. Generally speaking a thickness of 18mm is considered to be about the maximum allowed before the unit starts to look different to a traditional sash and case window.
Exceeding this thickness of glass may often clash with local legislation and building controls. In listed buildings and conservation areas a slimline unit is usually required. Its thickness is usually around 14mm, 4/6/4, argon filled, low e glass unit. For no additional cost we will fit toughened glass to the lower sash for reasons of safety.
Double glazing is obviously much heavier than single glazing. For that reason we will manufacture our units with haunched tenons and usually with an ornate horned detail. This is not just for aesthetic appearance but also because it helps to strengthen the upper sash.
Double glazed units look very similar to their single glazed cousins and this means that the general look of your property will be altered very little.