Considerations when specifying Cylinder or Crown glass for period and listed properties
For many protected buildings (listed and conservation), council planners require 3mm ‘Crown reproduction’ glass to be used, either as single glazed or incorporated into a slimline double glazed unit.
One of the main restrictions of this, is that 3mm Crown glass cannot be toughened which can affect many windows and doors inside a property.
A 5mm Crown reproduction glass is available that can be toughened and can be incorporated into a Timbalite slim double glazed unit.
Where safety is concerned, all windows and doors for listed buildings do need to confirm to Part N (now known as Part K) for building regulations, unlike Part L which talks about the thermal requirements which are exempt for protected buildings.