Developments in Historic Glazing

Historic Glazing can be a contentious issue in the restoration and renovation of properties that are listed or located in a conservation area. Conservation Officers will favour repair over replacement to protect the authenticity of the original single glazing. Replacement, on the other hand, is often the preferred option for homeowners and developers to improve the property’s energy and acoustic efficiency.

Slim Insulated Glazing Units

Developments in slim insulated glazing units (IGUs), also commonly referred to as narrow cavity glazing, have helped in finding a balance between sympathetic restoration and achieving improved levels of performance. However, a number of window manufacturers have voiced concerns over the quality of some slim IGUs, leading to guidance being issued by the BWF (British Woodworking Federation) and the GGF (The Glass and Glazing Federation).

Having supplied historic glazing to some high-end developments, including the refurbishment of the Chanel New Bond Street Store, we have published this blog to provide guidance when specifying slims IGUs.

Guidance in Specifying Slim IGUs

It is crucial to check that the manufacturer who is supplying historic windows fitted with a slim IGU can provide test evidence to ensure that the glazing units will not be subject to premature loss of performance or failure.

Things to check for include:

  • That the glazing unit is CE marked;
  • The manufacturer can provide a Declaration of Performance to support the glazing unit;
  • That the glazing unit meets the requirements for the durability of glass units given in the BS EN 1279 series of standards for Glass in Buildings.

At George Barnsdale we place great emphasis on the following test data from the manufacturers whom we source slim IGUs from:

  • EN 1279-2, moisture penetration;
  • EN 1279-3, gas leakage;
  • EN 1279-4, edge seal strength.

For more information on our Historic Range of timber windows and doors for replacement in listed or conservation properties, please visit the Historic Range product page.

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