Glazing for Historic Buildings

IQ Glass can offer slim double glazed units which serve as brilliant replacement units for historic and conservation properties greatly increasing their thermal and efficiency performance.

Replacing single glazing with thermally efficient double glazed units heralds a myriad of issues, from planning officers to installation challenges; standard, cheap UPVC replacements have the tendency to leak and creak equating to a waste of investment in the thermal efficacy of a home or space.

IQ's Slim Glazing Units are double glazed glass units with a unit thickness of only 10-12mm. Using this system we are able to effectively and invisibly upgrade thermally inefficient, old and cracked single glazed units with a double glazed system achieving u-values which far more than adhere to Building Regulations thermal efficiency targets.

The glass panels consist of two panes of 4mm glass, the inner pane applied with low-e coatings to increase thermal efficiency, an inert gas filling and warm edge spacer technology. The gas used in these units is generally a mixture of Krypton and Xenon. These gases are heavier than the standard Argon gas filling, which is used in most double glazed units, and are perfect for this small cavity opening. The heavier gas along, with the small cavity spacer, means that no convention currents can form in the internal gas filling and cavity, meaning less heat loss to the external faces.

Steel Framed Windows for Historic Buildings
steel framed windows and doors for historical buildings

Design Integrity

The glass units look like single glazing from any distance, thus not changing the outward appearance of an old or listed property. But using this glazing solution gives you U Values from as little as 1.2 W/m2K compared with the typical 5.4 W/m2K in a single glass panel.

To put it into some kind of context; the replacement of 1m2 of single glazing with a low-e double glazed unit will save 90kg of CO2 emissions per year, saving money and cutting down on heat loss.

In other technical aspects of the glass, the normal noise reduction (or the RW value) is 31dB with light transmission at 72%.

These slim units are extremely suitable for replacing glass in traditional Georgian sash windows, able to fit into a rebate of only 7mm, and have been acclaimed by Kevin McCloud for their ability to both thermally enhance historic buildings whilst keeping the design integrity of the original structure in place.

Where truly historic glass is required, IQ can offer modern sealed units laminated to reclaimed or new cast or cylinder glass.

Robbie Cox
Contracts Manager
IQ Glass UKIQ Glass UKIQ Glass UK

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