Specialist heritage glazing & slim sealed units
6mm Argon Cavity•14mm Nominal

4mm Low-E Float / 6mm Argon cavity / 4mm Activ Toughened

Request made-to-measure heritage double glazing combining 4mm Low-E Float on the inside, a 6mm Argon gas cavity and 4mm Activ Toughened as Panel 2. This separate 14mm nominal sealed-unit make-up is available to discuss with a specialist supplier.

Interactive Cross-Section

Exploded Sealed Unit Architecture

Inside Pane4mm Low-E (Annealed)
Cavity & Gas6mm Argon
Outside Pane4mm Activ Toughened (TGH)
Nominal Depth14mm (±1mm)
Sightline Flange: 7mm
Spacer Finish: Warm-Edge (Black)
Secondary Seal: Polymer Heritage Butyl
Sightline is perimeter seal depth into rebate. Cavity is noble gas gap. Gas does not recolour glass.

Activ toughened glass for heritage glazing

Request a heritage sealed unit with a 4mm Activ toughened second pane. Include the window position and any safety-glazing requirements so the supplier can confirm the specified Activ glass, toughened treatment and complete unit construction for your project.

For this 4mm Activ Toughened product, the selected 6mm cavity and Argon gas give an indicative U-value baseline of 2.0 W/m²K. Panel 1 is 4mm Low-E Float; Panel 2 is 4mm Activ Toughened. The total nominal unit thickness is 14mm. Confirm your rebate depth, sightline, spacer colour and the declared thermal performance with the supplier before ordering.

Choosing 4mm Activ Toughened for heritage double glazing does not establish planning or conservation permission. Your supplier should confirm the exact product, and any required appearance match or project approval must be checked separately.

Technical Specification

Inside Pane:4mm Low-E Float
Cavity & Gas:6mm with Argon
Outside Pane:4mm Activ Toughened
Nominal Thickness:14mm (±1mm)
Indicative U-Value:2.0 W/m²K — indicative baseline; confirm with supplier