Tel: 0208 893 4420
Fax: 0208 867 2767
Email: info@timbalite.com


Tel: 0800 043 1054
Fax: 0208 867 2767
Email: info@timbalite.com

Listed Building Double Glazing Units


Glazing for Period and Conservation Area Properties

Timbalite conservation glazing units are manufactured using a combination of the very highest specification materials available.

As standard, our slimline glazing units include Softcoat 1.1 glass as its Low E pane, which is more thermally efficient than traditional hardcoated glass, such as K glass, and it also does not carry the same amount of colour.

Timbalite softcoated slimline units

Unit ThicknessConfigurationCentre Pane UV W/m2KSightline (+1mm tolerance)
11mm4mm Softcoat 1.1 / 4mm Krypton filled cavity / 3mm Clear1.9 W/m2K7mm
12mm4mm Softcoat 1.1 / 4mm Krypton filled cavity / 4mm Clear1.9 W/m2K7mm
14mm4mm Softcoat 1.1 / 6mm Krypton filled cavity / 4mm Clear1.4 W/m2K8mm
16mm4mm Softcoat 1.1 / 8mm Krypton filled cavity / 4mm Clear1.2 W/m2K9-10mm
12mm4mm Softcoat 1.1 / 4mm Xenon filled cavity / 4mm Clear1.5 W/m2K7mm
14mm4mm Softcoat 1.1 / 6mm Xenon filled cavity / 4mm Clear1.2 W/m2K8mm

All centre pane U values are based upon calculations by Buildcheck Oracle (UKAS Certified)

With Timbalite conservation glazing units being available with either a 4mm or 6mm cavity, they are available from only 11mm thick with a perimeter seal width of from only 7mm.

This enables period property homeowners to benefit enormously from energy efficient, listed building double glazing, whilst replicating the original design of their listed windows, including the narrow glazing bars so important to maintaining a truly authentic appearance.

Example of conservation glazing detail:
12mm Timbalite slimline glazing unit

Sightline / Seal Depth

11mm / 12mm unit with 4mm cavity: 7mm sightline (+1mm tolerance)
13mm / 14mm unit with 6mm cavity: 8mm sightline (+1mm tolerance)

Units can be installed to both new and restored traditional listed windows and doors with putty line detailing to match the existing.

These high performance conservation glazing units are produced using the latest technology warm edge spacer bars in a choice of colours, ensuring they are as thermally efficient as possible and can produce centre pane U values of 1.9 or 1.5 Wm2K on a 4mm gas filled cavity, to as low as 1.4 or 1.2 Wm2K on a 6mm gas filled cavity, depending upon the type of gas fill used.


  • minimum 8.5mm rebate depth
  • minimum 20mm rebate width

All Timbalite listed building double glazing units carry a 5 year guarantee and can be delivered nationwide in a specialized packaging, ensuring they get to you in a perfect condition.