Types of glazing

Glazing for heritage properties

The original glass in many period sash windows and casement windows, called crown glass, would have been hand-made and has a unique uneven reflection (see above right) that is vital to preserving the character of period, conservation and listed properties. Unfortunately over the years much of this beautiful, historic glass has been replaced with modern ‘float’ glass (above left), which has a completely different look and devalues the character of historic properties.

Modern production techniques have meant that glass looks a lot flatter than it used to when it was made for windows in the Victorian and Georgian eras and earlier. Modern double glazing can also change (and ruin!) the look of a period property.

Thankfully there are ways to replicate the traditional look of glass for period windows – and even include subtle, slimline double glazing – which can maximise energy efficiency and comfort without compromising the authentic look of the property.

Restoration glass & slimline double glazing

At Timbawood, we have a range of bespoke glazing options which have been accepted for windows and doors on listed and conservation properties by planning authorities throughout London and the South East.

Our restoration glass, or replica crown glass, has the slightly uneven look of the original machine-drawn or hand-drawn period glass, in contrast to the flat look of modern float glass. This is ideal for listed buildings and conservation properties to give an authentic ‘wobbly’ reflection and preserve the look of the property.

We also offer slimline double glazing, which looks just like single glazing and can have a gap between the panes of glass of just 4mm, and total unit thickness of 11mm, for heritage properties. The outer pane of glass can be glazed with restoration glass, as well as other bespoke options including acoustic glass for additional noise insulation and laminated security glass.

As specialists in bespoke timber windows and doors for period, conservation and listed properties, we create elegant, exact-match period windows and doors that are authentic to the original character of a property, while improving security and insulation performance. 

Energy efficient glazing

There are a number of ways we can improve the energy efficiency of our slimline double glazing, achieving U values of as low as 1.2 W/m2K for thermal efficiency, depending on the gas fill used. We use particularly dense, inert gases such as krypton and xenon, which are poor conductors of heat. We use a softcoat 1.1 ‘Low E’ pane for the inner pane of glass, which reflects heat back into the building. And our warm edge spacer bars, which separate the two panes of glass, are more thermally efficient than the traditional aluminium.

If you are looking for timber windows and/or doors for period, conservation and listed properties, at Timbawood we offer a complete, bespoke service from design, manufacture to installation, offering full replacement windows and doors as well as sensitive restoration work on conservation and listed buildings. Please get in touch if you would like advice from one of our experts or a quote for your project.

Our range of glazing options include:

  • Laminated security glass
  • Acoustic glass
  • Restoration glass
  • Slimline double glazing
  • Patterned and opaque glass