What is Secondary Glazing and how can it help?

Roads, railways, airports and even people all contribute to noisy environments in every day life.


Fitting Secondary Glazing to your existing window surrounds can significantly reduce the amount of external noise helping to create a more comfortable living / working environment.


In addition, Secondary Glazing can also vastly reduce the amount of heat lost through draughty windows. This reduction can be further enhanced by fitting energy efficient glass such as Pilkington K Glass™

Why Fit Secondary Glazing?


Scenarios where Secondary Glazing may be used as an alternative to full window replacement include:

  • Any area where excessive external noise can affect the environment around you. i.e. major roads, airports and train lines even through modern double glazing.
  • Properties within conservation areas or listed buildings where the external character of the property must not be affected by fitting replacement PVCu or aluminium windows.
  • When a low cost alternative to complete replacement double glazing is required due to budget constraints but a high quality solution is needed.
  • An easy, quick and effective method for improving traditional glazing which helps towards reducing the amount of heat loss in the property.


Secondary Glazing - Stop Airplane Noise Secondary Glazing - Stop Railway Noise Secondary Glazing - Stop Traffic Noise



Product Specifications

General Information

Secondary Windows will be manufactured as a factory glazed product. The standard options will come complete with cover strips, catches and hinges where required.


All catches can be supplied non-locking or Allen Key Locking. Black Catches are available on RAL Colours.


Colour Options

  • White.
  • Silver Anodised.
  • Brown.
  • All standard RAL colours are available (subject to surcharge)



  • Black U-Channel Gasket


Glazing Thickness

  • 4mm Glazing
  • 6mm Glazing
  • 6.4mm Laminated


Glass Types

  • 6.4 Laminated glass for additional safety.
  • Pilkington K™ glass for increased thermal performance.
  • Stadip Silence Acoustic glass for enhanced noise reduction.
  • Obscure glass with 5 levels of privacy.


Toughened Safety Glass

  • Passes BS 12600-2002 Safety Glass for Use in Buildings

Technical Information

  • All sliding options will be supplied as standard configuration unless clearly stated on the order form.
  • All frames will be supplied glazed with 4mm single glass as standard.
  • Foam can be supplied in 5m rolls
  • All price list grids include 4mm annealed single glass as standard however we strongly recommend the use of toughened glass.
  • When panels exceed the recommended maximum sizes for 4mm glass it may be necessary to change the glass specification to achieve the panel size you require.
  • Glass panels should not exceed 1000mm x 1500mm when using 4mm float glass.
  • Lift out panels should not exceed 1.5m2 (at this size they weigh approx. 20kg). It is recommended that all panels that can be removed i.e. lift-outs and horizontal sliding panels are glazed with either 4mm Tuff or 6.4mm laminated safety glass.
  • Horizontal sliding panels should not exceed 2400mm high.
  • Maximum overall frame width available is 4700mm. (4 & 5 Pane Only).
  • All panel heights and widths are measured from the edge of frame to the centre of the mullion.
  • Vertical sliders should not exceed 1500mm wide x 2400mm high.
  • The horizontal and vertical slider outer frame is 50mm front to back and with a low 35mm sight line all round.
  • Vertical sliders up to 1000mm wide will be supplied with one Fitch catch. Wider vertical sliders will have two Fitch catches 250mm from each end.

General Information


Secondary windows will be manufactured as factory glazed product.


Standard features include Cover stripes and all catches or hinges where required.


All catches are white as standard (Black Catches are available on RAL Coloured frames) and can be supplied as non-locking or Allen key locking.


Size Restrictions


Glass Panels should not exceed 1000mm X 1500mm using 4mm Clear float glass.


If the panel exceeds the maximum size for 4mm float glass it will be necessary to change the glass specification to achieve the panel size you require.



It is usual after installing the Secondary window to fill gaps between the outer frame and the reveal.


Dependant on the size of the gaps and once the plastic screw cover trim has been fitted they can either be covered with D moulds (not supplied) or silicone/caulk sealed using the correct sealant. Acoustic mastic can be sourced from your sealant supplier.

Style Options