Secondary Glazing

Secondary glazing involves adding an extra slim-line window in addition to your existing windows. It is very useful for listed buildings and conservation areas.

What Is Secondary Glazing & Where Is used?

Secondary Glazing is an internal window fitted to the inside frame or reveal of the main window. Ideal for listed buildings where replacement is not allowed or for addtional soundproofing the secondary window can either slide or hinge.


  • Leave the prime window unchanged – If you can't replace your windows or feel that you would prefer to leave them unchanged then secondary can provide you with extra thermal and draught insulation.
  • Cost-effective Insulation Solution – Secondary double glazing is cheaper than replacing the window. However you will only get about 50% of the heat saving provided by sealed unit double glazing in a replacement window.
  • Effective soundproofing – When you install secondary glazing, the first thing you will notice is that it is quieter. In fact secondary glazing is better at reducing sound than traditional sealed unit double glazing. This is because the two panes of glass are further apart from each other. 
  • Easy to Clean - All horizontal sliding secondary panes lift out for cleaning and all vertical sliding panes tilt into the room for cleaning. 




  • Chartered Trading Standards Institute
  • Glass and Glazing Federation
  • Fensa
  • Conservatories Association
  • Trust Mark
  • GGFI

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