Secondary glazing noise and sound insulation properties





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Mobile : 07875 369 855



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North London Secondary Glazing
Unit 4
Noke Lane Business Centre
Noke Lane
St. Albans, Herts



Secondary glazing noise and sound insulation properties



Secondary Glazing Products


Find out more information about the different types of secondary glazing we can provide



Vertical Sliding Secondary Glazing



Our Vertical Sliding Secondary Glazing is ideal for providing thermal insulation and sound proofing for traditional wooden box sash windows, or any other windows that have horizontal bars. Panels slide up and down in the same way as vertical sliding sash windows and provide easy access to the existing window. When open they provide ventilation without interfering with curtains or blinds.


Vertical sliding secondary glazing has been designed especially for secondary glazing sash windows. Secondary glazing for sash windows mirrors the primary sash window - consisting of two secondary sashes, one above the other, securely retained in their own outer frame.


Sight lines of the secondary double glazing for sash windows match a traditional sash window and each secondary sash is easily released for opening by way of the factory fitted side shoot bolts which then re-engage in pre-positioned keeps for variable ventilation. Inner panels are easily removable to allow access for cleaning and maintenance. Suitable for Listed Building sash windows, Conservation Areas & all other properties with sash windows.



vertical slider unit glazing  high quality vertical slider secondary glazing vertical  silders vertical slider glazing panels

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Vertical sliding secondary glazing units can be used for a number of different applications.



  • Over traditional sash windows of all types, sizes and ages
  • For arched sash windows
  • Over stained glass for insulation and protection



  • In combination with other secondary windows in sash bay windows
  • For shaped sash windows
  • In combination with other secondary window units where sash windows are next to doors


Sizes, Guidance & Restrictions


4mm clear float glass
6mm clear float glass

1200mm width x 1800mm height
1200mm width x 1500mm height


You can contact NLSG any time to find out more about our up-rated specifications to accommodate larger size secondary glazed windows subject to safety considerations such as the weight of the secondary sash panels for safe handling, the specific application and any potential detrimental effect on the units' performance.


To enable cleaning the secondary sash window should be fitted at least 75mm in front of the primary sash window. The width to height ratio ideally secondary sash windows should not be greater than 3 widths to 1 height ratio in order to prevent the sashes "crabbing" when being opened & closed.



Vertical Sliding Secondary Glazing Windows - Standard Product Range


  • black gaskets
  • 4mm clear float glass
  • panels removable for cleaning
  • direct fixing subframe - 21mm x 45mm
  • white frames & sections
  • white interlock fitch catch
  • integral timber subframe
  • reveal fixing subframe - 21mm x 62mm



Manufacturing Options


  • Van Dyke Brown powder coated finish
  • silver anodised finish
  • woodgrain effect powder coated finish
  • standard fitch catch on central interlock sections (silver or gold)
  • locking fitch catch on central interlock sections (white, silver or gold)
  • Chubb Locks
  • restricted opening locks
  • standard vent - for adjustable trickle ventilation 4000mm² requires additional 21mm sub frame at the head (total 42mm)
  • acoustic vent with integral fly-screen - for adjustable trickle ventilation 1600mm² requires additional 21mm sub frame at the head (total 42mm) - reveal fix only, requires internal clearance for the baffle - supplied complete with 60mm pre-routed cover architrave
  • integral timber subframe for a bay window - angled one or both sides
  • chamfered timber subframe for square bay windows for optimum sight lines
  • without subframe
  • white gaskets
  • 6 standard RAL colours - pure white, ivory, cream, magnolia, grey, jet black
  • any non-standard RAL colour finish
  • glazing - from 4mm up to 7.5mm - for thermal insulation or sound insulation
  • shaped units - curved, semi-circular, arched or Gothic heads



Contact the NLSG team to find out how we can help you.