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Secondary Glazing

Frequently Asked Questions
  • What is Secondary Glazing?
    Secondary glazing involves adding an extra slim-line window in addition to your existing windows. It is an effective and cost efficient method of insulating and sound proofing your windows and will save you money on heating bills.
  • What is your Secondary Glazing made of?
    Our secondary glazing systems are made from aluminium, they use high quality hard wearing rubber gaskets and not polypropylene to hold the glass in place. Our Luxury Subframe system has an optional wooden frame that wraps around the aluminium frame.
  • What is the difference between your Economy Odd Leg and Luxury Subframe systems?
    The main difference is that the Luxury Subframe system has a wrap around wooden frame that enables you to be able to reveal fix or face fix your secondary glazing. The Luxury Subframe system has a nicer, cleaner finish than the aluminium flange of the Economy Odd Leg system, which makes it more suitable for use in domestic applications. Find out more »

    The Economy Odd Leg system is a face fix only system, the advantage of this system is that it is slightly quicker to fit and comes at a slightly reduced cost when compared to the Luxury Subframe system - you have around the same amount of aluminium but save on the wooden subframe and trims. This could save you a substantial amount of time and money on a commercial job of 200+ windows. Find out more »
  • What does ‘face fixing’ mean?
    This phrase refers to the way in which the secondary glazing is fitted. To face fix secondary glazing means to simply mount it directly onto the inside face of the existing windows.
  • What does ‘reveal fixing’ mean?
    To reveal fix secondary glazing is to fix it through the sides of the frame into the interior wall on either side of the existing window, or window reveal. By fixing it to the side face of the wall that lies between the existing window frame and the inner wall, you can maximise the air gap between your windows and the secondary glazing.
  • I don’t think single glazing is going to be enough. Do you supply double glazed secondary glazing?
    Yes. Our Heavy Duty system can take 20mm hermetically sealed units. It is a direct fix system that is fitted into the window reveal. It can also achieve larger maximum sizes than our other secondary glazing systems.
  • What glass should I specify for the best sound insulation?
    The best glass for sound reduction is ‘Acoustic Stadip’, but it is quite pricey. You can greatly improve sound insulation and reduce external noise, by specifying thicker glass or simply glass that is a different thickness (and therefore a different resonation factor) to the glass in the existing window. Inserting acoustic tiles (not supplied) can help dissipate noise within the air gap. Specifying a wooden subframe actually helps to improve sound insulation. For more on the benefits of secondary click here »
  • What is safety glass and when should I specify it?
    When choosing your glass you need to take into consideration the glass safety regulations. Generally; glass up to a height of 800mm up from finished floor height, plus glass in doors and adjacent to doors should be safety glass. Conventional float glass is not considered to be safety glass, in these critical locations you must specify toughened or better glass. For more info please download our Glass Safety Regulations PDF »
  • I want to decrease my heating bills. What glass should I specify for the best thermal insulation?
    The glass with the best thermal properties is our Pilkingtons ‘K’ glass. You can also take advantage of your window reveal, as the air gap / cavity formed between the prime and secondary windows is an effective thermal insulator. Specifying a wooden subframe will also help to provide improved thermal insulation. Find out more about the optimum air gap.. »
  • Will adding secondary glazing eliminate draughts?
    Yes, it certainly can do, however we recommend that you draught proof the existing window as well.
  • Does specifying toughened glass improve thermal or sound insulation?
    No not really. Toughened glass does not have any additional insulating properties when compared to float glass. Toughened glass is simply safety glass that can be specified for added security or in circumstances where it is necessary to meet the glass safety regulations. Our 6.4mm Laminated glass can provided added security, additional sound and thermal insulation (when compared to 4mm float) and is also a safety glass. Find out more glass safety regulations. »
  • What colours can I have?
    White, brown and silver are all stock colours. We can also colour your frames in any of over 200 RAL colours. When specifying a RAL colour you may choose a matt, semi-gloss or gloss finish. As RAL colours are completely custom painted for your order they will cost a little more and lead times will increase.
  • Do all panels slide with your Horizontal Sliders?
    With most styles of Horizontal Slider all the panels slide as standard. However you can choose to have the centre panel fixed on a three panel, two track, horizontal slider. This fixed panel can still be extracted for cleaning after the two sliding panels are removed.
  • What's the difference between 2 track and 3 track Horizontal Sliders?
    A two track horizontal slider is very much the industry standard. A three track horizontal slider is a deeper frame that is only available for a three panel horizontal slider. It enables each panel to slide in its own track, so that when all the panels are slid open they can stack behind one another. This provides over a two thirds opening and increased ventilation.
  • Can you provide me with a sample?
    Yes. We can also provide survey kits, which contain off cuts of each of our secondary systems. Please contact Sales for more information.
  • Is your secondary glazing easy to assemble and install?
    Due to the uncomplicated nature of our Secondary Glazing it is pretty straightforward to assemble and install. The sliding panels come made up and fully glazed and the majority of the time they can be delivered fully assembled within the frame ready to be installed. The only reason your outerframe may be supplied in knock down kit form is if access is a problem or the units are particularly large. Secondary glazing is quick and simple to install, mess free and you won‘t even have to re-decorate. Considered to be a reversible change, secondary glazing is recommended by English Heritage and the Listed Property Owners Club. Good-quality secondary glazing is also recommended by the Energy Saving Trust and they also say that low emissivity glass will improve the performance of secondary glazing.
  • How can I get a price?
    We do not give out prices over the phone, in order to protect our trade customers. The fastest way to get a price is by using our online estimator. You can however send us details of what you want us to quote by email or fax and we will try to return your quote within 24hrs. Try out our online estimator.
  • The sliding panels on my horizontal slider do not interlock correctly. What have I done wrong?
    This is due to the fact that the panels have been inserted into the frame incorrectly, they need to be inserted into the frame in a certain way (the same way they came out). They will only interlock correctly when the panels in the second track are inserted last and from the correct side. Please see our instructions in the PDF link below. Secondary Glazing Panel Insertion Guide (PDF)

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