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insulation sound proofing draught proofing stop condensation
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Extraglaze Explained
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  • 1 week ago
    ratings 5
    Canal boat condensation
    Service rating : I live on a canal boat and condensation is a problem. I have 13 windows now fitted and absolutely delighted.

    No condensation and warmer air. The sealing tape is excellent.

    Can't wait for winter.

    I wholeheartedly recommend Extraglaze.
    Product : I live on a...
    Steve Brown, Hemel Hempstead
  • 1 week ago
    ratings 5
    Extraglaze is a superior first class product.
    Service rating : I ordered Extraglaze for one large bay window which has four stained glass panels at the top. Nic from Extraglaze came to measure up and gave advice and detailed information on the whole process. He returned to fit the eight panels in all on two more occasions and throughout the...
    Angela Jones, Coventry
  • 1 month ago
    ratings 5
    Excellent product and service.
    Service rating : The service was excellent. Very helpful staff who gave you useful advice. Panels fitted perfectly and matched surrounding woodwork in honey oak. The magnetic strips and panels are hardly noticeable. I'm very pleased with the secondary glazing eliminating draught and condensation and have...
    Beryl Watkins
  • 2 months ago
    ratings 4
    Service rating : Good web site, the product was well explained. They recommended an expensive but very good fitter and the panels were delivered on time.
    Product : So far, it was only fitted yesterday, the product is exactly as explained. It has cut noise from the road, it is relatively subtle - much...
  • 3 months ago
    ratings 5
    Care taken.
    Service rating : Prompt service, no quibble and product shipped in well constructed packaging. Obvious that care had been taken
    Product : Just what I wanted. I am converting a summer house into an art room. Thinking about the cold in winter I was pleased to find easily fitted secondary glazing at a...
    Judith F Hubbard

Extreme Adhesive Test



We wanted to prove our adhesive is the best!

Proven to improve


coventry university logo bre logo


The Building Research Establishment and Coventry University complete tests of the Extraglaze system
Soundproofing and thermal test results...


Recommended for Listed Buildings


Telford and Wrekin Conservation Department encourage the use of secondary glazing, where possible, to increase thermal efficiency.




Does Extraglaze stop condensation?

Extraglaze can be an excellent long term solution, reducing and more often than not eliminating condensation. For a day or so after fitting it is common to still experience a little condensation on the original window, because the fitter breathes all over the window while working, and his/her breath is caught in the gap as soon as the panel is applied. However on a dry day the panel can be removed, for dry fresh air to replace the damp air. Condensation does not usually return (unless there is a fresh source of dampness within the window itself e.g. leaks or damp wood or bricks). Instances of mould are reduced dramatically, usually eliminated, as the cavity stays dry. Consequently the life of the paintwork on an intricate window frame is greatly extended, and stays looking fresh.

You may read that secondary glazing does not solve condensation. This is commonly known for secondary glazing made of glass. Extraglaze however is superior to other types of secondary glazing because the acrylic can maintain a comparatively warm surface. A chill does not pass through the acrylic nearly as well as it can through glass (glass will transmit heat about 5 times faster. Please note there are some incorrect statements on the internet that suggest it is the other way around!). So the inner pane of your window, i.e. the Extraglaze, is not prone to collect condensation.


IMPORTANT NOTE: Condensation is a symptom of insufficient ventilation i.e. a humid indoor atmosphere. Extraglaze does not cure this. Humidity is commonly a result of steam from showers & baths, kettles, poorly vented tumble dryers, cooking pots and a busy house full of people. Condensation may settle elsewhere i.e. humidity may condense on another cold spot in your building. Condensation is most common upstairs, because humidity rises up with hot air. If you still experience condensation after Extraglaze has been fitted then do check it for gaps i.e. where the magnets may not be mating correctly. This suggests incorrect fitting. If there are no obvious gaps then this is a warning sign that you have an abnormally humid room (therefore poorly ventilated or entirely unventilated) and action is required to reduce this. Such poor ventilation is very likely harmful to your health and the fabric of your building.


What depth of air gap is best on my windows?

For thermal efficiency a 75mm air gap (or cavity) is ideal, but on many windows this is not practical (and unheard of on domestic double glazed windows). In practice any gap over 25mm is still a good one. Less than 25mm and more than 100mm is not nearly so effective. Deep air gaps can still be very satisfying (far better than no gap at all), but the large cavity allows air to circulate and so heat is transferred from outside to inside. For sound insulation a gap of 30mm is moderately effective, increasing in effectiveness as the gap gets larger. In our tests at the Building Research Establishment we found an optimum at 125mm, after which the rate of benefit slopes off. However please do note that larger gaps compromise thermal effeciency.




How do I keep Extraglaze clean?

Extraglaze must only be cleaned with an new/uncontaminated microfibre cloth. Please never use any other type of cloth, and never use a paper tissue (tissues usually contain tiny amounts of a mineral powder which will scratch just about anything!). Microfibre cloths are very cheap and very easy to find in any supermarket or hardware store. A very clean soft cotton cloth might sometimes be acceptable, but is nowhere near as effective as a microfibre cloth. Whereas a microfibre cloth will literally grasp dust particles as soon as it comes in contact, a cotton cloth will just sweep some of the dust around.


What cleaning agents shall I use on Extraglaze?

Extraglaze panels are best cleaned with Vu-plex anti static cleaning fluid (this was specially developed for the aviation industry, for cleaning cockpit windows). A tiny amount will clean and polish an Extraglaze panel in a few seconds with minimal effort (always using only a microfibre cloth). You can buy Vu-plex in our online shop. If you employ our "Fitted by Us" service then we will supply you a can of this at the end of the project. You can also use very dilute solution of soapy warm water, though without both the anti-static and the polishing effects.




Is acrylic better than glass?

Acrylic is better than glass in many ways. It is safer, as it can take a hit unlike glass (acrylic will certainly never be as dangerous as broken glass). It is also much lighter, at least half the weight of glass (plus Extraglaze has only magnets rather than a frame). For these two reasons Extraglaze is safe and easy to lift away to open or to clean your windows. For secondary glazing purposes acrylic is also flexible enough to take on the shapes of old timber window frames, and numerous layers of paint, which are often far from perfectly flat. Trying to attach a glass panel using magnets in the same way will almost certainly fail, and indeed be very dangerous!


Why do you use acrylic for Extraglaze panels?

Acrylic is an excellent choice for Extraglaze panels. Acrylic has been used in lots of glazing applications for many years, including safety guards, motor cycle helmet visors, police vehicle protection, greenhouses and even aircraft cockpit hoods. It is tough, does not warm up and expand like other plastics in the sunshine, is unaffected by UV rays, does not discolour and is optically very clear indeed.


Are the acrylic Extraglaze panels brittle?

No. Acrylic is known as an "engineering polymer" which means it is a premium material of choice for important components in all kinds of tough environments. We have first hand experience of dropping quite large panels (by accident of course!) - we worry more about the damage the panel might do than the damage to the panel itself!




What colour are the magnets?

The magnets supplied by Extraglaze have a white top surface i.e. all the major surfaces you see when the panels are in place, and when they are removed. Other colours are available when you place your order, or why not request a free sample? The edges however (about 1.5mm) are dark brown, which is rarely of consequence. The selected colour will be applied at the factory. Alternatively if you know the paint colour on your frames then the perimeters where the magnets are can be painted* the same colour as your window frames (extra charges apply.)

*PLEASE NOTE: at the factory we can only paint the panels i.e. around the perimeter. If the foundation magnets are to be painted then this has to be done after they are fitted to your window. For this reason we prefer not to paint the magnets – instead we would usually apply a special coating of a similar colour from our colour chart at the factory. If, however, painting the foundation magnets is critical, i.e. after installation, then this is an extra chargeable service (unless you wish to do this yourself).

What are “foundation magnets” ?

The “foundation magnets” are those that remain on the frame even after the panels are taken away. Please note that the panels also have magnets, permanently on the panel around the perimeter.


Can I paint the “foundation magnets” ?

Yes. These should be rubbed clean with a fresh cotton cloth, then painted with a primer, undercoat and top coat just like you paint the window frames themselves. If this is your plan then it is best to ask for natural colour foundation magnets, which have not already been coloured (the natural colour is a very dark brown, otherwise we supply the foundation magnets with a white surface as standard, which should not be painted.)



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Help & Guides

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How to stop condensation


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