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Secondary Glazing

Aluminium Secondary Glazing

We supply and install a range of secondary glazing styles throughout Derry City, The North West and right across Northern Ireland. 

Secondary glazing is a fully independent internal window, fitted on the room side of the existing primary window. We fit a range of secondary glazing, designed to provide effective noise insulation, thermal and draught insulation and enhanced security. When glazed with low emissivity glass they can reduce heat loss by up to 65%. The comprehensive range of secondary glazing allows sympathetic treatment of almost any style of window.
All units are bespoke and designed with careful consideration to meet the needs of the project.

Secondary glazing has stood the test of time and still proves to be one of the best forms of protection for homes, public and private sector buildings and industrial units against heat loss, draught and noise intrusion. APG provide a comprehensive range of secondary glazing options to our customers.

Secondary glazing is a perfect solution for a conservation area, and listed properties where altering or replacing the prime window is not possible or cost-effective. It can even benefit those windows that are already double glazed particularly on noisy main road areas where noise is an issue.

Practical Benefits with Security in Mind

Feeling safe in your home is an essential factor when choosing to upgrade your windows. Secondary glazing, however, doesn’t involve replacing your existing frame but includes adding a second layer of protection. Using modern technologies, our glazing offers superior security for your home. 

Unlike singled glazing, our secondary windows are exceptionally difficult to break into from the outside. Provide your home with an additional protective barrier from unwanted intruders and guarantee your home an inherently strong and robust entry. Giving you the peace of mind that your home will remain secure.


Modern Properties

Secondary Glazing is not only for homes in listed and conservation areas; it also works well in more modern properties. Many customers opt for Secondary Glazing due to the level of road traffic noise, flight paths or a nearby railway.

With Acoustic Noise Reducing Glass you can leave the commotion outside where it belongs.


Modern Aluminum high performance

Key Features

  • Improves Thermal Insulation
  • Reduce noise pollution by up to 80%
  • Retain the character of your home
  • Fitted to any shape or size
  • Available in a range of colours and glass types
  • A secondary layer of security

Benefits of Secondary Glazing

Our systems have many benefits, should you be considering secondary glazing as an option to improve your windows then perhaps the key points below will help make your decision easier knowing you have made a great choice:

  • Save money on heating bills
  • Warmer rooms
  • Noise reduction
  • Improved security
  • Easy to open and access the primary window
  • Helps with condensation
  • Various glass options
  • Modern, slim and discreet
  • Customizable to fit any window type
  • Bay window compatible

Aluminium Profile options

Balanced Vertical Sliding - Sash Windows

Horizontal Sliding

Hinged- Casement Windows

Large Windows

Fixed and Slimline Options

Bespoke Made To Measure Secondary Glazing Options

Our Secondary glazing windows provides a comprehensive range of secondary style glazing to suit most applications, including horizontal sliders, hinged units, fixed and lift-out units, vertical sliders, balanced vertical sliders and tilt-in balanced vertical sliders.

Granada’s glazing has slim aluminium unobstructed frames. You can install the glazing by fixing it to your existing window, known as the face fix option. Or you can fix it into the window reveal, known as the reveal fix. The reveal fix is the most traditional way of installing secondary glazing due to its optimum performance.

Our slim-line aluminium secondary glazing is of the highest quality and can come in many styles and different options for any project.

Secondary Glazing Glass Options Available

Safety Glass

  • 4mm Toughened glass/ Low E optional extra
  • 6mm Float or Toughened glass / Low E optional extra
  • 6.4mm Laminated glass
  • 6.8mm Laminated acoustic glass

Sound Proofing Acoustic Glass

Secondary Double glazing Units

Secondary double glazing is specifically designed to provide you with sound reduction and heat loss. Many properties that are close by busy roads and other high noise areas can benefit enormously by installing our secondary glazing units.

Colour Choices

We can supply frames in white, silver or brown as standard but can also accommodate any RAL colour. We can also provide a wide range of glass types for your home in Bristol – such as clear, patterned, toughened, laminated and acoustic.

Thermal Performance

4mm Toughen with 

6mm Toughen

6mm Toughen Low E

Secondary Glazing- Supplied and installed in Derry City and across Northern ireland

Secondary glazing offers significantly improved thermal efficient and acoustic insulation and helps with condensation. This makes homes and buildings more secure, eco-efficient and cost efficient. Without the disruption of replacement windows.

Our Secondary glazing systems have been developed over 30 years to provide the insulation against external noise and improve the thermal performance in your windows. Secondary Glazing is suitable for properties of all sizes, ages and styles. Our high specification units offer a unique solution that is of particular interest to owners of listed properties, which are subject to tighter planning regulations.  

There are a number of window designs to choose from to help suit existing window and door setups. These tailor made units are made to exact specifications and combining the highly efficient sealing qualities makes our system the obvious choice, ensuring a perfect finish.

All windows in our range are aesthetically designed to be streamlined, seamless and contemporary, blending unobtrusively thus complimenting existing windows, doors and interiors. Each design shares distinct characteristics so when combining different windows i.e. a slide unit with a lift out unit, the two will blend to form a complete look. Arched and shaped units are also available for more challenging, architectural and creative window installations.

Our system is not the cheapest secondary glazing system you can find on the internet, but when you buy our system you are making an investment in a top of the range aluminium glazing solution custom made by experts. 

What Is Secondary Glazing?

Secondary glazing can be used with both single and double glazed windows to be installed discreetly inside the windows reveal an existing glazed window. Creating a version of double glazing 

Installing secondary glazing improves the thermal insulation, high levels of noise reduction and increased security of your window making it a cost effective way to reduce energy bills and improve the living environment for homes and work spaces.Secondary glazing is a fast and simple solution for homes, offices, schools, business premises, places of worship, and listed buildings.

Suitable for all types of construction including Grade I and Grade II listed buildings, hotels to commercial buildings, secondary glazing is suited for all types of premises.

From Horizontal Sliders, Hinged Units, Vertical Sliders, as well as Balanced Vertical Sliders and Tilt-In-Balanced Vertical Sliders, we supply a comprehensive range of of styles to suit every application. With a choice of frames in White, Silver or Brown and a wide range of glass types including clear, toughened, patterned, acoustic and laminated for any job.

We can cater for virtually every size and shape of window, our secondary glazing is unobtrusive, non-invasive and easily accessible for cleaning and ventilation, offering the benefits of replacement windows without the hassle and can be fitted all year round.

Advantages of secondary glazing:

  • Secondary glazing improves thermal insulation, dramatically reduce the level of heat that escapes from a property
  • Secondary windows help eliminate draught helping to create a more comfy enviroment.
  • Secondary glazing provides helps to reduce unwanted noise, aucsutic glass can sound proof your single glazed windows.
  • Secondary windows are cost effective and efficient way to improve existing windows rather than buying new windows. 
  • Secondary glazing is perfect when existing windows must be maintained in Listed buildings or conservation areas.
  • This secondary glazing is  slimline to discreetly compliment existing windows.
  • Reduce Condensation and protects traditional windows from wear and tear/ mold and wood rott improving their durabily. 
  • Available in a range of functional opening styles and designs choices of fixed, hinged, lift out, vertical & horizontal sliding units.
  • Secondary windows offer easy and clean installation.
  • Aluminium windows require very little  Maintenance.

Installing secondary glazing adds an extra barrier to prevent heat through your windows. The creation of an insulating layer of air is as important to the retention of energy as the fitment and seals. With the right secondary glazing and right specification of glass, heat loss can be reduced, energy bills to be cut and translating into an excellent investment as a result. With almost one-fifth of a home’s heat lost through single-glazed windows, secondary glazing helps reduce the cost of your household bills.

Secondary Glazing improves the energy efficiency of homes by providing insulation we can supply Low-emissivity K glass has a transparent coating which has been specifically designed to reflect heat back in to the room, reducing heat loss through the window and therefore energy consumption.

Draught Reduction

Traditional wooden sash windows can become susceptible to draughts, strong cold winds seeping in through gaps in windows can easily turn your rooms into a cold chamber no matter how much you spend on heating bills. Secondary glazing acts as an additional barrier between draughty windows and your home.

Older properties are notorious for being expensive to heat and keep comfy during the winter months

Lower fuel bills by reducing heat loss!
We are asked frequently if fitting secondary glazing will stop drafts and reduce heat loss — our answer is YES.

You will find that once we have fitted your new units you will see a marked reduction in both these areas. We have also find that this can help lower your fuel bills.

Secondary Glazing continues to grow in popularity, thanks to its unique sound proofing qualities, which is significantly better than double glazing. The key to minimising noise levels is to install an extra barrier that sound waves find it difficult to pass through. For many homeowners, traffic noise is their biggest concern. In these instances, correctly fitted secondary glazing and using thicker acustic laminated glass can make a world of difference. Secondary glazing has been specified by architects to reduce noise pollution. Alternatively those looking to keep noise in, such as the owners of pubs and music studios, secondary glazing is the perfect solution.

Older, traditional wooden windows rarely provide homes with sufficient security.  Our aluminium secondary glazing provides a supplementary protective barrier to your existing windows. Our system can in fitted with laminated glass which offers more resistance to physical attack than toughen glass.

Reduced Condensation

Clear – secondary glazing provides a complete internal seal, allowing balanced ventilation between your window and the secondary glazing. This stops the inner glass from becoming too cold and helps to tackle condensation. Build up of condensation on single window panes, due to difference in outside and inside temperature, will make a room damp. This can be accentuated during winter months so you must do all you can to keep your home warm and dry.

Secondary Glazing In Conservation Areas Of Northern ireland

If you are restricted by regulations on Listed Buildings or Conservation Areas, secondary glazing might be the right option for your home in northern ireland. It is suitable for all types of properties helping to bring all the benefits of double glazing.

Are you looking to improve your homes energy efficiency, noise pollution and condensation problems? Secondary glazing can provide you with a glazing solution without the need for double glazing. If you live in a listed property or conservation area then we have the perfect solution for you.

We carefully design each installation to use appropriate secondary glazing that will match the style & design of each primary window in your home in Bristol – making sure the Secondary Panel and Frame Sections line up with your primary window, mullions & transoms.

Once your secondary glazing is fitted, you can get on with your life as normal – enjoying the same uninterrupted views from your windows, while enjoying the benefits of a warmer, more comfortable, secure, quieter home – with reduced heating bills as a bonus!

Secondary Glazing For Derry City’s Conservation areas and listed buildings

Secondary glazing is particularly suitable for use in conservation areas and listed buildings were drafts and heat loss are often a particular problem  our system is the perfect solution for buildings where planning restrictions are enforced and original windows cannot easily be replaced, and it wont compromise the aesthetics of existing windows and frames.

 We are specialists in fitting secondary double glazing into properties where planning restrictions apply. For example, conservation areas where the removal of the original windows is prohibited. In this process, a completely separate aluminium frame and glass is installed on the interior portion of the existing frame or window reveal, thereby transforming your single-glaze window into one with a form of double-glazing and the associated benefits.


Retain the Character of your Home

Secondary glazing offers a solution to homeowners living in a listed building or conservation area that restricts them from upgrading their current windows. Typically windows in listed buildings or conservation areas will be single glazed and are unable to be replaced due to maintaining the character of the homes in the area.

Our secondary glazing offers a solution to your home improvement needs by adding a discreet internal window to the inside of your existing window. Providing a secondary layer of insulation without affecting the exterior of your property. Retain the character of your home in any style of property with our secondary glazing. 


Why choose secondary glazing?- Enjoy The Warmth And Comfort Of Modern Glazing

There are a variety of reasons why you may not want to replace existing windows. The windows may be in a listed building and protected by conservation laws, you may not want to remove beautiful traditional windows, or perhaps the single glazed units are still in good condition.

Protective Mechanism to Protect and Maintain Window Reliability

Secondary glazing greatly improves the longevity and reliability of your windows by providing a functional barrier from damage and daily wear and tear. As a result, secondary glazing is a superb choice for listed and aged buildings. Our team of glass and glazing experts will help you find the best possible glazing solution to fit your needs and budget.

Maintenance of Secondary Glazing is a Breeze

Secondary glazing  frames are made from tough aluminium and securely fixed requires only a small amount of maintenance, with little else being required other than occasional cleaning to keep them in the right condition. If installed with optional laminated glass  they will offer protection from UV sunlight from damaging the interior items such as photos and furnishings.

Improve Sash windows Transforming Single Glazed Windows

Simple – it can be retrofitted to virtually any building and building type, with little mess or intrusion. If you’re unsure on replacing your existing windows and would prefer to choose secondary glazing, get in touch today to see how we can improve your energy efficiency with secondary glazing.

Design and Functionality Of Custom Made Aluminium Frames Meeting your requirements

Designed by glaziers the strong aluminium frames can operate as vertically or horizontally opening windows we have designed a range of styles and designs. With a choice between sliding and fixed options, our secondary glazing service improves the functionality of your existing windows.

We have many styles of secondary glazing to suit your application and budget.  Each item is made to measure to ensure they fit perfectly and, with many years experience, we can offer excellent advice and knowledge. Our aluminium Secondary windows are white as standard, but are also available in standard RAL colour finishes to suit any decor or period home.

We will design and fit you the ideal solution. It could be vertical Sliders, Hinged Units and Horizontal Sliders, Balanced Vertical Sliders and Tilt-in Balanced Vertical Sliders. Whatever your individual requirements are we can provide a solution. It could be you require a face fix where the unit is screwed to the outside of the wall surrounding the window on the inside of the property. It could be reveal fix where it’s screwed to the inside of the window frame. What ever you need we have the solution.

Basic Insert
Lift Out
Horizontal Sliding
Heavy Duty

Installing Scondary glazing in Derry City – Clean and fast
All purpsoe glazing understand that disruption due to any building or repair work can be a problem. You will find that compared to fitting full double glazing to a property fitting secondary double glazing is a very clean alternative with far less disruption and will take a lot less time.

Supplying Bespoke Secondary Glazing Throughout  Derry City and right across Ireland

Our experience
We have extensive experience in fitting of secondary double glazing into many different properties which include:

  • Listed buildings: grade one and two,
  • Domestic properties:
  • Educational buildings: Schools, Colleges and Universities.Traditional Sash windows Secondary glazing Derry City Northern ireland home improvments
  • Commercial properties: Hotels, Offices, Public buildings, Shops.

Visit us


The Glass Works, Skeoge Industrial Estate Beraghmore Road Derry City BT48 8SE

Call us


+44 (0) 2871 357 555

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