Secondary Glazing

Secondary glazing is an effective way to improve the temperature of your home, as well as reducing sound pollution and enhancing the security of your property. It’s an affordable alternative to traditional double glazing that provides just as many great benefits, and with styles of installation that are sympathetic to period properties and historic homes. At Cut My Plastic, we can cut acrylic sheeting to any size or shape for your secondary glazing needs, to ensure that the fit is accurate.

What is secondary glazing?


Secondary glazing works by fitting a discreet internal window into an existing single or double-glazed window to make it more insulating and efficient. Because of the optical clarity that acrylic provides, there’s no discernible difference between the visibility or light transmission of your single glazed windows and the results of secondary glazing. It’s often a preferable alternative to double glazing, particularly for heritage properties, as it doesn’t detract from the external character and look of the windows but gives all of the benefits. Acrylic is easy to fit, due to its lightweight qualities, and can be removed easily too – so in the summer, you can take your secondary glazing panes out if you wish to and fit them again in the winter.

What are the benefits of secondary glazing?


When you install secondary glazing into your property, you achieve the same insulating benefits of double glazing, such as lower energy bills and improved heat transfer. Secondary glazing can reduce heat loss via windows by around 65% which is 10% more than double glazing provides. This means your home will stay warm in the winter and cool in the summer. Another benefit is that it also insulates against sound and enhances the security of the property. Secondary glazing also provides better value than double glazing, as it’s more cost effective, can be removed easily if need be with certain styles and it’s subtle, so historic homes can retain their character while still reaping the rewards of a warmer and more soundproof home.

Secondary glazing offers incredibly effective sound insulation, more so than traditional double glazing, and can help to reduce noise levels by as much as 80%. When using secondary glazing for this purpose, we suggest choosing a different glass thickness to what is in place already, as this will decrease sound reverberation. It’s an affordable and highly effective method for enhancing the security of the building as well. It can even be fitted easily to wooden window frames. If you live on a busy road with lots of traffic noise, installing acrylic secondary glazing panels to your windows can help reduce these noises significantly and will act as an effective sound barrier. Acrylic is far more secure and impact resistant than glass, offering a second barrier of protection from the inside that will deter thieves and protect those inside from outside hazards. And because no external access is required, it’s ideal for multi-storey buildings.


If you need any advice or have a question regarding secondary glazing for your home, give our friendly team a call and we’ll be happy to talk you through the best options for your home.


Magnetic Secondary Glazing

Magnetic secondary glazing is a removable secondary glazing panel which is held in place using magnetic tape which can be purchased in our accessories section. This type of secondary glazing is great as it’s easy to install without the need to hire contractors to do the work for you, it’s cost-effective compared to traditional, permanent double glazing, plus it provides a reduction on your energy bills. Should you want to remove it at a later date, it can also be uninstalled with ease.

Magnetic secondary glazing works by using magnets to hold the panels in place, so it’s secure but can also be removed easily if need be, such as during the summer if you need to access the window beneath it or for emergencies. The self-adhesive magnetic tape is matched to the colour of the window frame, making the strip virtually unnoticeable when the panel isn’t installed. All that’s required is to align the magnets with the strips on the perimeter of the window and press into place. It’s an easy way of keeping the heat in your home, lowering your energy costs and reducing the risk of condensation from building up.


Secondary Glazing for Sash Windows

Traditional sash windows are typically found in Victorian properties, country cottages or heritage and listed buildings. These types of structures are notoriously poorly insulated because of the age of the buildings, and sash windows can be a large source of this heat loss. In addition to losing heat, they can also be draughty and noisy during windy weather, as well as being prone to condensation build-up. Because of the age of many sash windows, they can also be less secure and pose security risks, as they’re easy to break into, often without even breaking the glass itself.

One way to avoid the problems associated with sash windows, without having to remove them and still maintaining the original look of the property, is through secondary glazing. The benefits of secondary glazing, such as reducing heat loss, minimising condensation and keeping outside noise at bay, helps to eliminate the issues that sash windows can bring up and still ensures that the overall look of the building is preserved.

In addition to all of this, secondary glazing also helps to improve the security of the property and can be removed at a moment’s notice if necessary. This cost-effective solution is great for adhering to the regulations that listed or heritage buildings have while still benefitting from the properties of additional glazing.

DIY Secondary Glazing

Our secondary glazing options are easy to fit yourself using magnetic tape, so all that’s required is for you to measure the window for the exact size of acrylic panel you need and order the tape. Once you have your items, it’s simply a case of putting them in place. We’ve provided a guide below for installing your secondary glazing to ensure the perfect fit and professional results.


Measuring for Secondary Glazing

We suggest ordering 2mm acrylic for your glazing, although if you have larger windows then 3mm or 4mm will provide you with more rigidity and stability. To measure for your glazing panes:

·       First measure the length and width of the glass window pane that you’re looking to secondary glaze.

·       Next, measure the visible glass and add a minimum of 30mm to the length and width measurements you have, so you have plenty of space to attach the magnetic tape and fix it into place on your window frame.

·       Send these to the team at Cut My Plastic and we’ll do the rest.

·       Once you’ve ordered your panels, select the number of rolls of magnetic tape you also require. The tape comes with steel tape to attach to the window frame and magnetic tape to attach to the acrylic panel, ensuring a quick and easy solution to heat loss and noise reduction, as well as instant access to your windows for easy ventilation and cleaning.

We recommend ordering the panels to cover the whole of the window frame as this makes for a more aesthetically-pleasing installation and will help the secondary glazing blend in to your current windows.


Installing Secondary Glazing

To install your glazing panes:

·      Cut and stick the magnetic strip to the acrylic window pane.

·      Hold the acrylic window pane up to your current window so that it overlaps the frame equally on each edge.

·      Use a pencil to draw around the acrylic pane onto the window frame and then stick the steel strip to the frame itself, just inside of the pencil markings.

·      Lift the pane up to the window and firmly click it into place. Ensure you fit the secondary glazing to the frame and not to the opening part of the window.

Please Note:

·      Check that the existing window frame has at least 15mm of mounting surface available all the way around for secure installation.

·      Magnetic secondary glazing isn’t recommended for sloping windows or ceiling and roof windows.

·      If you’re installing secondary glazing for larger windows of 1200mm x 1200mm or bigger, opt for 3mm acrylic instead as this will provide more rigidity. We also suggest placing a few screws immediately below the panel to provide additional support and prevent the panel from slipping down.