How to Install Secondary Glazing

Secondary glazing is a great way to improve the energy efficiency of your home. It's a relatively affordable and easy way to add an extra layer of insulation to your windows, which can help to keep your home warmer in the winter and cooler in the summer.

In this blog post, we'll show you how to install secondary glazing yourself. We'll cover the basics of what you need to do, as well as some tips and tricks to make the job go smoothly.

Sekosnap secondary glazing is easy to install secondary glazing that can be installed by any DIYer or Tradesman with just basic DIY Skills! Unlike other options available, Sekosnap Secondary glazing is fully aluminium so has an estimated lifespan of 20 years.

What is DIY Secondary Glazing?

Sekosnap DIY secondary glazing is a system that adds a layer of glass to your existing windows. This creates an insulating barrier that helps to keep your home more comfortable and energy efficient. There are a variety of different DIY secondary glazing systems available, so you can choose the one that best suits your needs and budget.

Why Choose DIY Secondary Glazing?

There are many reasons why you might choose to install secondary glazing on your home. Here are just a few:

It's affordable. DIY secondary glazing is a much more affordable option than replacing your windows altogether. Secondary glazing costs can be as little as one-third of the cost of new windows.

It's easy to install. DIY secondary glazing is relatively easy to install, even for people with limited DIY experience. With the below and all the necessary hardware, you can have your new secondary glazing installed in no time.

It's effective. DIY secondary glazing can be very effective at improving the energy efficiency of your home. Studies have shown that installing a secondary gazing kit can even reduce your energy bills.

It's versatile. DIY secondary glazing can be used on a variety of different window types, including single-glazed windows, double-glazed windows, and even patio doors.

How do I install Secondary Glazing? Good question! Below you will find the installation guide for your Secondary Glazing DIY project:

What You'll Need to Install Secondary Glazing:

- Drill with HSS Drill bit
- Hacksaw (Fine toothed blade for the smoothest cut)
- Marker Pen
- Tape Measure
- Rubber Mallet (optional)
- Jigsaw (optional – for trimming sheets to size)

Secondary Glazing Installation steps

  1. Always wear the correct safety equipment before you start; particularly when cutting parts to size.
  2. Start by measuring the internal size of your window or frame. If you are creating a mitre joint at the corners, the internal frame size will equal the inside mitre size. Alternatively, if you are implementing the butt joint method, add 27mm on either side to this inside measurement.
  3. Accurately mark your Secondary Glazing lengths to match. Remember that if you want to have the Secondary glazing set back on your you frame then simply add to these dimensions.
  4. Clamp the Secondary Glazing lengths down on a workbench (or similar)
  5. Select a metal blade for your hacksaw and separate the base and top bars to cut individually. Begin with a few push strokes to create a groove in the bar to follow when cutting.
  6. As you continue across the secondary glazing bar you can speed up your cutting to suit.
  7. Sekosnap® Secondary Glazing comes pre-drilled at approximately 250mm centres so depending on where you cut it is best to add extra holes at the end of the cut lengths for strength. Use a drill with an HSS bit to drill any additional holes required in the base bars.
  8. Starting from the bottom, screen in each base bar. Take care to ensure the screw heads are below the clips on the profile and avoid screwing too fast to preserve your window frame. (Top Tip: If you want to have scope to align the corners it is wise to screw in partway to then align and fully secure)
  9. Match your glazing sheets to the frame and trim to size if required. Remember to add 10-12mm to your sheet measurement for each side. To view our cutting construction video please refer to a solid glazing sheet cutting guide.
  10. Peel back to Protective Sheet Film on the front face by approximately 50mm
  11. Remove the protective film from the back of the polycarbonate sheet entirely
  12. Line up the Secondary Glazing top clips on the sheet one by one and slot the, over the edge. Ensure the corners align and are square as possible.
  13. Offer the sheet, now with Secondary Glazing Top clips slotted on, up to the bottom of the frame and position the bottom top bar over the first base bar
  14. Align the top and sides and check the corners are square and neat. Then slowly snap the Secondary Glazing® together, starting at the bottom and working upwards. (Top Tip: Gently use a soft rubber mallet to help snap in larger glazing panels)
  15. Finally, remove the front protective film completely!

What Glazing Sheet to Use for Secondary Glazing?

There are many different types of glazing sheets available on the market, but Axgard polycarbonate sheets are the best option for four main reasons:

Virtually unbreakable. This makes them a safe and secure choice for secondary glazing, especially if you have young children or pets.

Lightweight and easy to install. This means that you can do the job yourself, without the need for professional help.

UV-protected. This means that they will not fade or discolour over time, even when exposed to direct sunlight.

Available in a variety of thicknesses and colours. This gives you the flexibility to choose the right sheet for your specific needs.

If you are looking for a safe, secure, and easy-to-install glazing sheet for secondary glazing, then Axgard polycarbonate sheets are the route for you.

What thickness of Glazing Sheet to use for Secondary Glazing?

Secondary glazing is generally compatible with 2mm and 3mm thick glazing sheets, like Axgard. While both are great options, the 3mm Polycarbonate sheet is best as it provides extra rigidity, especially for larger window areas.

If, however, you are installing secondary glazing over a small window frame you may consider 2mm as the more budget-friendly option. Always take into consideration the overall size of your window to ensure the thickness is suitable for the span.

Should secondary glazing corners be mitre or butt joined?

Mitre joints are created by cutting the edges of the glazing at a 45-degree angle and then fitting them together. This creates a strong and aesthetically pleasing joint. However, mitre joints can be more difficult to install than butt joints but will give the best overall finish.

Butt joints are created by simply joining the edges of the glazing together. This is a simpler and quicker method of installation, but it is not as strong as a mitre joint. Butt joints are also more likely to show gaps, which can let in air and noise.

Secondary Glazing Corner Options

The best way to join the corners of your secondary glazing will depend on your individual needs and preferences. If you are looking for a strong and aesthetically pleasing joint, then mitre joints are the best option. However, if you are looking for a simpler and quicker installation, then butt joints may be a better choice.

Can you remove the Secondary once installed, if required?

One of the great features is the ability rapidly remove if required by simply hooking the removal flange and pulling the top cap at an angle to release. This ensures you can easily remove your Secondary Glazing system for window maintenance or to replace any panels if damaged.

How to Cut Glazing Sheets to Size for Secondary Glazing?

Selecting the correct glazing sheet for your secondary glazing is very important to make cutting the sheets easy and their lifespan long. Choose a fully UV Protected sheet, like Axgard Clear Sheeting, which is easy to cut without splintering or cracking.

Acrylic sheets are best avoided for secondary glazing as they are hard to cut to size and go brittle. Never use styrene sheets for secondary glazing as they have no UV protection and are very brittle.


Would you like further help with a Secondary Glazing Project?

Simply jump on our Live Chat or via email where our Teams will provide you with all the advice and support you require for your project.

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