How to fit secondary glazing to an aluminium sliding window
Quick answer: On a typical Australian aluminium sliding window you have two choices: one panel over the whole frame, which seals best and lifts off when you want to open the window, or a panel over the fixed pane only, which leaves the sliding half working as normal. You need a flat face of frame at least 25mm wide on every side for the steel strip.
Option 1: one panel over the whole window
Stick the steel strip around the inside face of the outer frame and fit one panel that covers both panes. It traps the most air and also covers the gaps around the sliding sash, which is where sliders leak draughts. In winter you leave it on; when you want fresh air you lift it off and lean it somewhere safe.
Wide sliders often need two panels that meet on a steel strip down the middle, because a single panel has to stay under 2000mm on its longest side and 2 m² in area.
Option 2: fixed pane only
Fit a panel to the frame around the fixed pane only. The sliding sash keeps working, but that half stays single glazed and the sash gaps still leak. It's a fair compromise for a window you open every day.
Measuring a slider
- Check the inside of the frame is flat and at least 25mm wide on all sides. Window locks, winders and the sash handle can get in the way, so note where they are.
- For option 1, measure the glass-and-sash opening inside the frame and add 40mm to each size.
- For option 2, measure the fixed pane's opening and add 40mm, then check the panel won't hit the sash when it slides.
- Send us a photo with a tape measure across the window if you're not sure. We check sizes before cutting.
Questions
Can you put secondary glazing on sliding windows?
Yes. Either fit one panel over the whole frame and lift it off to open the window, or fit a panel to the fixed pane only so the sliding side still works.
Will a magnetic panel stop draughts from a sliding window?
A panel over the whole frame covers the gaps around the sliding sash, which is where most slider draughts come from. A fixed-pane-only panel won't.
How wide does the frame need to be?
At least 25mm of flat frame on every side, so the 25mm steel strip and the panel's magnetic tape can meet.
What about the flyscreen?
On most Australian sliders the flyscreen is outside the glass, so an inside panel doesn't touch it.
How big can one panel be?
Up to 2000mm on the longest side and 2 m² in area. Wider sliders use two panels that meet on a steel strip.