Maintenance and Cleaning Your Secondary Glazing
Four glass faces instead of two is the objection we hear most often, and it is a fair one. Every unit we fit is designed so both cavity faces can be reached without tools or with a single thumbscrew.
Cleaning by format
Sliding units: slide one panel fully clear and clean the exposed faces, then reverse. Hinged units: open the casement and clean both faces as one. Lift-out panels: lift the panel out of its rebate, rest it on a soft surface and clean it flat, which is the easiest of the three. Fixed panels are unscrewed from the frame — a few minutes, once or twice a year.
- Sliding: slide clear, clean, reverse
- Hinged: open and clean both faces
- Lift-out: remove and clean flat
- Fixed: unscrew, typically annually
What to use and what to avoid
Warm water with a little washing-up liquid and a microfibre cloth on both glass and frames. Avoid solvent cleaners, abrasive creams and anything with ammonia near the gasket line — ammonia hardens EPDM over time and a hardened gasket stops sealing. Never use a blade on coated glass.
The annual three-minute check
Once a year, run a finger along the gasket for hardening or shrinkage at the corners, wipe the bottom track clear of grit, put a drop of dry PTFE lubricant on the running gear, and check the locks turn cleanly. That is the whole maintenance schedule.
If you see cavity misting
Occasional light misting in the cavity during a sharp cold snap is normal and clears as the day warms. Persistent misting means warm room air is reaching the cavity, usually through a gasket that has shifted. Call us — it is an adjustment, not a fault with the glass.
Frequently asked questions
Once or twice a year is plenty. The cavity is largely sealed, so those faces stay far cleaner than the room-side ones.
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