Can you fit secondary glazing to French doors?

Yes. Full-height sliding or double-leaf hinged panels are fitted inside the reveal, up to 2.4m tall. The original doors stay fully operable — the secondary panels slide or swing clear for garden access.

Will there be a step or trip hazard at the threshold?

No. Sliding systems use a low-profile track under 12mm proud of finished floor level with a combination brush and compression seal, so the sound path is closed without a raised lip.

How much noise reduction can French doors achieve?

Up to 50dB with 10.8mm acoustic laminate. That is slightly below a window installation because the opening is larger and the threshold detail is inherently more difficult to seal.

What does secondary glazing for French doors cost?

From £890 for a standard pair up to 1.8m wide with 6.4mm acoustic laminate. Wide four-panel patio sets start at £1,380.

Secondary Glazing for French Doors

Full-height panels that keep the doors in daily use.

Get a fixed quote 0207 060 1572

50dB

Achievable reduction

2.4m

Max panel height

£890

From, per door set

Full

Door access retained

French doors are a large, thin, poorly sealed acoustic weak point — often the largest single opening in a London garden flat or rear extension. Original timber pairs typically leak badly at the central meeting stile and along the threshold.

Secondary glazing for French doors uses full-height sliding or double-leaf hinged panels set inside the reveal. The doors behind stay fully operable: slide or swing the secondary panels clear and use the garden as normal.

Sliding or double-leaf hinged?

Sliding is the usual choice on doors in daily use — panels park to one side and stay there through the summer. Double-leaf hinged units seal better and suit doors that are mainly used in warmer months, or where a slider track at threshold level would be a trip hazard.

Sliding: 2-4 full-height panels, easiest daily access
Double-leaf hinged: best seal, clears the opening fully
Lift-out: cheapest, for doors used seasonally only
Low-profile threshold track available on sliding systems

Threshold and floor detailing

Getting the bottom detail right matters both acoustically and practically. We use a low-profile track that sits under 12mm proud of finished floor level, with a brush-and-compression combination seal so the sound path under the panel is closed without creating a lip you catch a toe on.

Light, glazing bars and sightlines

Full-height panels are visually significant, so sightlines are kept to 25mm and frames are colour-matched to the doors. Where the original doors have glazing bars, panel divisions are set to align with them so the two layers read as one.

French door specification

Panel height: Up to 2.4m
Systems: Sliding (2-4 panel), double-leaf hinged, lift-out
Threshold: Low-profile track under 12mm with combination seal
Glass: 6.4mm or 10.8mm acoustic laminate; toughened where required
Noise reduction: Up to 50dB
Sightlines: 25mm, aligned to existing glazing bars

Pricing guide

Specification	Price	Notes
Standard French door pair, 6.4mm	from £890	Up to 1.8m wide
Wide patio set, 4 panel sliding	from £1,380	Up to 2.7m wide
10.8mm acoustic laminate upgrade	+£210-£320	Per door set
Toughened safety glass	+£90	Where required by Part K

All prices supplied and fitted in London, inclusive of survey and 25-year warranty. See the full secondary glazing price list.

Case study: Garden flat French doors in Camden

Camden, NW1

Problem: Rear doors onto a shared garden backing a pub terrace; 54dB in the living room until closing time.

Solution: Three-panel full-height sliding system in 10.8mm laminate with a low-profile threshold track.

Result: 24dB reduction, and the doors are still opened daily onto the garden.

Frequently asked questions

Get a fixed quote for secondary glazing for french doors

Free London survey, measured dB assessment and a written specification within 48 hours.

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