Georgian to Edwardian
Secondary Glazing for Sash Window Homes
If you own a sash window homes, the window problem is nearly always the same: sash rattle, draughts and irreplaceable glass. If you own a sash-window home, secondary glazing is almost always the right answer — replacing sashes destroys character and often isn't permitted anyway.
Why sash window homes owners choose secondary glazing
The room-side unit protects fragile original glass from thermal shock and impact.
In a mid-terrace, the acoustic gain is typically 35–45 dB — enough to sleep with the window latch just cracked.
A balanced vertical slider gives you two operable sashes behind the original — with the modern seals the original never had.
Recommended: Heritage & Listed
the conservation officer's preferred upgrade
fully reversible install — no alteration to historic fabric
Historic England and most local conservation officers recommend room-side secondary glazing over replacement double glazing on protected properties — it's the only upgrade that's fully reversible.
Local reference points
- Era
- Georgian to Edwardian
- Typical window
- vertical box sashes of every era
- Top problem
- sash rattle, draughts and irreplaceable glass
- Recommended service
- Heritage & Listed
- Recommended product
- vertical sliders
- Performance
- fully reversible install — no alteration to historic fabric
Recent installs nearby
Nether Edge Grade II sash retrofit
Six original box sashes fitted with balanced vertical secondary sliders — full listed-building consent secured in six weeks.
Ecclesall Road bay-window sound retrofit
Three-panel horizontal sliders across a 3.2 m Edwardian bay — Rw measured at 47 dB post-install.
Kelham Island loft conversion
Four large steel-frame factory openings sealed with slim satin-anodised horizontal sliders. Post-install U-value 1.87 W/m²K.
Listed-building consent help — free with every quote
We draft the drawings and specifications your conservation officer needs.
Common questions
Will the install harm the original sashes?
No — the secondary system fits into the reveal, not into the sash box. The original window operates exactly as before.
Will the frame be visible from outside?
No — the entire system sits room-side of the original window. From the pavement your frontage looks unchanged.
What's the impact on natural light?
Minimal — the second pane is optically clear and slim-line frames sit within the original reveal so no daylight is lost.
Do you match the frame colour to my existing joinery?
Yes — powder-coated aluminium is available in white, black, grey, satin anodised or any of 200+ RAL colours, colour-matched on request.
Is listed-building consent needed?
In many cases no, because no historic fabric is altered. Where it is needed we supply drawings and specifications with your quote at no cost.
Next step for sash window homes owners
Send us photos of one or two windows and we'll come back with a written quote and a spec sheet you can compare against replacement double glazing.