1918–1939
Secondary Glazing for 1930s Semi
If you own a 1930s semi, the window problem is nearly always the same: steel frames bleeding heat and rusting shut. 1930s steel-frame casements are one of the worst performers in the UK housing stock — the frames conduct heat straight through and condense water on the room-side.
Why 1930s semi owners choose secondary glazing
Lift-out panels are the cheapest way to seal the top-light Crittalls that never open in normal use.
Where the original steel frame is Grade II listed we specify slim satin-anodised profiles that match the original sightlines.
A hinged secondary unit set inside the reveal isolates the steel frame completely, so the cold-metal downdraught disappears in a single afternoon's install.
Recommended: Condensation Control
eliminate the cold-glass surface that draws condensation
warmer room-side glass at ambient temperatures 4–6°C higher
Condensation forms when warm, moist room air hits cold glass — the fix is to raise the room-side glass temperature, which a secondary pane and the sealed cavity does immediately.
Local reference points
- Era
- 1918–1939
- Typical window
- steel Crittall-style casements
- Top problem
- steel frames bleeding heat and rusting shut
- Recommended service
- Condensation Control
- Recommended product
- lift out windows
- Performance
- warmer room-side glass at ambient temperatures 4–6°C higher
Recent installs nearby
A61 corridor 1930s semi
Front-facing Crittall casements enclosed with hinged secondary units. Traffic noise reduced from disruptive to background.
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.
Book an on-site survey
We measure and template every opening — no per-square-metre guesswork.
Common questions
Will condensation form between the two panes?
The cavity is ventilated outwards to the primary window so any residual moisture escapes — the room-side stays sealed and warmer.
Will it help with condensation on my sash windows?
Almost always — the room-side pane raises the surface temperature of the glass you touch, which stops warm interior air condensing.
How much noise reduction can I realistically expect?
With a 100 mm cavity and 6.4 mm laminated secondary glass we routinely measure 40–47 dB Rw — enough to drop main-road traffic to a soft background hum.
Will secondary glazing stop conversation-level noise from a neighbour?
Yes — mid-frequency speech is exactly what a laminated secondary pane damps hardest. We'd typically spec 6.8 mm on the secondary and keep the primary as-is.
Does it help with train and tram rumble?
It's very effective — the low-frequency energy is absorbed by the air-gap decoupling. A mismatched pane thickness widens the acoustic dip that train rumble usually punches through.
Next step for 1930s semi 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.