Hertfordshire · England
Secondary Glazing in Hertfordshire
Where planning or lease rules limit changes to the outside, secondary glazing in Hertfordshire offers an internal option that can be removed later.
- Guide from £465
- 18 towns covered
- Postcode areas AL, CM, EN, HP, SG, WD
Secondary glazing listed buildings for homes and businesses in Hertfordshire
If an existing window is relied on for escape in a fire, the secondary glazing in front of it must open easily and give enough clear opening. The surveyor checks which windows are escape windows, so the opening style and catches do not block a way out.
Owners of listed buildings should seek listed building consent before installing secondary glazing, as the requirements depend on the building and the council. Secondary glazing is often seen as a minimal, reversible change, but carrying out works that need consent without it is a criminal offence.
Secondary glazing can also add security, because an intruder would have to break through two separate windows. Laminated glass and locking catches on the secondary unit add further resistance, which is useful for ground-floor and basement windows in period properties.
Glass for secondary glazing is heavy, so the frames need firm fixings into the reveal or a supporting sub-frame. The surveyor checks that plaster, timber linings and window boards are sound enough to carry the weight, and allows for any packing needed in uneven reveals.

Towns we cover for secondary glazing in Hertfordshire
Choose your town for local details, nearby areas and the postcode districts we cover.
What applies in Hertfordshire
Approved Document K requires safety glass in critical locations in England: glazing in doors and in side panels within 300 mm of a door, up to 1500 mm above floor level, and any glazing in walls or partitions up to 800 mm above floor level.
Approved Document B covers escape windows. Where an existing window is an escape route, typically in first-floor bedrooms, its replacement should give at least the same escape opening as before.
Hertfordshire is inland, around 39 km from the nearest coast at its closest point, so salt exposure is rarely a factor.
Rural cottages and period homes often have single-glazed timber windows that cannot easily be replaced. Secondary glazing reduces draughts and heat loss in exposed locations, and the surveyor allows for uneven reveals and older plaster when fixing frames.
Guide prices
| Typical job | Guide price inc VAT |
|---|---|
| Slider, 900 × 1200 mm | £465 – £595 |
| Slider, 1200 × 1600 mm | £665 – £845 |
| Acoustic glass, 1000 × 1400 mm | £675 – £865 |
Choosing your secondary glazing
Vertical sliding
Panels slide up and down, with meeting rails aligned to sash windows so the secondary unit is discreet from inside and outside.
Acoustic laminated glass
Laminated glass with a sound-dampening interlayer, combined with a generous cavity, for properties affected by traffic, rail or aircraft noise.
Low-E glass
Coated glass that reflects heat back into the room, improving insulation when the original window is single glazed.
Lift-out panel
A lightweight panel that lifts out of its frame, for windows rarely opened, giving a slim and economical secondary unit.
Secondary Glazing in Hertfordshire: questions
Is secondary glazing suitable for rented homes and flats?
Yes. Secondary glazing is fitted inside, so it often avoids the external changes that leases, freeholders or planning rules restrict. It can be removed later with limited making good. Leaseholders should still check their lease for any rules on internal alterations, and landlords should check escape routes are not affected.
Is secondary glazing as good as double glazing?
It depends on the goal. For noise, secondary glazing is often more effective, because the wider gap between the two windows reduces sound better than the narrow cavity of a sealed unit. For heat, a well-sealed secondary unit with low-E glass significantly improves a single-glazed window. It also keeps original windows, which matters in listed buildings.
Which opening style should I choose?
Choose based on how you use the window. Vertical sliders suit sash windows and keep meeting rails aligned. Horizontal sliders suit wide windows. Hinged panels give full access for cleaning and escape. Lift-out and fixed panels suit windows that are rarely or never opened, and give the tightest seal for noise.
How do I clean and look after secondary glazing?
Open or remove the panels as designed, then clean the glass with mild soapy water and a soft cloth. Wipe the aluminium frames and runners, and keep tracks free of dust so panels slide smoothly. Check seals and catches occasionally. Avoid abrasive cleaners, which can scratch coated glass.
Which parts of Hertfordshire do you cover for secondary glazing?
We cover the whole of Hertfordshire, including Watford, Hemel Hempstead, Stevenage, St Albans and Welwyn Garden City, and postcode areas AL, CM, EN, HP, SG, WD. Building rules for secondary glazing here follow the regulations for England. Enter your postcode on the quote form and we will confirm cover; then a glazier will arrange a free survey before giving you a written quote.
Other glazing services in Hertfordshire
- Replacement Glass in Hertfordshire
- Misted Glass Repair in Hertfordshire
- Emergency Glazing in Hertfordshire
- Safety Glass in Hertfordshire
- Window Repairs in Hertfordshire
- Window Film in Hertfordshire
- uPVC Windows in Hertfordshire
- Aluminium Windows in Hertfordshire
- Sash Windows in Hertfordshire
- Composite Doors in Hertfordshire
- Bifold Doors in Hertfordshire
- Sliding Doors in Hertfordshire
- Roof Lanterns in Hertfordshire
- Glass Balustrades in Hertfordshire
- Frameless Glass in Hertfordshire
- Shower Screens in Hertfordshire
- Glass Splashbacks in Hertfordshire
- Bespoke Mirrors in Hertfordshire
- Glass Roofs in Hertfordshire
- Shopfront Glazing in Hertfordshire
- Curtain Walling in Hertfordshire
- Glass Partitions in Hertfordshire
- Property Glazing in Hertfordshire
All glazing in Hertfordshire · Secondary Glazing across the UK
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