Finchley · Greater London
Secondary Glazing in Finchley
Single-glazed sash windows in Finchley can stay as they are, with vertical sliding secondary glazing fitted inside to reduce draughts and cold.
- N3
- N12
- N2
- Guide from £465
Finchley: secondary glazing for sash windows
The price of secondary glazing depends on the size and number of windows, the opening style, the glass specification, any shaped or arched heads, reveal depth and condition, and access. Acoustic laminated glass and shaped frames cost more than standard clear glass in rectangular frames.
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.
For noise reduction, the size of the air gap between the original window and the secondary unit matters a great deal, and a wider cavity generally performs better. Acoustic laminated glass and well-sealed frames improve results further, especially against traffic, rail and aircraft noise.
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.
Included as standard
- Made-to-measure slim aluminium frames and glass
- Advice on opening style, glass and fire escape
- Survey of each window, reveal depth and sightlines
- Written quote fixing the price for the specification

Working in Finchley
- Postcodes covered
- N3, N12, N2 and the surrounding area, including Muswell Hill, Cricklewood and Wood Green
- Coast
- Finchley is well inland, around 42 km from the nearest coast, so salt exposure is not usually a factor.
- Daylight and sun
- In Finchley the midwinter sun reaches about 15° above the horizon at noon, with roughly 7.6 hours of daylight, rising to about 62° and 16.4 hours in midsummer. Secondary glazing adds an extra layer of glass, which slightly reduces daylight. Low-iron or clear low-E glass keeps light loss to a minimum, while on sunny elevations solar control glass can help reduce overheating in rooms with large windows.
- Access and setting
- In city centres and busy streets, acoustic secondary glazing is a common response to traffic, rail and nightlife noise. Flats, listed buildings and conservation areas often limit external changes, which makes internal secondary glazing a practical option.
- Rules in England
- 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.
Guide prices in Finchley
| 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 |
Get a guide price for your size
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.
Specification choices
Lift-out panel
A lightweight panel that lifts out of its frame, for windows rarely opened, giving a slim and economical secondary unit.
Horizontal sliding
Panels slide sideways, suiting wide casement windows and openings where you need regular access for cleaning or ventilation.
Acoustic laminated glass
Laminated glass with a sound-dampening interlayer, combined with a generous cavity, for properties affected by traffic, rail or aircraft noise.
Secondary Glazing in Finchley: questions
Do I need permission for secondary glazing on a listed building?
You should seek listed building consent from the council's planning department before installing secondary glazing on a listed building. Secondary glazing is often seen as a reversible, low-impact change, but consent requirements depend on the building. Carrying out works that need consent without it is a criminal offence. If your home is not listed but is in a conservation area, check with the council if you are unsure.
How much noise does secondary glazing block?
Results depend on the size of the gap between the windows, the glass type and thickness, the seals and the original window. A larger cavity and acoustic laminated glass give the strongest improvement. The survey checks reveal depth and noise sources, so the specification can be tailored to the noise you are dealing with.
How much does secondary glazing cost?
The cost depends on the size and number of windows, the opening style, the type of glass, any arched or shaped heads, reveal depth and access. Acoustic and low-E glass cost more than standard clear glass, and shaped frames need more work. See the guide prices for typical windows, then get a written quote after the survey.
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.
Do you cover Finchley for secondary glazing?
Yes. We can quote for secondary glazing across Finchley and the surrounding Greater London area, including postcode districts N3, N12 and N2, and nearby Muswell Hill, Cricklewood and Wood Green. Start with your postcode on the quote form and a glazier will arrange a free survey before giving you a written quote.
Get a written quote in Finchley
Free survey for new glazing, clear guide prices and one point of contact for every glazing job.