Sevenoaks · Kent
Secondary Glazing in Sevenoaks
Period homes in Sevenoaks can keep their character and gain comfort with discreet secondary glazing fitted inside the existing window reveals.
- TN13
- Guide from £465
About secondary glazing in Sevenoaks
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.
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.
Opening styles include vertical sliders that line up with sash window meeting rails, horizontal sliders for wide openings, hinged casements, lift-out panels for windows that are rarely opened, and fixed panes. The choice depends on how you use the window, cleaning access and fire escape needs.
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.
What you get
- Made-to-measure slim aluminium frames and glass
- Fitting, sealing and checking every opening panel
- Removal of packaging and cleaning of new glass
- Survey of each window, reveal depth and sightlines

Sevenoaks at a glance
- Postcodes covered
- TN13 and the surrounding area, including Tonbridge, Orpington and Swanley
- Coast
- Sevenoaks is well inland, around 23 km from the nearest coast, so salt exposure is not usually a factor.
- Daylight and sun
- In Sevenoaks 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
- 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.
- 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 Sevenoaks
| 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
Listed buildings in England need listed building consent for most changes to historic windows or glass, and conservation areas can restrict changes visible from the street. Speak to the council's conservation officer before ordering.
Specification choices
Vertical sliding
Panels slide up and down, with meeting rails aligned to sash windows so the secondary unit is discreet from inside and outside.
Horizontal sliding
Panels slide sideways, suiting wide casement windows and openings where you need regular access for cleaning or ventilation.
Fixed panel
A non-opening unit for windows never opened, giving the most airtight seal for noise and draught reduction.
Secondary Glazing in Sevenoaks: questions
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.
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.
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.
Do you cover Sevenoaks for secondary glazing?
Yes. We can quote for secondary glazing across Sevenoaks and the surrounding Kent area, including postcode districts TN13, and nearby Tonbridge, Orpington and Swanley. 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 Sevenoaks
Free survey for new glazing, clear guide prices and one point of contact for every glazing job.