Carshalton · Greater London
Secondary Glazing in Carshalton
Our surveyors can measure windows across Carshalton for secondary glazing, checking reveal depth, opening style and fire escape needs before quoting.
- SM5
- SM1
- SM6
- Guide from £465
Internal secondary windows in Carshalton: what to know
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.
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.
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.
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.
Included as standard
- Survey of each window, reveal depth and sightlines
- Made-to-measure slim aluminium frames and glass
- Removal of packaging and cleaning of new glass
- Advice on opening style, glass and fire escape

Working in Carshalton
- Postcodes covered
- SM5, SM1, SM6 and the surrounding area, including Wallington, Sutton and Mitcham
- Coast
- Carshalton is well inland, around 38 km from the nearest coast, so salt exposure is not usually a factor.
- Daylight and sun
- In Carshalton 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 Carshalton
| 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 L sets the minimum energy performance for replacement windows and doors in existing homes in England: a U-value of 1.4 W/m²K, or Window Energy Rating band B for windows; doors can instead meet a Door Set Energy Rating (band B, or band C for doors more than 60% glazed); rooflights need 2.2 W/m²K.
Options to choose between
Lift-out panel
A lightweight panel that lifts out of its frame, for windows rarely opened, giving a slim and economical secondary unit.
Fixed panel
A non-opening unit for windows never opened, giving the most airtight seal for noise and draught reduction.
Low-E glass
Coated glass that reflects heat back into the room, improving insulation when the original window is single glazed.
Secondary Glazing in Carshalton: questions
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.
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.
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.
Will secondary glazing cause condensation?
It can, if the original window is sealed tighter than the secondary unit, because warm, moist room air then gets trapped in the cavity. The secondary unit should be the more airtight of the two, and the original window should not be fully sealed. Opening the secondary panel lets room air into the cavity, so close it again afterwards.
Do you cover Carshalton for secondary glazing?
Yes. We can quote for secondary glazing across Carshalton and the surrounding Greater London area, including postcode districts SM5, SM1 and SM6, and nearby Wallington, Sutton and Mitcham. Start with your postcode on the quote form and a glazier will arrange a free survey before giving you a written quote.
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