Dundonald · County Down
Secondary Glazing in Dundonald
Our surveyors can measure windows across Dundonald for secondary glazing, checking reveal depth, opening style and fire escape needs before quoting.
- BT16
- Guide from £465
Dundonald: 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.
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.
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.
What you get
- Made-to-measure slim aluminium frames and glass
- Fitting, sealing and checking every opening panel
- Survey of each window, reveal depth and sightlines
- Removal of packaging and cleaning of new glass

Dundonald at a glance
- Postcodes covered
- BT16 and the surrounding area, including Holywood, Comber and Castlereagh
- Coast
- Dundonald sits roughly 7 km from the nearest coastline, close enough that exposure on open or high ground is worth considering. Coastal properties often have older windows exposed to wind-driven rain and draughts. Secondary glazing adds a sealed inner layer that reduces draughts and cold, while the original window keeps out the weather and its condition is protected from inside.
- Daylight and sun
- In Dundonald the midwinter sun reaches about 12° above the horizon at noon, with roughly 7.0 hours of daylight, rising to about 59° and 17.0 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 Northern Ireland
- Technical Booklet V covers safety glazing in Northern Ireland, including glass in and around doors and low-level glazing where people could walk into it.
Guide prices in Dundonald
| 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 Northern Ireland need listed building consent for most changes to historic windows.
Choosing your secondary glazing
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.
Horizontal sliding
Panels slide sideways, suiting wide casement windows and openings where you need regular access for cleaning or ventilation.
Secondary Glazing in Dundonald: 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.
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.
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.
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 Dundonald for secondary glazing?
Yes. We can quote for secondary glazing across Dundonald and the surrounding County Down area, including postcode districts BT16, and nearby Holywood, Comber and Castlereagh. 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 Dundonald
Free survey for new glazing, clear guide prices and one point of contact for every glazing job.