Coleraine · County Londonderry
Secondary Glazing in Coleraine
Single-glazed sash windows in Coleraine can stay as they are, with vertical sliding secondary glazing fitted inside to reduce draughts and cold.
- BT52
- BT55
- Guide from £465
Coleraine: secondary glazing listed buildings
Slim aluminium frames are designed to sit within the window reveal and line up with the original glazing bars or meeting rails. Matching sightlines keeps the secondary unit discreet from outside and inside, which matters for period homes and conservation areas.
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.
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.
Condensation in the gap between the two windows is reduced by making the secondary unit the more airtight of the two. The original window should not be fully sealed, so any moisture that gets into the cavity can escape outside rather than being trapped against the glass.
What a typical job includes
- Written quote fixing the price for the specification
- Made-to-measure slim aluminium frames and glass
- Advice on opening style, glass and fire escape
- Survey of each window, reveal depth and sightlines

Local details for Coleraine
- Postcodes covered
- BT52, BT55 and the surrounding area, including Portstewart, Ballymoney and Limavady
- Coast
- Coleraine sits roughly 6 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 Coleraine the midwinter sun reaches about 11° above the horizon at noon, with roughly 6.9 hours of daylight, rising to about 58° and 17.1 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 Coleraine
| 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
Where a window provides an escape route, its replacement in Northern Ireland should give at least the same escape opening as before.
What you can choose
Vertical sliding
Panels slide up and down, with meeting rails aligned to sash windows so the secondary unit is discreet from inside and outside.
Lift-out panel
A lightweight panel that lifts out of its frame, for windows rarely opened, giving a slim and economical secondary unit.
Low-E glass
Coated glass that reflects heat back into the room, improving insulation when the original window is single glazed.
Secondary Glazing in Coleraine: 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.
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.
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.
Do you cover Coleraine for secondary glazing?
Yes. We can quote for secondary glazing across Coleraine and the surrounding County Londonderry area, including postcode districts BT52 and BT55, and nearby Portstewart, Ballymoney and Limavady. 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 Coleraine
Free survey for new glazing, clear guide prices and one point of contact for every glazing job.