Derry~Londonderry · County Londonderry
Sash Windows in Derry~Londonderry
Homeowners and landlords in Derry~Londonderry can get a written sash window quote that fixes the price for the joinery, glass, colour and hardware shown.
- BT48
- Guide from £1,495
uPVC sliding sash windows for homes and businesses in Derry~Londonderry
A traditional box sash hides cast-iron or lead weights inside the side boxes of the frame, connected to each sash by cords running over pulleys. Modern sash windows often use spiral or spring balances instead, which take up less depth and suit uPVC and some new timber designs without weight pockets.
Timber sash windows are usually made from engineered softwood or durable hardwoods, factory primed and finished with microporous paint that lets moisture escape. Factory finishing gives a more even coat than painting on site, but timber still needs periodic redecoration, and the interval depends on exposure and colour.
Heavy double glazed sashes need matching weights. When single glazed sashes are swapped for double glazed ones in an existing box, the old weights are usually too light, so the glazier re-weighs each sash to stop it dropping or creeping up, and checks the pulleys can carry the load.
Sash windows that run smoothly need routine care: keep the pulley wheels free of paint, wax or lightly lubricate the running channels, check the cords for fraying, and repaint timber before bare wood shows. Draught brush seals in the beads and meeting rails reduce rattles and heat loss.
What's included
- Sealing, finishing and written guarantee terms
- Survey recording mouldings, horns, bars and box condition
- Made-to-measure timber or uPVC sash windows
- Double glazed units, with safety glass where required

Derry~Londonderry at a glance
- Postcodes covered
- BT48 and the surrounding area, including Strabane, Limavady and Portstewart
- Coast
- Derry~Londonderry sits roughly 6 km from the nearest coastline, close enough that exposure on open or high ground is worth considering. Salt-laden wind and driving rain shorten the life of paint on exposed sashes, so coastal timber windows benefit from durable timbers, good factory coatings and regular inspection. Brass or stainless sash furniture resists corrosion better than plated steel near the sea.
- Daylight and sun
- In Derry~Londonderry the midwinter sun reaches about 12° above the horizon at noon, with roughly 6.9 hours of daylight, rising to about 58° and 17.1 hours in midsummer. Glazing bars and deep frames reduce daylight, so slimmer bars and high light-transmission low-E glass help north-facing rooms. Tall south-facing sashes can let in strong summer sun; the top sash can be lowered to vent warm air out at high level.
- Access and setting
- Terraced streets and conservation areas often control sash details on front elevations, so check requirements before ordering. Flats need planning permission and freeholder consent, and upper-floor sashes are usually fitted from inside, with careful protection of communal stairs and hallways.
- 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 Derry~Londonderry
| Typical job | Guide price inc VAT |
|---|---|
| uPVC sliding sash, 900 × 1500 mm | £1,495 – £1,995 |
| Timber-effect uPVC sash, 900 × 1500 mm | £1,795 – £2,295 |
| Painted timber sash, 900 × 1500 mm | £2,595 – £3,295 |
Get a guide price for your size
For replacement doors and windows in Northern Ireland, PAS 24 products are a sensible choice for security.
Choosing your sash windows
Timber box sash
Traditional weights, cords and pulleys in a box frame, made in engineered softwood or hardwood and factory painted to your colour.
Tilt-in sashes
Sashes that tilt inwards for cleaning upper-floor glass from inside, and can help provide an escape opening.
Spring-balanced timber sash
Timber sashes running on concealed spring balances, giving a slimmer frame where weight pockets are not needed or space is tight.
Sash Windows in Derry~Londonderry: questions
Will double glazed sashes be too heavy for my existing frame?
Double glazed sashes are heavier than single glazed ones, so the box frame, pulleys and weights must cope. When new sashes go into an existing box, the glazier checks the pulleys and adds or replaces weights so each sash balances. If the box is weak or rotten, a new frame is the better option, and the survey will tell you.
Should I repair or replace my sash windows?
Repair suits sashes where the timber is mostly sound and only cords, beads or small sections need attention, especially in listed or conservation properties. Replacement suits frames with widespread rot, distortion or repeated failures, or where you want double glazing and better security. A survey of each window shows which approach makes sense, and we can quote either.
What guarantee comes with new sash windows?
Manufacturer guarantees apply to the joinery, finish, sealed units and hardware, and the terms are confirmed in writing. Cover on the paint finish often depends on regular maintenance, so check the conditions. Guarantee terms for the installation are set out in writing with your quote, so you know what is covered before agreeing to go ahead.
What maintenance do timber sash windows need?
Timber sash windows need periodic repainting, how often depends on exposure, orientation and colour, plus routine checks of cords, pulleys and seals. Keep paint off the running surfaces, clean the sills and touch up chips before water gets in. Factory-finished timber lasts longer between coats than site-painted joinery, but still benefits from yearly inspection.
Do you cover Derry~Londonderry for sash windows?
Yes. We can quote for sash windows across Derry~Londonderry and the surrounding County Londonderry area, including postcode districts BT48, and nearby Strabane, Limavady and Portstewart. Start with your postcode on the quote form and a glazier will arrange a free survey before giving you a written quote.
More glazing in Derry~Londonderry
Get a written quote in Derry~Londonderry
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