Derby · Derbyshire
Sash Windows in Derby
Our glaziers survey sash windows across Derby, recording mouldings, horns and glazing bars so the new windows suit the house and any conservation requirements.
- DE1
- DE22
- DE23
- Guide from £1,495
Sash windows in Derby: what to know
Security on sash windows comes from keyed sash locks at the meeting rails, sash stops that limit the opening for ventilation and child safety, laminated glass, and close-fitting staff and parting beads. Ground-floor sashes in older houses are often the weakest point, so locks are worth upgrading during replacement.
In England, Approved Document L allows an alternative where a window must keep a building's character: a centre-pane U-value no worse than 1.2 W/m²K, or single glazing supplemented by low-E secondary glazing. Otherwise a replacement should meet 1.4 W/m²K or Window Energy Rating band B.
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 can be supplied as complete new frames, or as new double glazed sashes fitted into an existing sound box frame. Keeping the box retains original linings and architraves and reduces disturbance to plaster, but only works when the frame is free of rot and still square.
What you get
- Removal of old sashes or frames and disposal
- Weights or balances set for smooth, even sliding
- Survey recording mouldings, horns, bars and box condition
- Sealing, finishing and written guarantee terms

About Derby for this job
- Postcodes covered
- DE1, DE22, DE23 and the surrounding area, including Belper, Ilkeston and Heanor
- Coast
- Derby is well inland, around 97 km from the nearest coast, so salt exposure is not usually a factor.
- Daylight and sun
- In Derby the midwinter sun reaches about 14° above the horizon at noon, with roughly 7.3 hours of daylight, rising to about 60° and 16.7 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 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 Derby
| 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
Replacing windows and doors with similar ones is usually permitted development for houses in England. Flats, listed buildings and homes in conservation areas or covered by an Article 4 direction can need permission, so check with the council first.
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.
uPVC sliding sash
Low-maintenance uPVC frames with sculpted profiles and optional woodgrain foils, suited to homes where planning rules allow uPVC.
Heritage glass options
Slim double glazing, low-E coatings and textured glass that looks like old cylinder glass for sensitive elevations.
Sash Windows in Derby: questions
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 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.
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.
Do sash windows have to meet building regulations?
Yes. Replacement windows are controlled under building regulations across the UK, and the detail differs between nations. In England, the work can be self-certified by an installer registered with a competent person scheme or approved by building control. Energy, ventilation, safety glazing and escape all apply, though listed buildings may meet some standards only where reasonably practicable.
Do you cover Derby for sash windows?
Yes. We can quote for sash windows across Derby and the surrounding Derbyshire area, including postcode districts DE1, DE22 and DE23, and nearby Belper, Ilkeston and Heanor. 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 Derby
Free survey for new glazing, clear guide prices and one point of contact for every glazing job.