Kensington · Greater London
Sash Windows in Kensington
We cover Kensington and the rest of Greater London for sash window replacement, from one rotten bay sash to a full set for a Victorian or Georgian house.
- SW3
- SW5
- SW7
- SW10
- W8
- W10
- Guide from £1,495
About timber sash windows in Kensington
Trickle vents can be fitted discreetly in the head of a sash frame or the top rail. In England, Approved Document F expects ventilation after window replacement to be no worse than before, although listed buildings and conservation areas may meet it only where reasonably practicable, agreed with building control.
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.
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.
What a typical job includes
- Double glazed units, with safety glass where required
- Sealing, finishing and written guarantee terms
- Removal of old sashes or frames and disposal
- Weights or balances set for smooth, even sliding
Working in Kensington
- Postcodes covered
- SW3, SW5, SW7, SW10, W8, W10, W11 and the surrounding area, including Shepherds Bush, Hammersmith and Chelsea
- Coast
- Kensington is well inland, around 39 km from the nearest coast, so salt exposure is not usually a factor.
- Daylight and sun
- In Kensington 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. 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 Kensington
| 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
Approved Document F covers ventilation. Replacing windows should not leave a room with worse background ventilation than before, which is why replacement windows often include trickle vents.
Specification choices
uPVC sliding sash
Low-maintenance uPVC frames with sculpted profiles and optional woodgrain foils, suited to homes where planning rules allow uPVC.
Glazing bar patterns
Two over two, six over six or other bar layouts, as true divisions or bars bonded to the glass faces.
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 Kensington: questions
Are uPVC sash windows allowed in conservation areas?
It depends on the council. Some conservation areas and Article 4 directions require timber on front elevations, while others accept well-detailed uPVC sashes with sculpted profiles and run-through horns. Listed buildings almost always need timber. Check your council's guidance or ask the planning department before choosing uPVC, because removing unauthorised windows later is costly.
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.
Can I have double glazed sash windows in a listed building?
Sometimes, but listed building consent is needed for significant works, and some councils will only accept repair of the original windows or slim double glazing with matching details. Secondary glazing is often accepted where new windows are not. Speak to your council's conservation officer before ordering; we can provide drawings and specifications to support an application.
How secure are sash windows?
New sash windows can be secure when fitted with keyed locks at the meeting rails, sash stops, laminated glass and tight-fitting beads. Older sashes often rely on a single catch, which is easily forced. Upgrading ground-floor and easily reached windows first makes sense, and the glazier can recommend locks that suit the sash and frame.
Do you cover Kensington for sash windows?
Yes. We can quote for sash windows across Kensington and the surrounding Greater London area, including postcode districts SW3, SW5, SW7, SW10 and W8, and nearby Shepherds Bush, Hammersmith and Chelsea. 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 Kensington
Free survey for new glazing, clear guide prices and one point of contact for every glazing job.