Coulsdon · Greater London
Sash Windows in Coulsdon
Period homes in Coulsdon can keep the look of traditional sliding sashes while gaining double glazing, smoother running and stronger locks from our made-to-measure sash windows.
- CR5
- CR8
- SM7
- Guide from £1,495
About timber sash windows in Coulsdon
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.
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.
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.
A sliding sash only opens to about half its frame height, which can make an escape window harder to achieve. In England, Approved Document B guidance calls for at least 0.33 m² clear opening, 450mm high and wide, so tilt-in or side-hung escape sashes are sometimes specified for upper floors.
What's included
- Double glazed units, with safety glass where required
- Sealing, finishing and written guarantee terms
- Survey recording mouldings, horns, bars and box condition
- Removal of old sashes or frames and disposal

Coulsdon at a glance
- Postcodes covered
- CR5, CR8, SM7 and the surrounding area, including Purley, Banstead and Wallington
- Coast
- Coulsdon is well inland, around 38 km from the nearest coast, so salt exposure is not usually a factor.
- Daylight and sun
- In Coulsdon 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
- Older rural houses often have sash openings that are out of square, with soft stone or lime plaster around them, so each window is measured individually and fitted gently. Exposed sites benefit from draught seals and robust weatherboards on the bottom sash.
- 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 Coulsdon
| 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.
Options to choose between
Replacement sashes only
New double glazed sashes fitted into your existing sound box frame, keeping original linings, architraves and plasterwork.
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.
Heritage glass options
Slim double glazing, low-E coatings and textured glass that looks like old cylinder glass for sensitive elevations.
Sash Windows in Coulsdon: 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.
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.
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.
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.
Do you cover Coulsdon for sash windows?
Yes. We can quote for sash windows across Coulsdon and the surrounding Greater London area, including postcode districts CR5, CR8 and SM7, and nearby Purley, Banstead and Wallington. 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 Coulsdon
Free survey for new glazing, clear guide prices and one point of contact for every glazing job.