Clapham · Greater London
Sash Windows in Clapham
Period homes in Clapham can keep the look of traditional sliding sashes while gaining double glazing, smoother running and stronger locks from our made-to-measure sash windows.
- SW4
- SW8
- SW11
- Guide from £1,495
About double glazed sash windows in Clapham
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.
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.
Many Victorian and Georgian sashes reach low to the floor. In England, Approved Document K treats glazing within 800mm of floor level as a critical location, so the lower panes of tall sash windows usually need toughened or laminated safety glass, which should be permanently marked.
What you get
- Sealing, finishing and written guarantee terms
- Survey recording mouldings, horns, bars and box condition
- Double glazed units, with safety glass where required
- Removal of old sashes or frames and disposal
About Clapham for this job
- Postcodes covered
- SW4, SW8, SW11 and the surrounding area, including Brixton, Chelsea and Streatham
- Coast
- Clapham is well inland, around 35 km from the nearest coast, so salt exposure is not usually a factor.
- Daylight and sun
- In Clapham 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 Clapham
| 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.
What you can choose
Heritage glass options
Slim double glazing, low-E coatings and textured glass that looks like old cylinder glass for sensitive elevations.
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.
Sash Windows in Clapham: 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.
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.
How much do sash windows cost?
The cost of sash windows depends on size, material, whether you replace the whole frame or only the sashes, the glazing bar pattern, the glass and the finishing details such as horns and mouldings. Timber usually costs more than uPVC, and listed building work costs more again. See the guide prices for typical ranges; the written quote fixes your price.
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 Clapham for sash windows?
Yes. We can quote for sash windows across Clapham and the surrounding Greater London area, including postcode districts SW4, SW8 and SW11, and nearby Brixton, Chelsea and Streatham. 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 Clapham
Free survey for new glazing, clear guide prices and one point of contact for every glazing job.