Windows
Sash windows
A uPVC vertical sliding sash keeps the look of a traditional box sash, with two sashes sliding past each other, run-through horns and a deep bottom rail. It drops the rattles, draughts and repainting that come with old timber.
See all 6 layoutsModern sash windows run on spiral or constant-force balances rather than weights and cords, so they slide smoothly and stay where you leave them. On most systems the sashes tilt inwards, so you can clean both sides of the glass from inside.
We match the details of your original windows, including the glazing bar layout, horn style, bottom-rail depth and colour. Measuring matters here. In many older houses the frame sits behind a rebate in the brickwork, so we measure from inside and out before we quote.
Be realistic about the trade-offs. uPVC sashes have thicker frames and meeting rails than slim timber ones, and a sliding sash does not usually seal as tightly as a compression-sealed casement. In a listed building, replacement in uPVC is rarely allowed, so check with your local authority before booking a survey.
6 standard layouts
The layouts we fit most in UK homes. Every one is made to measure, and you choose the opening side, colour and glass. Need something different? Tell us and we’ll draw it for you.
SW-04Popular
Six over six
The classic Georgian pattern: six panes in each sash.
Quote this layout: Six over sixSW-05
Six over one
Six panes in the top sash over a plain bottom sash.
Quote this layout: Six over oneSW-06
Eight over eight
Eight panes in each sash, for wider openings.
Quote this layout: Eight over eightDrawings are viewed from outside and are not to scale. Dashed lines meet at the hinge side. Sizes are typical starting points; we measure every opening at survey.
Why choose sash windows
Authentic proportions
Run-through horns, deep bottom rails and Georgian bar patterns.
Tilt-in cleaning
Sashes tilt inwards so you can clean the outside glass from indoors.
Balanced sashes
Spiral or constant-force balances replace weights and cords.
Fewer draughts
Brush pile and gasket seals stop the rattle of old box sashes.
At a glance
Exact figures depend on the system and options you choose. We confirm them on your written quote.
| Operation | Vertical sliding; sashes tilt in for cleaning on most systems |
|---|---|
| Glazing | Double glazed as standard. Triple glazing available on request |
| Energy | Meets Building Regulations Part L for replacement windows (U-value 1.4 W/m²K or better, or WER band B or above). A-rated options available |
| Ventilation | Trickle vents fitted where Part F requires them, including wherever the old windows had them |
| Safety glass | Toughened or laminated glass in critical locations, including any pane within 800 mm of the floor (Part K) |
| Colours | White, cream, woodgrain foils and solid colours including anthracite grey (RAL 7016), black and Chartwell green |
| Security | Cam locks, sash stops or restrictors; PAS 24 tested options available |
About sash windows
Can uPVC sash windows go in a listed building?
Usually not. Listed building consent is needed for any window change and is rarely given for uPVC. Speak to your local authority conservation officer before you go further.
Will they still have trickle vents?
If your existing windows have trickle vents, Part F requires the replacements to have them too. Slim vents can be fitted in the head of the frame, where they are least noticeable.
Can a sash window be an escape window?
It can, but it is harder. Only one sash opens at a time, so the clear opening is roughly half the window. An escape window needs at least 0.33 m² clear, at least 450 mm wide and 450 mm high, with the bottom of the opening no more than 1,100 mm above the floor. We check the size at survey and suggest options if it falls short.
Should I restore my timber sashes instead?
If the timber is mostly sound, or the house is listed, restoration by a timber sash specialist may be the better route. uPVC makes most sense where the frames are rotten or you want to stop repainting.
Similar styles
Flush casement windows
Sashes sit level with the frame, like timber joinery. Woodgrain and heritage colours.
- 6 layouts
- Sits flush
- Heritage colours
- Woodgrain
Bay & bow windows
Three to six facets that catch light from several sides. Structure checked at survey.
- 5 layouts
- 3–6 facets
- Bay support poles
Casement windows
Hinged and fixed panes in almost any layout. The standard window for most UK houses.
- 34 layouts
- Side-hung
- Top-hung
- Fixed lights
Free survey · written quote · no obligation
Get a price for sash windows.
Send rough sizes and a few photos for an estimate. Or book a free survey and we’ll measure everything ourselves.