Vertical Sliding Sash Windows — London & the Home Counties
Faithful Georgian and Victorian sash proportions in a modern, spring-balanced frame — with run-through horns, deep bottom rails, astragal bars and tilt-in sashes for cleaning. The right window for a period façade and one of the most requested styles in central London.
The run-through horn
On an authentic Georgian sash the horn is a solid extension of the stile — not a moulded stub-on. Ours are run-through the full depth of the sash and shaped with the correct ovolo profile, so the proportion reads right at three paces.
Overview
A closer look at what makes the sash windows range distinctive — the specification, the styles, the process, and the answers to the questions we get asked most.
Six-chamber uPVC vertical sliding sash profile · spiral-spring balances · argon-filled A+ glazing · through-frame or ovolo astragal bars · Yale multi-point sash locks
Authentic Period Proportions
Deep bottom rails, run-through sash horns, ovolo detailing and single or two-over-two astragal bars — proportioned from measured drawings of original Georgian and Victorian sashes.
Spring-Balanced Movement
Modern spiral-spring balances replace the traditional cord-and-weight — no rattle, no rot, and the sash stays where you put it for 25+ years.
Tilt-In for Cleaning
Both sashes tilt inward on release catches so the outside of the glass can be cleaned from inside — a necessity in London terraces without rear access.
Heritage Colours
Painswick, Chartwell Green, Cream, Anthracite Grey and Irish Oak in deep-grain foil finishes — colour-fast for 25+ years with no maintenance.
Conservation-Area Approved
Regularly accepted by conservation officers across London and the Home Counties. We prepare drawings and finish samples for your planning officer at no charge.
A+ Modern Performance
Argon-filled A+ glazing, warm-edge spacer bars and PAS 24 security locking — Georgian looks, 21st-century thermal and security performance.
Three material ranges, one configuration.
The sash configuration is available across every one of our window ranges — the material choice is yours.
Engineered to the millimetre.
Every frame we install is made to your survey sizes with the following performance envelope as standard.
- U-value (whole window)
- 0.9 – 1.4 W/m²K
- Sash size (max)
- 1.6 m wide × 2.4 m tall per sash
- Bar options
- 18mm astragal · 25mm Georgian · through-frame duplex-butt · lead-effect
- Balance
- Twin spiral-spring — no weights, no cords, no rot
- Colours
- Painswick, Chartwell Green, Cream, Anthracite, Irish Oak + full RAL
- Cleaning
- Both sashes tilt inward from inside the room
Sash Windows across London
and the Home Counties.
We install sash windows across six counties — every project surveyed, made and fitted by our in-house team. Choose your county to read local knowledge, planning notes and recent work.
See all areas coveredSash Windows — installed.
A selection of recent installations across London and the Home Counties, photographed on site.
Practical answers.
Everything homeowners ask us about sash windows — survey, lead times, guarantees and coverage.
Will a uPVC sash window be accepted in a conservation area?+
Often, yes — particularly with a timber-effect finish, deep bottom rails, run-through horns and through-frame astragal bars. Success depends on the specific conservation area and officer. We prepare drawings and finish samples at no charge to support planning applications.
Are they suitable for listed buildings?+
Sometimes — listed-building consent is at the officer's discretion. Where uPVC is refused, we can supply the same profile in painted aluminium or timber-composite. We advise honestly at survey.
How authentic do modern sash windows look?+
Very. At three paces you would not know — the giveaway on poorly detailed sash windows is thin bottom rails, missing horns and applied (rather than through-frame) glazing bars. We specify all three correctly as standard.
Do they still rattle like old sash windows?+
No. Modern spiral-spring balances and brush-pile weather seals eliminate the rattle and draught associated with original box-sash windows entirely.
What distinguishes a well-made sash window?+
Authentic proportions, deep bottom rails, run-through horns, well-balanced movement and correctly detailed glazing bars distinguish a well-made sash. We match these details to the period of the property.
Can I have double or triple glazing in a sash window?+
Yes — double glazing is standard, and triple glazing is available in a slightly deeper sash. Both keep the authentic external appearance.
Enquire about
Sash Windows.
Speak with our design team, book a home survey, and receive a fixed written quotation — all with no obligation.
Call · 020 3633 0405