Timber Casement Windows for London Properties
Casement windows are the most versatile timber window type. They suit everything from contemporary new builds to Arts and Crafts cottages, 1930s semis, and modern extensions on period properties. Unlike sash windows, casement windows hinge outward (or inward) and offer unrestricted ventilation — the entire window aperture opens.
At Prime Sash Windows, we manufacture bespoke timber casement windows in over 20 configurations. Single light, double light, triple light. With or without fanlights. Side-hung, top-hung, or fixed. Every window is made to your exact dimensions in engineered Accoya or hardwood, spray-finished in any colour.
Casement Window Styles
Flush Casement
The sash sits flush with the outer frame when closed — a clean, traditional appearance suited to conservation areas and period properties.
Stormproof Casement
The sash overlaps the frame, creating a superior weather seal. The most popular choice for new builds and extensions.
Multi-Light Casement
Two, three, or four lights in a single frame. Mix opening and fixed sections to suit ventilation and budget requirements.
Casement with Fanlight
A top-hung opening light above the main casement. Traditional appearance with excellent ventilation — the fanlight can remain open in rain.
Casement Window Prices in London
Prices depend on size, number of opening lights, glazing, and finish. Below is a guide for standard stormproof casement windows with double glazing and a factory-applied paint finish.
| Configuration | Double Glazed | Triple Glazed |
|---|---|---|
| Single light (600 × 900mm) | From £850 | From £1,050 |
| Double light (1200 × 1200mm) | From £1,400 | From £1,750 |
| Triple light (1800 × 1200mm) | From £2,000 | From £2,500 |
| Double light + fanlight (1200 × 1500mm) | From £1,800 | From £2,250 |
All prices include PAS24 enhanced security hardware, factory-applied paint in any RAL or Farrow & Ball colour, and fully sealed glazing units. Dual colour finishes carry a 15% surcharge.
Design Your Casement Window
Choose your configuration, dimensions, colours, and glazing in our 3D tool. Instant pricing — no waiting for supplier quotes.
Open the ConfiguratorWhy Timber Casement Windows?
Thermal Performance
Timber is a natural insulator. Our casement frames achieve significantly better thermal performance than aluminium or uPVC alternatives. Combined with our double, triple, or passive glazing options (U-values down to 0.8 W/m²K), a timber casement window is the best performing window you can install.
Lifespan
A properly maintained timber casement window lasts 60 to 100 years. Our Accoya timber is guaranteed for 50 years against rot and fungal decay. Compare that with uPVC, which typically degrades within 20 to 25 years and cannot be repaired — only replaced.
Sustainability
Timber is the only renewable window frame material. Our Accoya is FSC certified and sourced from sustainably managed forests. At end of life, timber is biodegradable. uPVC is not.
Security & Compliance
- PAS24 enhanced security — standard on every casement window, no upgrade charge
- Part L compliant — all glazing options meet current thermal requirements
- FENSA registered — Building Regulations self-certification and certificate
- Espagnolette locking — multi-point locking on all opening casements
- Fire escape compliant — egress hinges available on specified windows
Areas We Cover
We manufacture and install casement windows across all London boroughs and Hertfordshire. Free site surveys across our coverage area. Our most active areas include Wandsworth, Chiswick, Richmond, Dulwich, Hampstead, Muswell Hill, Crouch End, and St Albans.
Get Your Casement Window Quote
Design it yourself in 3D or book a free site survey. We will take care of the rest.
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