Timber Sash Windows
From listed Georgian townhouses to contemporary residences, our sash windows are chosen by architects, conservation specialists and homeowners who want authentic detailing without compromising on performance. Every window is made to measure in engineered FSC®-certified timber, with slim profiles, elegant glazing bars and factory-applied finishes that last.
Made to measure
every window
manufactured to your exact
dimensions and detailing.
Two authentic systems
traditional Weights & Cords
or discreet Spring Balance.
Heritage detailing
deep mouldings,
slim meeting rails,
true or applied glazing bars.
Tested performance
U-values from 1.0 W/(m²·K),
PAS 24:2016 certified
security option, acoustic glazing.
Weight & Cords Collection
See specifications →
Spring Balance Collection
ll the elegance of a sliding sash with a concealed spring mechanism — slimmer frames, easy operation and excellent thermal performance. Ideal for renovations and new builds inspired by classic design.
See specifications →
View technical specifications
Glazing unit:
24-38 mm
Pane:
Ug 1.0 W/(m²·K)
Spacer:
WARM
Material:
PINE JOINTED / MERANTI / OAK / SAPELE / ACCOYA
Fitting:
CALDWELL / MIGHTON
Colour:
VARNISH COLORS / RAL / F&B
Gasket:
QLON
Silicone:
WHITE / BLACK / CLEAR / GREY / BROWN
Frame width:
134 mm
Glazing unit:
14-30 mm
Pane:
Ug 1.0 W/(m²·K)
Spacer:
WARM
Material:
PINE JOINTED / MERANTI / OAK / SAPELE / ACCOYA
Fitting:
CALDWELL / MIGHTON
Colour:
VARNISH COLORS / RAL / F&B
Gasket:
QLON
Silicone:
WHITE / BLACK / CLEAR / GREY / BROWN
Frame width:
146 mm
Heat Transfer Coefficient:
1.3 W/(m²·K)
Glazing unit:
24-28 mm
Pane:
Ug 1.0 W/(m²·K)
Spacer:
WARM
Material:
PINE JOINTED / MERANTI / OAK / SAPELE / ACCOYA
Fitting:
CALDWELL / MIGHTON
Colour:
VARNISH COLORS / RAL / F&B
Gasket:
QLON
Silicone:
WHITE / BLACK / CLEAR / GREY / BROWN
Frame width:
146 mm
Heat Transfer Coefficient:
1.4 W/(m²·K)
Glazing unit:
14 mm
Pane:
Ug 1.7 W/(m²·K)
Spacer:
WARM
Material:
PINE JOINTED / MERANTI / OAK / SAPELE / ACCOYA
Fitting:
CALDWELL / MIGHTON
Colour:
VARNISH COLORS / RAL / F&B
Gasket:
QLON
Silicone:
WHITE / BLACK / CLEAR / GREY / BROWN
Frame width:
134 mm
Glazing unit:
14 mm
Pane:
Ug 1.7 W/(m²·K)
Spacer:
WARM
Material:
PINE JOINTED / MERANTI / OAK / SAPELE / ACCOYA
Fitting:
CALDWELL / MIGHTON
Colour:
VARNISH COLORS / RAL / F&B
Gasket:
QLON
Silicone:
WHITE / BLACK / CLEAR / GREY / BROWN
Frame width:
134 mm
CAD drawings available on request.
Sash windows in completed projects
Who we work with
Whatever the scale — from a single window to a multi-plot development — we tailor our joinery, logistics and support to the way you work.
Developers & investors
Serial orders for residential schemes, delivered on schedule and adapted to project specifications.
Architects & designers
Technical support at design stage, drawings and bespoke solutions for demanding briefs.
Builders & installation companies
Reliable lead times, transparent logistics and support from first survey to handover.
Private clients
Individually made windows and doors for homeowners who value authenticity and craftsmanship.
Heritage & conservation projects
Faithful recreation of historical joinery, in line with conservation requirements.
Case studies
Traditional Box Sash Windows
— Westminster, London
The primary challenge at Harrow Road was replacing the old, draughty windows that failed to block out the noise from the busy street and caused significant heat loss. The solution involved a comprehensive installation of modern, energy-efficient and soundproof sash windows, whilst maintaining the consistent aesthetic of the building’s façade. As a result, the residents now enjoy vastly improved acoustic and thermal comfort, and the entire property has benefited from a refreshed, more contemporary exterior.
Location: Harrow Road, City of Westminster, London
Year: 2020
Systems: Sash Standard Plus (box sash)
FAQ
Are your products suitable for listed buildings and conservation areas?
Many of our projects involve heritage properties. We recreate original detailing — profiles, glazing bars, finishes — and work with architects and heritage inspectors, so we understand the requirements of conservation officers and planning authorities.
Which timber species do you offer?
All products are made from engineered, multi-layer timber certified FSC® or PEFC, which ensures dimensional stability and resistance to warping. Available species: pine, oak, meranti, sapele, red grandis and Accoya.
Can I choose double or triple glazing?
Yes. We fit double and triple glazed units with low-E coatings and warm-edge spacers, with options including acoustic, toughened, laminated and ornamental glass, plus inter-pane or applied glazing bars.
What guarantee do you provide?
We provide a 5-year guarantee covering the joinery construction, factory-applied coatings, glazing units and hardware (coatings without a UV filter carry a 2-year guarantee). Full guarantee terms are available on request.
What is the difference between weights & cords and spring balance sash windows?
Weights & cords is the original construction: the sashes are counterbalanced by weights concealed in the box frame, giving the authentic operation required in many conservation projects. Spring balance replaces the weights with a hidden spring mechanism, allowing slimmer frames and easier operation — a popular choice for renovations and new builds.
Can I have double glazing in a sash window for a listed building?
In many cases, yes. We manufacture our own slim double-glazed units — starting from just 4/6/4 mm — with heritage-style glazing bars that closely replicate the appearance of original single glazing. For strict conservation requirements we also offer dedicated renovation solutions, and we can support discussions with conservation officers.
Are sash windows draughty?
Not any more. Our sash windows use high-performance brush and compression seals integrated into the frame, tested for wind and water tightness to EN standards — combining the classic look with modern comfort.
Can you replicate my existing original windows?
Yes. Recreating historical joinery is one of our specialisms. We reproduce profiles, glazing bar layouts, horns and mouldings based on surveys, drawings or photographs of the original windows.
Do you offer an enhanced-security sash window?
Yes — the Sash BPL SBD 150 system is designed for projects with enhanced security requirements and is certified to PAS 24:2016, the British security standard recognised by insurers.
Request a free,
no-obligation quote
We respond within 48 hours.
Manufacturing timber joinery since 2011
FSC® & PEFC certified timber
PAS 24:2016 certified systems
5-year product guarantee
Weekly deliveries to the UK